USMLE Step 2 CK obstetrics questions

The measles-mumps-rubella (MMR) vaccine is a live attenuated vaccine and is contraindicated during pregnancy due to a theoretical risk to the fetus. Women found to be nonimmune to rubella during pregnancy should be counseled to avoid exposure to rubella and should receive the MMR vaccine after delivery, before hospital discharge if possible. There is no role for immune globulin or repeat testing to confirm nonimmune status in this context. Postpartum vaccination protects the mother for future pregnancies and reduces the risk of congenital rubella syndrome in subsequent gestations.

• A. False-negative rubella IgG results are not a recognized common occurrence requiring repeat testing.
• B. MMR is a live vaccine and is contraindicated during pregnancy.
• C. Immune globulin is not indicated for rubella nonimmunity in the absence of known exposure.
• D. Repeat testing does not change management and delays appropriate counseling.

First-trimester combined screening, performed between 11 and 13 6/7 weeks of gestation, combines nuchal translucency measurement with maternal serum pregnancy-associated plasma protein-A (PAPP-A) and beta-hCG to estimate risk for trisomy 21 and trisomy 18. At 11 weeks, this is the appropriate screening option, as it is both timely and noninvasive. Cell-free fetal DNA is also noninvasive and highly sensitive but is a screening test, not typically the first discussed when nuchal translucency measurement is still obtainable, and professional guidelines recommend offering all screening options with discussion of test characteristics. The quad screen is performed later, at 15-22 weeks, and would not be the most timely choice for a patient at 11 weeks requesting the earliest possible screening.

• A. Cell-free DNA is a reasonable option but does not provide nuchal translucency information and is not the standard first-trimester combined approach at this gestational age.
• C. CVS is a diagnostic, invasive test, and the patient has declined invasive diagnostic testing.
• D. Maternal serum AFP alone is a component of second-trimester screening for neural tube defects, not a first-trimester aneuploidy screen.
• E. The quad screen is performed at 15-22 weeks of gestation and would require the patient to wait several weeks.

Rh(D)-negative women with a negative antibody screen should receive a standard dose of anti-D immune globulin (RhoGAM) at 28 weeks of gestation to prevent alloimmunization from occult fetomaternal hemorrhage, since the partner's Rh-positive status gives the fetus a chance of being Rh-positive. A second dose is given postpartum within 72 hours if the newborn is confirmed Rh-positive, not routinely at 40 weeks antenatally. Paternity testing is not required or practical to guide this decision, since fetal Rh status is not yet known and treatment is based on maternal risk. Waiting for antibody positivity defeats the purpose of prophylaxis, since immune globulin prevents sensitization and is not effective once antibodies have already formed.

• A. A second antenatal dose at 40 weeks is not standard protocol; the second dose is given postpartum if the infant is Rh-positive.
• B. Paternity testing is not a standard or practical step in guiding RhoGAM administration.
• C. Once alloimmunization has occurred, anti-D immune globulin is no longer effective, so prophylaxis must be given before antibodies form.
• E. Gestational age at delivery does not determine the need for routine antepartum prophylaxis at 28 weeks.

The two-step approach to gestational diabetes screening begins with a 1-hour plasma glucose measurement after a 50-g oral glucose load; a threshold value (commonly 130-140 mg/dL, depending on institution) is used to identify patients who require further testing. A value above the threshold, as in this patient, is not diagnostic by itself and requires confirmation with a 3-hour, 100-g oral glucose tolerance test, which uses fasting, 1-hour, 2-hour, and 3-hour glucose values to establish the diagnosis. Hemoglobin A1c is not used for gestational diabetes diagnosis because of the altered red blood cell turnover and plasma volume changes in pregnancy. The 1-hour test alone, even when elevated, is a screening tool and does not meet diagnostic criteria for gestational diabetes.

• A. Insulin therapy should not be initiated without first establishing a diagnosis with the confirmatory test.
• B. Hemoglobin A1c is not a validated diagnostic test for gestational diabetes.
• C. A single elevated 1-hour screening value is not diagnostic; confirmatory testing is required.
• D. Repeating the same screening test does not provide diagnostic confirmation and delays care unnecessarily.

The detailed fetal anatomic survey, often called the anomaly scan, is typically performed between 18 and 22 weeks of gestation. At this gestational age, fetal structures including the brain, face, spine, heart, abdominal organs, kidneys, limbs, and placenta are sufficiently developed to allow systematic evaluation for structural anomalies, and amniotic fluid volume is adequate for visualization. Performing the scan earlier may limit visualization of certain structures such as the fetal heart and kidneys, while performing it later can make complete assessment more difficult due to fetal positioning and reduced relative amniotic fluid space. This scan is also used to confirm gestational age, assess placental location, and screen for soft markers of aneuploidy.

• A. The glucose challenge test timing (24-28 weeks) is unrelated to the optimal window for anatomic survey.
• C. 24-28 weeks is beyond the optimal window and is more associated with growth assessment or glucose screening.
• D. At 16-18 weeks, several fetal structures, particularly the heart and kidneys, may not yet be fully visualized.
• E. 28-32 weeks is used for growth ultrasounds when indicated, not the standard anatomy survey.

An increased nuchal translucency measurement, even in the setting of a normal karyotype and normal microarray, is associated with an increased risk of major structural fetal anomalies, most notably congenital heart defects, as well as other genetic syndromes not detected by karyotype or microarray. The most appropriate next step is a detailed fetal echocardiogram, typically performed later in the second trimester, to evaluate for structural cardiac anomalies. Reassurance alone is inappropriate because the risk of cardiac defects remains elevated independent of chromosomal status. Repeating invasive testing is unnecessary once a normal karyotype and microarray have already been obtained.

• A. Maternal serum AFP is used for neural tube defect screening, not for evaluating the cardiac risk associated with increased nuchal translucency.
• B. Amniocentesis would duplicate genetic information already obtained by CVS and does not address the structural anomaly risk.
• C. Repeating CVS is unnecessary once a normal karyotype and microarray result have already been confirmed.
• E. Reassurance is inappropriate because increased nuchal translucency carries an independent risk of structural cardiac anomalies regardless of karyotype.

Average-risk women should take 0.4-0.8 mg of folic acid daily beginning at least 1 month before conception and continuing through the first 12 weeks of pregnancy to reduce the risk of neural tube defects. This dose is based on the demonstrated reduction in NTD incidence from periconceptional supplementation in large trials. The higher 4 mg dose is reserved for women at high risk, such as those with a prior pregnancy affected by a neural tube defect. Starting supplementation only after a positive pregnancy test misses the critical window, since neural tube closure occurs by about day 28 of embryonic development.

• A. This dose is excessive for an average-risk woman and the timing is too late to prevent neural tube defects.
• B. Starting at 12 weeks is far too late to prevent neural tube defects, which close by about 4 weeks gestation.
• D. This high dose is reserved for women with a prior neural tube defect-affected pregnancy, not average-risk women.
• E. Starting after a positive pregnancy test is too late, as neural tube closure occurs very early, and this dose is below the standard average-risk recommendation.

Low-dose aspirin (81 mg daily) is recommended for preeclampsia prophylaxis in women with at least one high-risk factor, including a history of preeclampsia, particularly if it led to preterm delivery. Therapy should be initiated between 12 and 28 weeks of gestation, ideally before 16 weeks, and continued daily until delivery. This regimen reduces thromboxane-mediated vasoconstriction and platelet aggregation, improving placental perfusion. Waiting until hypertension develops defeats the purpose of prophylaxis, which aims to prevent disease onset.

• A. Aspirin is a preventive measure started in high-risk women before disease onset, not a treatment initiated after hypertension develops.
• B. High-dose aspirin is not used for preeclampsia prophylaxis and increases bleeding and other risks without added benefit.
• D. Aspirin prophylaxis must be continued until delivery, not discontinued at 20 weeks, to maintain protective effect throughout pregnancy.
• E. Starting at 28 weeks is at the latest acceptable boundary and delays the protective effect; earlier initiation between 12-16 weeks is preferred for this high-risk patient.

Gestational hypertension is defined as new-onset blood pressure of 140/90 mm Hg or higher after 20 weeks gestation, on two occasions at least 4 hours apart, in a woman with previously normal blood pressure and without proteinuria or other features of preeclampsia. This patient's hypertension arose after 20 weeks with no prior history, and she lacks proteinuria or any severe features such as end-organ involvement or neurologic symptoms. If proteinuria or severe features later develop, the diagnosis would progress to preeclampsia. Chronic hypertension requires elevated blood pressure documented before 20 weeks gestation or before pregnancy, which is not the case here.

• A. There is no evidence of preexisting chronic hypertension, so superimposed preeclampsia cannot be diagnosed.
• B. Chronic hypertension requires elevated blood pressure documented before 20 weeks gestation or prepregnancy, which was not present here.
• D. Preeclampsia requires hypertension plus proteinuria or another sign of end-organ dysfunction, neither of which is present in this patient.
• E. Eclampsia requires new-onset seizures, which this patient does not have.

Preeclampsia with severe features is diagnosed when hypertension (systolic ≥160 mm Hg or diastolic ≥110 mm Hg) is accompanied by any severe feature, which includes a persistent severe headache, thrombocytopenia below 100,000/mm³, or elevated liver transaminases to twice the upper limit of normal. This patient meets severe-range blood pressure, has a severe headache, thrombocytopenia (95,000/mm³), and elevated AST, satisfying multiple criteria independent of the degree of proteinuria. Notably, the severity of proteinuria is no longer required to establish severe features, since the amount of protein does not correlate well with outcomes. This presentation does not fully meet HELLP criteria because hemolysis has not been demonstrated.

• B. Gestational hypertension excludes proteinuria or other organ involvement and does not describe this patient with multiple severe features.
• C. This label underestimates the severity; severe-range blood pressure, headache, thrombocytopenia, and elevated liver enzymes all indicate severe features.
• D. HELLP syndrome requires evidence of hemolysis (such as schistocytes, elevated bilirubin, or low haptoglobin) in addition to elevated liver enzymes and low platelets, which is not confirmed here.
• E. Eclampsia requires new-onset generalized seizures, which this patient has not had.

Magnesium sulfate is the drug of choice for seizure prophylaxis in women with preeclampsia with severe features, reducing the risk of progression to eclampsia. Its mechanism involves antagonism of NMDA receptors and calcium channel blockade at the neuromuscular junction and cerebral vasculature, which decreases neuronal excitability and causes cerebral vasodilation. It is typically given as an intravenous loading dose followed by a continuous infusion, with therapy continued through delivery and for 24 hours postpartum. Unlike antiepileptic drugs used for other seizure disorders, magnesium sulfate is specifically protective in the setting of preeclampsia-related eclampsia.

• A. Levetiracetam has no established role in preeclampsia seizure prophylaxis.
• B. Calcium gluconate is the antidote for magnesium toxicity, not a seizure prophylactic agent.
• C. Diazepam is used to terminate an active eclamptic seizure acutely but is not used for prophylaxis.
• D. Phenytoin has been studied for eclampsia prophylaxis but is inferior to magnesium sulfate and is not first-line.

This patient has signs of magnesium toxicity: absent deep tendon reflexes, respiratory depression (respiratory rate 10/min, oxygen saturation 90%), and altered mental status, indicating elevated serum magnesium levels beyond the therapeutic range. The infusion must be stopped immediately, and intravenous calcium gluconate should be given as the antidote, since calcium competes with magnesium at the neuromuscular junction and reverses its toxic effects. Clinical monitoring for magnesium toxicity includes serial assessment of deep tendon reflexes, respiratory rate, and urine output, since reduced reflexes typically precede respiratory depression. Prompt recognition and treatment prevent progression to respiratory arrest and cardiac toxicity.

• A. Naloxone treats opioid overdose and has no role in reversing magnesium toxicity.
• B. Increasing the infusion would worsen magnesium toxicity and risk respiratory and cardiac arrest.
• D. Oral magnesium would continue to raise magnesium levels and does not address the emergent toxicity.
• E. Diazepam would worsen respiratory depression and does not address the underlying cause of toxicity.

Intravenous labetalol is a first-line agent for acute treatment of severe hypertension in pregnancy (systolic ≥160 or diastolic ≥110 mm Hg), along with intravenous hydralazine and oral immediate-release nifedipine. It is a combined alpha- and beta-blocker that lowers blood pressure rapidly while generally preserving uteroplacental blood flow. The goal is to reduce severe-range blood pressure within 30-60 minutes to prevent maternal complications such as stroke, while avoiding excessively rapid drops that could compromise placental perfusion. Oral nifedipine, not the sublingual route, is used acutely; sublingual administration risks precipitous and unpredictable blood pressure drops.

• B. Furosemide is a diuretic and does not have a role in acute treatment of severe hypertension in preeclampsia.
• C. Sublingual nifedipine is not the recommended route; oral immediate-release nifedipine is used, as sublingual dosing can cause unpredictable, excessive hypotension.
• D. Methyldopa is used for chronic, non-severe hypertension management but has too slow an onset for acute severe hypertension.
• E. ACE inhibitors like lisinopril are contraindicated in pregnancy due to fetal renal toxicity and are not used for acute blood pressure control.

HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) is diagnosed here by schistocytes with elevated LDH and bilirubin indicating hemolysis, markedly elevated AST, and thrombocytopenia below 100,000/mm³. The definitive treatment for HELLP syndrome is prompt delivery, regardless of gestational age, since the maternal risks of ongoing hepatic injury, DIC, and hemorrhage outweigh the benefits of further fetal maturation. Magnesium sulfate should be given for seizure prophylaxis, and corticosteroids may be used for fetal lung maturity if time allows, but these are adjuncts rather than definitive therapy. Expectant management is not appropriate once HELLP syndrome is confirmed, as the condition can progress rapidly to life-threatening maternal complications.

• A. Plasma exchange is reserved for refractory cases resembling thrombotic microangiopathy, not first-line management of HELLP syndrome.
• B. Platelet transfusion alone does not address the underlying disease process, and continued expectant management risks rapid maternal deterioration.
• D. Magnesium sulfate is an important adjunct for seizure prophylaxis but observation without delivery is inappropriate once HELLP syndrome is diagnosed.
• E. Corticosteroids may aid fetal lung maturity but do not treat the underlying disease and are not a substitute for delivery.

This patient has preeclampsia without severe features (blood pressure under 160/110 mmHg, no severe-range symptoms, normal platelets, creatinine, and liver enzymes). Current ACOG guidance recommends delivery at 37 weeks' gestation for preeclampsia without severe features, balancing the risk of disease progression against neonatal risks of continued prematurity. Expectant management beyond 37 weeks is not recommended because of the risk of progression to severe disease, placental abruption, or stillbirth. If severe features were present at or beyond 34 weeks, delivery would be indicated immediately after stabilization rather than expectant management.

• A. Waiting until 40 weeks is inappropriate and increases maternal and fetal risk from ongoing preeclampsia.
• C. Waiting until 39 weeks exceeds the recommended delivery timing for preeclampsia without severe features and increases risk of progression.
• D. There is no indication for immediate delivery or corticosteroids since the patient does not have severe features and is already at 36 weeks.
• E. Immediate delivery is reserved for severe features or non-reassuring fetal status, which are absent here.

Insulin is the preferred pharmacologic agent for glycemic control in pregnancy because it does not cross the placenta in significant amounts and allows more precise, flexible dose titration to meet the changing insulin requirements of pregnancy. While metformin and glyburide cross the placenta and have been studied in gestational diabetes, insulin remains the standard for pregestational diabetes, especially when tighter control is needed as insulin resistance increases with advancing gestation. SGLT2 inhibitors and GLP-1 receptor agonists are not recommended in pregnancy due to insufficient safety data and are generally discontinued before conception.

• A. Metformin alone is often inadequate as pregnancy progresses because insulin resistance increases, and insulin offers more reliable control.
• B. GLP-1 receptor agonists are not recommended in pregnancy due to lack of safety data and are typically discontinued before conception.
• C. SGLT2 inhibitors are not recommended in pregnancy due to lack of safety data and potential fetal risk.
• D. Glyburide crosses the placenta and is not preferred over insulin for pregestational diabetes.

In a diabetic pregnancy with an estimated fetal weight of 4500 g or greater, ACOG recommends offering scheduled cesarean delivery to reduce the risk of shoulder dystocia and associated brachial plexus injury, because fetal macrosomia in diabetic mothers disproportionately increases shoulder and trunk size relative to head size. The macrosomia threshold for considering cesarean delivery is lower in diabetic pregnancies (4500 g) than in nondiabetic pregnancies (5000 g) due to this disproportionate growth pattern. Induction of labor does not reduce the risk of shoulder dystocia at this estimated weight and may increase the risk of a difficult vaginal delivery. Operative vaginal delivery with vacuum assistance would further increase the risk of shoulder dystocia in a macrosomic fetus.

• A. Expectant management increases fetal weight further and does not address the elevated risk of shoulder dystocia.
• B. External cephalic version is used for breech presentation, not for macrosomia, and is not indicated here.
• C. Operative vaginal delivery increases the risk of shoulder dystocia and brachial plexus injury in a macrosomic fetus.
• E. Induction of labor does not eliminate the risk of shoulder dystocia at this estimated fetal weight and is not the preferred management.

Chronic maternal hyperglycemia in diabetic pregnancy causes sustained fetal hyperglycemia, since glucose crosses the placenta freely, which in turn stimulates fetal pancreatic beta-cell hyperplasia and hyperinsulinemia. After delivery, the abrupt loss of the maternal glucose supply removes the stimulus for high insulin levels, but the neonate's hyperinsulinemic state persists transiently, driving rapid glucose uptake into tissues and causing hypoglycemia, typically within the first few hours of life. This mechanism explains why infants of diabetic mothers are monitored closely for hypoglycemia regardless of birth weight. The other listed mechanisms are not the primary physiologic cause of hypoglycemia in infants of diabetic mothers.

• B. Placental glucose transfer is typically increased, not impaired, in diabetic pregnancies, contributing to fetal hyperglycemia rather than hypoglycemia before birth.
• C. Hepatic glycogenolysis enzyme maturation is not the primary defect; the problem is excess insulin driving glucose uptake, not an inability to mobilize glycogen.
• D. Transient neonatal hypothyroidism is not characteristic of infants of diabetic mothers and does not explain their hypoglycemia.
• E. Adrenal insufficiency is not a feature of infants of diabetic mothers and is not the cause of their hypoglycemia.

Pregnancy increases thyroid hormone requirements because of elevated thyroxine-binding globulin from estrogen stimulation, increased plasma volume, and placental metabolism of thyroxine, so women with primary hypothyroidism typically need to increase their levothyroxine dose by about 25-30% as soon as pregnancy is confirmed. Thyroid-stimulating hormone should then be rechecked approximately every 4 weeks during the first half of pregnancy to titrate the dose further and keep it within the trimester-specific target range. Continuing the preconception dose unchanged risks maternal and fetal hypothyroidism, which is associated with adverse outcomes including miscarriage and impaired fetal neurodevelopment. Levothyroxine, not liothyronine, is the standard replacement therapy because it provides a stable, physiologic source of thyroid hormone for conversion to the active form.

• A. Liothyronine is not used for maintenance therapy in pregnancy; levothyroxine remains standard treatment.
• C. Discontinuing levothyroxine would cause maternal hypothyroidism, which is harmful to both mother and fetus and is never appropriate in a woman with primary hypothyroidism.
• D. Levothyroxine requirements increase, not decrease, in pregnancy due to higher thyroxine-binding globulin and placental hormone metabolism.
• E. Continuing the same preconception dose risks undertreatment because thyroid hormone requirements increase substantially in early pregnancy.

Asymptomatic bacteriuria in pregnancy must be treated because, if untreated, approximately 20-30% of affected women progress to pyelonephritis, which is associated with preterm labor, low birth weight, and maternal sepsis. Nitrofurantoin for 5-7 days is a first-line option for asymptomatic bacteriuria in pregnancy, along with amoxicillin or cephalexin, chosen based on susceptibility and gestational age (nitrofurantoin is generally avoided near term due to theoretical neonatal hemolysis risk). Unlike in nonpregnant women, screening and treatment of asymptomatic bacteriuria is standard of care in pregnancy because of the significant maternal and fetal risks if it progresses to symptomatic infection.

• A. Asymptomatic bacteriuria in pregnancy requires treatment, unlike in nonpregnant women, because of the high risk of progression to pyelonephritis.
• C. Delaying treatment risks progression to pyelonephritis before the repeat culture is even obtained.
• D. Treatment should be given now based on the positive culture, not withheld until symptoms of infection develop.
• E. Intravenous antibiotics are not necessary for asymptomatic bacteriuria; oral therapy is appropriate and sufficient.

Pyelonephritis in pregnancy is diagnosed clinically based on fever, flank pain, costovertebral angle tenderness, and pyuria with a urine culture obtained to guide therapy, and it is managed with inpatient admission for intravenous antibiotics such as ceftriaxone, a broad-spectrum cephalosporin with good activity against the typical uropathogen Escherichia coli. Patients are typically continued on IV antibiotics until afebrile and clinically improved for 24-48 hours, then transitioned to oral antibiotics to complete a 10-14 day course based on culture sensitivities. Outpatient management is not appropriate because pregnant women with pyelonephritis are at increased risk for sepsis, preterm labor, and respiratory complications, warranting close inpatient monitoring. Delivery is not indicated based on infection alone in the absence of obstetric indications or failure of medical therapy.

• A. Cesarean delivery is not indicated for pyelonephritis alone without obstetric indications or maternal instability refractory to treatment.
• B. Outpatient single-dose therapy is insufficient for pyelonephritis, which requires inpatient management until clinical improvement.
• C. Vancomycin plus piperacillin-tazobactam is excessive empiric coverage for uncomplicated pyelonephritis; a cephalosporin targeting typical gram-negative uropathogens is first-line.
• E. Outpatient oral therapy is inadequate for pyelonephritis in pregnancy, which requires inpatient intravenous antibiotics due to risk of sepsis and preterm labor.

Low-molecular-weight heparin, such as enoxaparin, is the anticoagulant of choice for VTE prophylaxis and treatment in pregnancy because it does not cross the placenta, has a predictable dose-response, and avoids the teratogenic and fetal bleeding risks of other agents. Dosing is typically weight-based and given subcutaneously, with monitoring adjusted as pregnancy progresses and maternal weight increases. LMWH is also preferred over unfractionated heparin outside of specific situations (e.g., need for rapid reversal near delivery) because it carries a lower risk of heparin-induced thrombocytopenia and osteoporosis.

• A. Aspirin is not therapeutic anticoagulation and does not treat an established DVT.
• B. Warfarin crosses the placenta and is teratogenic, causing fetal warfarin syndrome and fetal hemorrhage.
• C. Dabigatran, a direct thrombin inhibitor, crosses the placenta and is not recommended in pregnancy.
• E. Rivaroxaban, a direct factor Xa inhibitor, crosses the placenta and lacks safety data in pregnancy.

Painless third-trimester bleeding with a soft, nontender uterus and reassuring fetal status is classic for placenta previa, and transvaginal ultrasound is safe and accurate for localizing the placenta relative to the internal cervical os. Digital examination must be avoided until previa is excluded because palpation of a previa can disrupt placental vessels and precipitate severe hemorrhage. Transabdominal ultrasound can screen for previa but transvaginal ultrasound, performed carefully, gives superior visualization of the os-placenta relationship and is considered safe even with previa present.

• A. Emergency cesarean delivery is not indicated for a hemodynamically stable patient with reassuring fetal heart tracing and modest blood loss.
• C. Oxytocin is not indicated before the cause of bleeding and fetal status are established, and this patient is not in labor.
• D. Digital examination is contraindicated until previa has been excluded because it can provoke catastrophic hemorrhage.
• E. Amniotomy has no role here and could worsen bleeding if a previa is present.

Placental abruption classically presents with painful vaginal bleeding, a firm and tender uterus, frequent uterine contractions, and signs of fetal compromise such as late decelerations, and chronic hypertension is a major risk factor. This contrasts with placenta previa, which causes painless bleeding with a soft, nontender uterus. The diagnosis of abruption is primarily clinical, as ultrasound is insensitive for detecting retroplacental hemorrhage. Management depends on maternal and fetal status, ranging from expectant management to emergent cesarean delivery.

• A. Cervical insufficiency presents with painless cervical dilation, typically in the second trimester, without abruption-type bleeding or uterine tenderness.
• B. Uterine rupture typically occurs in a laboring patient with a prior uterine scar and presents with sudden loss of contractions and fetal station change, not a tender contracting uterus.
• D. Placenta previa causes painless bleeding with a soft, nontender uterus, not the painful, firm uterus seen here.
• E. Vasa previa presents with painless bleeding immediately after membrane rupture and rapid fetal heart rate abnormalities, not a tender contracting uterus.

When beta-hCG is below the discriminatory zone (typically around 1500-2000 mIU/mL) and ultrasound does not clearly show an intrauterine or ectopic pregnancy, the correct approach in a hemodynamically stable patient is serial beta-hCG measurement at 48-hour intervals. In a normal intrauterine pregnancy, beta-hCG should rise by at least 53-66% in 48 hours, whereas a slower rise or plateau suggests an abnormal pregnancy, including ectopic pregnancy. This avoids premature intervention before the pregnancy location is confirmed. If levels fail to rise appropriately or the patient becomes symptomatic, further evaluation or intervention follows.

• A. Dilation and curettage risks disrupting a normal intrauterine pregnancy and is not indicated without a confirmed diagnosis.
• B. Laparoscopy is invasive and unnecessary in a stable patient before the diagnosis is established with serial hCG and repeat ultrasound.
• D. Reassurance is inappropriate because the pregnancy location is not yet established and ectopic pregnancy has not been excluded.
• E. Empiric methotrexate is inappropriate without a confirmed diagnosis of ectopic pregnancy, as it would terminate a potentially normal intrauterine pregnancy.

This patient meets criteria for methotrexate therapy: hemodynamic stability, no evidence of rupture or peritoneal signs, beta-hCG below approximately 5000 mIU/mL, an unruptured mass less than 3.5-4 cm, no fetal cardiac activity, and normal liver and renal function. Methotrexate works as a folate antagonist that inhibits rapidly dividing trophoblastic tissue, avoiding surgery and preserving the fallopian tube. Contraindications include breastfeeding, immunodeficiency, hepatic or renal disease, and a visible fetal heartbeat, none of which are present here. Patients require close follow-up with serial beta-hCG levels to confirm resolution.

• B. Salpingostomy is a surgical option generally reserved when methotrexate is contraindicated or has failed, not first-line in an eligible stable patient.
• C. Antibiotics have no role in the treatment of ectopic pregnancy.
• D. Salpingectomy is reserved for ruptured ectopic pregnancy, hemodynamic instability, or failed medical therapy, none of which apply here.
• E. Expectant management is reserved for very low and declining beta-hCG levels with no mass or minimal findings, not an identified 2.5 cm mass with hCG 4800 mIU/mL.

A markedly elevated beta-hCG, uterine size greater than dates, early preeclampsia (hypertension before 20 weeks), hyperemesis, and the classic ultrasound "snowstorm" or cluster-of-grapes appearance with no fetal parts are diagnostic of a complete hydatidiform mole. Complete moles arise from fertilization of an empty ovum, resulting in purely paternal diploid genetic material and diffuse trophoblastic hyperplasia. Partial moles typically have an identifiable fetus with triploid karyotype and less extreme hCG elevation. Early-onset preeclampsia and markedly elevated hCG in the first trimester should always raise suspicion for molar pregnancy.

• B. Choriocarcinoma is a malignant sequela usually diagnosed after evacuation of a mole or other pregnancy, not an initial intrauterine finding at presentation.
• C. Partial mole usually shows an identifiable fetus with growth restriction and a triploid karyotype, not a complete absence of fetal parts.
• D. Multiple gestation would show multiple identifiable gestational sacs or fetuses, not a diffuse cystic mass without fetal parts.
• E. Missed abortion shows a nonviable fetus or empty gestational sac without the diffuse vesicular pattern or markedly elevated hCG seen here.

After evacuation of a hydatidiform mole, serial weekly serum beta-hCG monitoring is required until it is undetectable (typically three consecutive normal values), followed by monthly monitoring for several months, to detect persistent or malignant gestational trophoblastic disease such as invasive mole or choriocarcinoma. A plateau or rise in beta-hCG during surveillance signals the need for further evaluation and treatment. Patients are also advised to use reliable contraception during follow-up to avoid confounding a new pregnancy with recurrent disease. Prophylactic chemotherapy is not routinely indicated for low-risk complete moles.

• A. Hysterectomy is not indicated for routine surveillance of a mole in a patient desiring future fertility and without evidence of malignant disease.
• B. Prophylactic chemotherapy is not standard after evacuation unless there is evidence of persistent or malignant disease.
• C. Repeat curettage is not indicated for surveillance; it is only considered in specific cases of retained tissue or persistent disease after further evaluation.
• D. Chest radiograph is used for metastatic workup if malignant disease is confirmed, not as the primary surveillance strategy, and should not depend on symptom onset alone.

A missed abortion is diagnosed when ultrasound shows a fetus of appropriate size for gestational age with no cardiac activity, while the cervical os remains closed and products of conception have not been passed. This patient's bleeding and cramping reflect the body beginning to respond to fetal demise, but the pregnancy has not yet been expelled. Threatened abortion requires a closed os with a viable fetus showing cardiac activity, which is not the case here. Management options for missed abortion include expectant management, medical management with misoprostol, or surgical evacuation.

• A. Inevitable abortion is characterized by a dilated/open cervical os with intact membranes and no passage of tissue yet, not a closed os.
• B. Incomplete abortion shows a dilated os with partial passage of products of conception, not an intact closed-os gestation with no cardiac activity.
• C. Threatened abortion requires a closed os with a viable fetus and detectable cardiac activity, which is absent here.
• D. Septic abortion involves evidence of intrauterine infection such as fever, uterine tenderness, and purulent discharge, none of which are present here.

Vasa previa occurs when fetal vessels, unprotected by placental tissue or the umbilical cord, traverse the lower uterine segment near or over the internal cervical os. Risk factors include velamentous cord insertion, succenturiate or bilobed placenta, and pregnancies conceived by IVF, all of which are more common with low-lying placentas. Diagnosis is confirmed by transvaginal ultrasound with color Doppler showing these linear vascular structures overlying or near the os. If undiagnosed, rupture of these vessels during labor or membrane rupture can cause rapid fetal exsanguination and death, so antenatal detection allows for scheduled cesarean delivery before labor onset.

• B. Accreta involves abnormal placental invasion into the myometrium, not exposed fetal vessels over the cervix.
• C. Marginal cord insertion describes the cord attaching at the placental edge, not free vessels crossing the os.
• D. A succenturiate lobe is an accessory placental lobe; it is a risk factor for vasa previa but not the diagnosis itself.
• E. Abruption presents with vaginal bleeding and uterine pain, not isolated vessels over the os on Doppler.

In women with symptoms suggestive of preterm labor but an intermediate cervical length (20-30 mm) and a closed cervix, fetal fibronectin testing helps refine the risk of delivery within 7-14 days. Fetal fibronectin is a glycoprotein found at the choriodecidual interface; its presence in cervicovaginal secretions after 22 weeks indicates disruption of this interface and increased risk of preterm birth. A negative result has a high negative predictive value and can avoid unnecessary interventions such as hospitalization, corticosteroids, or transfer, while a positive result supports closer surveillance and treatment. It is not useful if membranes are ruptured, there is significant bleeding, or recent intercourse has occurred.

• B. A CBC is used to evaluate for infection, not to assess preterm delivery risk from contractions alone.
• C. CRP is nonspecific and not used to predict preterm delivery risk in this setting.
• D. Repeating cervical length in 24 hours delays risk stratification needed for immediate management decisions.
• E. Nitrazine testing evaluates for rupture of membranes, which is not suspected here given no reported fluid leakage.

Antenatal corticosteroids such as betamethasone cross the placenta and bind fetal glucocorticoid receptors, inducing enzymes that accelerate type II pneumocyte maturation, surfactant protein and phospholipid synthesis, and thinning of the alveolar septae. This reduces the incidence and severity of respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis in preterm neonates. A single course is recommended for women between 24 0/7 and 34 6/7 weeks of gestation at risk of delivery within 7 days, with maximal benefit when the first dose is given 24 hours to 7 days before delivery.

• A. Betamethasone acts on fetal tissue receptors directly rather than stimulating the fetal adrenal gland to produce more cortisol.
• B. Corticosteroids do not act primarily through increased uteroplacental blood flow.
• C. Reducing chorioamnionitis risk is not the mechanism of benefit for fetal lung maturation.
• D. Ductus arteriosus closure is not a relevant or intended effect of antenatal corticosteroids.

When given to women at risk of delivery before 32 weeks of gestation, magnesium sulfate has been shown in randomized trials and meta-analyses to reduce the risk of cerebral palsy and significant gross motor dysfunction in surviving infants, a benefit attributed to its neuroprotective effects on the developing fetal brain, possibly through reduction of excitotoxic injury and inflammation. This indication is distinct from its use for prevention of maternal eclamptic seizures in preeclampsia or as a tocolytic. The protocol typically involves a loading dose followed by a maintenance infusion for up to 12-24 hours or until delivery.

• A. Magnesium sulfate for neuroprotection does not reduce respiratory distress syndrome; that benefit comes from antenatal corticosteroids.
• C. Magnesium sulfate used for fetal neuroprotection is not intended or shown to meaningfully prolong pregnancy.
• D. Reduction in necrotizing enterocolitis is not the established benefit of magnesium sulfate given for neuroprotection.
• E. Eclampsia prevention is a separate indication for magnesium sulfate and is not relevant in this normotensive patient without preeclampsia.

This patient has preterm premature rupture of membranes (PPROM) confirmed by pooling, nitrazine positivity, and history, with no signs of infection, labor, abruption, or nonreassuring fetal status. At this gestational age (before 34 weeks), expectant management is preferred to allow for continued fetal maturation, combined with latency antibiotics (commonly a combination such as intravenous ampicillin followed by oral amoxicillin, plus azithromycin) to reduce the risk of maternal and neonatal infection and prolong the latency period. Daily assessment for signs of infection, abruption, or labor is essential, along with fetal surveillance. Antenatal corticosteroids have already been administered appropriately given the gestational age and risk of preterm delivery.

• A. Prolonged tocolysis beyond 48 hours is not recommended in PPROM due to increased infectious risk without proven benefit.
• B. Cesarean delivery is not indicated based solely on PPROM without labor, infection, or fetal distress.
• D. Immediate induction is not indicated in the absence of infection, nonreassuring fetal status, or advanced gestational age; expectant management is preferred before 34 weeks.
• E. Cerclage is not indicated after membrane rupture has already occurred and does not address the clinical scenario.

This fetus meets criteria for fetal growth restriction, defined as estimated fetal weight below the 10th percentile, here with an asymmetric pattern and mildly abnormal umbilical artery Doppler but preserved end-diastolic flow and a reactive fetal heart rate. In this setting without absent or reversed end-diastolic flow, standard management includes antenatal surveillance with twice-weekly biophysical profile or nonstress testing combined with serial umbilical artery Doppler studies, along with growth ultrasounds every 3-4 weeks, to monitor for deterioration while continuing the pregnancy toward term or near-term delivery around 37-38 weeks if stable. Immediate delivery is reserved for more severe Doppler abnormalities such as absent/reversed end-diastolic flow or nonreassuring testing.

• B. Immediate delivery is not indicated with normal diastolic flow and a reassuring fetal heart rate tracing; continued surveillance is preferred.
• C. Low-dose aspirin is used for preeclampsia prevention earlier in pregnancy, not as treatment for established fetal growth restriction in the third trimester.
• D. Continuous inpatient monitoring until spontaneous labor is not standard management for stable fetal growth restriction with reassuring testing.
• E. Waiting 4 weeks without interim antenatal testing risks missing deterioration in a growth-restricted fetus with abnormal Doppler findings.

Shoulder dystocia management follows a stepwise sequence beginning with the McRoberts maneuver, which increases the pelvic outlet by flattening the sacrum. If this fails, the next step is suprapubic pressure, which attempts to adduct the anterior shoulder and dislodge it from behind the pubic symphysis. Fundal pressure is avoided because it worsens impaction and increases the risk of uterine rupture and brachial plexus injury. More invasive maneuvers (internal rotation, delivery of the posterior arm, Zavanelli) are reserved for cases that fail suprapubic pressure.

• A. Cesarean delivery is not feasible once the fetal head has delivered; further vaginal maneuvers are attempted first.
• C. Zavanelli maneuver (cephalic replacement) is a last resort after all other maneuvers fail.
• D. Strong downward traction increases the risk of brachial plexus injury and should be avoided.
• E. Fundal pressure can worsen impaction of the anterior shoulder and increase the risk of fetal injury.

Umbilical cord prolapse is an obstetric emergency caused by compression of the cord between the fetal presenting part and the maternal pelvis, leading to fetal hypoxia. Immediate management involves manually elevating the presenting part to relieve cord compression while preparations are made for emergent cesarean delivery, as the cord cannot be safely reduced back above the presenting part. The patient should be placed in a knee-chest or Trendelenburg position, not lithotomy, and oxytocin is contraindicated since it would worsen contractions and cord compression. Terbutanline may be used temporarily to reduce contractions while preparing for delivery, but it does not substitute for mechanical relief of compression and expedited delivery.

• A. Amniotomy is irrelevant since membranes are already ruptured and the priority is relieving cord compression.
• B. Attempts to manually reduce the cord are generally unsuccessful and delay definitive treatment.
• C. Lithotomy position worsens cord compression and oxytocin would increase contractions, worsening fetal hypoxia.
• D. Expectant monitoring delays necessary emergency intervention and risks fetal demise.

Active genital herpes lesions or prodromal symptoms at the onset of labor are an indication for cesarean delivery to reduce the risk of neonatal herpes transmission, which carries high morbidity and mortality. This patient has active vesicular lesions consistent with an HSV outbreak, making cesarean the most appropriate route of delivery regardless of the time since her last outbreak. Vaginal delivery, with or without a fetal scalp electrode (which could inoculate the fetus with virus through a skin break), should be avoided when active lesions are present.

• A. Induction for vaginal delivery is contraindicated with active genital lesions.
• B. Vaginal delivery risks neonatal exposure to active HSV lesions during passage through the birth canal.
• C. Awaiting full dilation for vaginal delivery is inappropriate when active HSV lesions are present at labor onset.
• D. Scalp electrode placement creates a skin break that increases risk of direct viral inoculation of the fetus.

Uterine rupture is a feared complication of TOLAC, occurring in approximately 0.5-0.9% of patients with a prior low transverse cesarean scar. Classic findings include sudden severe abdominal pain that may break through epidural analgesia, loss of the previously palpable contraction pattern, fetal heart rate abnormalities (often bradycardia or a prolonged deceleration), and maternal tachycardia with hypotension from hemorrhage. Immediate emergency laparotomy and cesarean delivery are required to prevent fetal and maternal morbidity. Other complications such as abruption or amniotic fluid embolism can present with fetal distress but do not typically cause loss of the contraction pattern as seen with scar dehiscence.

• A. Placental abruption typically presents with vaginal bleeding and a hypertonic, tender uterus with a persistent contraction pattern rather than loss of contractions.
• B. Amniotic fluid embolism classically presents with sudden hypoxia, hypotension, and coagulopathy, not loss of the contraction pattern.
• D. Chorioamnionitis presents with maternal fever and uterine tenderness, not sudden pain with loss of the contraction pattern and hypotension.
• E. Uterine atony occurs after delivery of the placenta, not during active labor.

This patient has postpartum hemorrhage due to uterine atony, the most common cause, suggested by a soft, poorly contracted ('boggy') uterus above the umbilicus and risk factors including multiparity, macrosomia, and oxytocin-augmented labor. The initial step in management is bimanual uterine massage combined with uterotonic therapy (oxytocin) to stimulate myometrial contraction and control bleeding. Since the placenta is complete and there is no laceration, exploration for retained products or laceration repair is not indicated. Balloon tamponade and blood products are reserved for cases that fail initial uterotonic therapy.

• A. Examination showed no cervical laceration, so repair is not indicated.
• B. Fresh frozen plasma is used for coagulopathy, not as first-line therapy for atony without evidence of clotting abnormality.
• D. Balloon tamponade is used after uterotonics and massage fail to control bleeding from atony.
• E. The placenta is described as complete, making retained products unlikely as the cause.

Placenta accreta spectrum encompasses abnormal placental invasion into or through the myometrium, strongly associated with prior cesarean deliveries and placenta previa overlying the uterine scar. Characteristic ultrasound findings include multiple irregular placental lacunae with turbulent blood flow ('Swiss cheese' appearance) and loss of the normal retroplacental hypoechoic myometrial interface, indicating abnormal trophoblastic invasion. The number of prior cesarean deliveries is the strongest risk factor, with risk increasing significantly after three or more surgeries. Early antenatal diagnosis allows for planned delivery at a center with appropriate surgical expertise and blood bank resources.

• A. Circumvallate placenta shows a rolled chorionic plate edge, not vascular lacunae or myometrial interface loss.
• B. Vasa previa shows fetal vessels running through the membranes over the cervix, not placental lacunae or loss of the myometrial interface.
• C. Placental abruption presents acutely with retroplacental hemorrhage and clinical bleeding/pain, not the described lacunar pattern on routine ultrasound.
• D. A succenturiate lobe is an accessory placental lobe connected by vessels, unrelated to the lacunar and myometrial findings described.

Postpartum endometritis is a polymicrobial infection involving aerobic and anaerobic organisms from the genital tract, and the standard regimen is intravenous clindamycin plus gentamicin, which covers anaerobes (including Bacteroides) and gram-negative aerobes. This combination has been shown in clinical trials to achieve higher cure rates than single-agent therapy. Ampicillin is sometimes added for enterococcal coverage in refractory cases. Oral regimens are inadequate for this moderately ill, febrile postpartum patient who requires parenteral therapy. Fever typically resolves within 48-72 hours of starting appropriate antibiotics.

• A. Nitrofurantoin treats uncomplicated cystitis, not endometritis, and the urinalysis here is normal.
• B. Vancomycin alone does not cover the gram-negative and anaerobic organisms typical of endometritis.
• C. Oral therapy is inadequate for a febrile, tachycardic patient with endometritis requiring parenteral antibiotics.
• D. A single oral dose of azithromycin is insufficient for this polymicrobial pelvic infection.

Postpartum depression is diagnosed when depressive symptoms (anhedonia, sleep and appetite changes, feelings of worthlessness) persist beyond 2 weeks postpartum and impair functioning, distinguishing it from the self-limited postpartum blues, which resolves by day 10-14. This patient's low mood, weight loss, insomnia, and guilt have lasted beyond that window and represent a major depressive episode with postpartum onset per DSM-5 criteria (onset within 4 weeks of delivery). The absence of hallucinations, delusions, or disorganized behavior argues against postpartum psychosis, which is a psychiatric emergency requiring immediate hospitalization. Screening tools such as the Edinburgh Postnatal Depression Scale aid detection, and treatment includes psychotherapy and SSRIs such as sertraline.

• A. Her symptom pattern centers on depressed mood, guilt, and somatic changes rather than predominant excessive worry.
• B. Her presentation meets criteria for a major depressive episode rather than a subthreshold stress reaction.
• C. Postpartum psychosis involves hallucinations, delusions, or grossly disorganized thinking, none of which are present here.
• D. Postpartum blues is self-limited and resolves within about 2 weeks; this patient's symptoms persisted beyond that and are more severe.

This patient has lactational mastitis, suggested by fever, chills, and a localized area of erythema, warmth, and tenderness, distinguishing it from simple engorgement, which causes bilateral breast fullness without fever or focal erythema. First-line therapy is an antistaphylococcal penicillin such as dicloxacillin, since Staphylococcus aureus is the most common causative organism, along with continued frequent breastfeeding or pumping to promote milk drainage and prevent abscess formation. Stopping breastfeeding is not recommended because it increases milk stasis and worsens symptoms, and mastitis does not harm the infant. If a fluctuant mass develops suggesting abscess, ultrasound and drainage would then be indicated.

• A. There is no fluctuant mass to suggest abscess, so aspiration is not yet indicated.
• B. Febrile mastitis with systemic symptoms warrants antibiotics, not warm compresses alone.
• C. Stopping breastfeeding on the affected side increases milk stasis, worsening mastitis and raising abscess risk.
• D. Complete weaning is unnecessary and would worsen stasis; breastfeeding should continue during treatment.

Progestin-only contraceptives (pills, implants, or injections) are preferred in the early postpartum period for breastfeeding women because, unlike estrogen-containing methods, they do not suppress milk production or reduce milk volume. Combined hormonal contraceptives containing estrogen are classified as US Medical Eligibility Criteria category 2-4 in the first 30-42 days postpartum because estrogen can decrease lactation and increase venous thromboembolism risk, which is already elevated postpartum. There is no need to delay effective contraception until 6 months, since ovulation can resume as early as 3 weeks postpartum in women who are not exclusively breastfeeding. Progestin-only methods can be safely started immediately postpartum.

• A. Delaying contraception unnecessarily exposes her to risk of unintended pregnancy since ovulation can resume within weeks.
• B. The vaginal ring is a combined estrogen-progestin method with the same lactation and thrombosis concerns.
• D. The patch delivers estrogen as well and shares the same drawbacks for a breastfeeding woman this early postpartum.
• E. Combined pills contain estrogen, which can reduce milk supply and carry higher thrombosis risk in the early postpartum period.

ACE inhibitors such as lisinopril are contraindicated in pregnancy because second- and third-trimester exposure causes fetopathy, including oligohydramnios, renal dysgenesis, and skull hypoplasia, and first-trimester exposure has been associated with cardiac and central nervous system malformations. The appropriate action is to stop the ACE inhibitor and switch to a pregnancy-compatible antihypertensive such as labetalol, nifedipine, or methyldopa to maintain blood pressure control. Angiotensin receptor blockers like losartan share the same mechanism and are equally contraindicated in pregnancy. Stopping treatment altogether is inappropriate for a patient with chronic hypertension who needs ongoing blood pressure management, even if currently well controlled. Thiazide diuretics are not first-line for chronic hypertension in pregnancy and would not address the need to discontinue the teratogenic agent.

• A. Losartan is an angiotensin receptor blocker with the same renal and fetal toxicity as ACE inhibitors and is equally contraindicated.
• B. Chronic hypertension requires ongoing antihypertensive therapy; stopping treatment entirely risks poor blood pressure control.
• C. Adding a thiazide does not address the need to remove the teratogenic ACE inhibitor and is not first-line therapy in pregnancy.
• D. ACE inhibitors are contraindicated in pregnancy due to fetotoxicity and should be discontinued regardless of current blood pressure control.

Inactivated influenza vaccine and Tdap are both recommended during pregnancy regardless of prior immunization history, ideally given during the season they are indicated and between 27 and 36 weeks of gestation for Tdap to maximize passive antibody transfer to the neonate against pertussis. Both vaccines are inactivated or subunit vaccines and are safe at any trimester. Live vaccines, including MMR, varicella, and live attenuated intranasal influenza vaccine, are contraindicated in pregnancy due to theoretical risk to the fetus and should be deferred until the postpartum period. Deferring the inactivated vaccines to after delivery would unnecessarily delay maternal and neonatal protection during flu season and the Tdap window.

• A. MMR is a live vaccine and is contraindicated during pregnancy; it should be given postpartum instead.
• C. Deferring both vaccines unnecessarily delays protection, since inactivated influenza vaccine and Tdap are both safe and recommended in pregnancy.
• D. The live attenuated intranasal influenza vaccine is contraindicated in pregnancy; only the inactivated injectable form should be used.
• E. Varicella vaccine is live-attenuated and contraindicated in pregnancy.

Cesarean delivery for genital herpes is indicated only when there are active genital lesions or prodromal symptoms (vulvar pain, tingling, or burning) at the onset of labor, because these suggest viral shedding and risk of neonatal transmission during vaginal delivery. This patient has no visible lesions and no prodromal symptoms, so vaginal delivery is appropriate despite her history of recurrent herpes. Suppressive acyclovir starting at 36 weeks of gestation reduces the likelihood of an outbreak at term, but intravenous acyclovir during labor is not indicated in the absence of active disease. Artificial rupture of membranes is not specifically indicated or contraindicated based on herpes status alone when no lesions are present, and routine PCR testing in an asymptomatic patient without lesions is not necessary to determine mode of delivery.

• A. Cesarean delivery is reserved for active lesions or prodromal symptoms at labor onset, neither of which is present here.
• B. Intravenous acyclovir during labor is not the standard intervention when no active lesions or prodrome are present.
• C. Mode of delivery, not rupture of membranes timing, is the key decision point, and there is no clear indication to intervene with amniotomy here.
• D. Routine PCR testing in an asymptomatic woman without lesions does not change management and delays delivery unnecessarily.

The Jarisch-Herxheimer reaction is caused by the release of lipopolysaccharide-like endotoxin from dying treponemes after antibiotic therapy, triggering a systemic cytokine response with fever, chills, myalgias, and headache within 24 hours of treatment. In pregnancy, this reaction can also cause transient uterine contractions and fetal heart rate abnormalities due to maternal fever and cytokine release, but it is usually self-limited and managed with antipyretics, hydration, and continued fetal surveillance. Penicillin remains the only recommended and effective therapy for syphilis in pregnancy, so treatment should not be discontinued or switched to a non-penicillin agent, which does not reliably treat fetal infection. The reaction does not indicate treatment failure or an allergic reaction, so dose escalation or a different antibiotic is not needed.

• A. Ceftriaxone is not first-line for syphilis and is not indicated for managing this self-limited reaction.
• B. Repeating the dose is unnecessary; the reaction is an expected systemic response, not evidence of inadequate treatment.
• C. Doxycycline does not adequately treat fetal infection and penicillin remains the only recommended agent in pregnancy.
• D. Reassuring findings with transient decelerations resolving with conservative measures do not warrant emergency delivery.