Diagnosis and screening of carbohydrate metabolism disorders
Timely detection of endocrine pathology in pregnant women begins with the assessment of risk factors: family history of diabetes, history of gestational diabetes mellitus (GDM), abnormal lipid/fat metabolism, as well as giving birth to a child weighing over 4 kg.
Primary diagnosis and screening are carried out in two stages:
- Before 24 weeks of gestation: fasting venous plasma is tested at the first visit. The diagnosis of GDM is established at a value of ≥ 5.1 mmol/L, but less than 7.0 mmol/L.
- At 24–28 weeks of gestation: all women without previously detected disorders undergo an oral glucose tolerance test (OGTT) with 75 g of glucose. Diagnostic criteria for GDM are a glycemia level at 1 hour ≥ 10.0 mmol/L or at 2 hours ≥ 8.5 mmol/L.
Management tactics, delivery, and RDS prevention
Pregnant women with diabetes mellitus require systematic planned inpatient treatment. The first hospitalization is indicated in the 1st trimester (или сразу при выявления ГСД) for insulin dose adjustment and dietary therapy training. The second hospitalization is carried out at 18–20 weeks to rule out fetal anomalies, and prenatal hospitalization is at 35–36 weeks for type 1 and type 2 diabetes and at 36–37 weeks for GDM.
The optimal delivery time is 37–38 weeks. Due to the high risk of antepartum fetal death, CTG monitoring in the hospital is performed twice a day.
A characteristic feature of the fetus in maternal diabetes is delayed maturation. To prevent respiratory distress syndrome (RDS) in case of fetal lung immaturity, corticosteroids are prescribed before delivery.
Delivery is carried out in specialized obstetric centers. Programmed vaginal delivery is preferred under glycemic control every 4 hours. Short-acting insulin is administered during labor; long-acting drugs are contraindicated. A 5% dextrose solution is used intravenously to prevent hypoglycemia.
Iodine deficiency and thyroid physiology
In the 1st trimester of pregnancy, the demand for thyroid hormones increases by 30–50%, and the demand for iodine by 1.5–2 times. Maternal hormones are fundamentally important for CNS formation and embryogenesis.
Iodine deficiency is dangerous due to the development of endemic cretinism—a severe impairment of the child's physical and mental development. Prevention is carried out by prescribing potassium iodide at a dose of 250 mcg/day at the planning stage, during gestation, and during breastfeeding.
Thyroid stimulation against the background of micronutrient deficiency can cause euthyroid goiter (an increase in tissue volume by ≥20% without function alteration), which is associated with the risk of delayed fetal thyroid development.
Hypothyroidism: compensation criteria and management
Hypothyroidism occurs in 0.3–3% of pregnant women and, if left uncorrected, leads to miscarriages, anemia, premature placental abruption, hemorrhage, and fetal growth restriction. Treatment consists of prescribing hormone replacement therapy with levothyroxine sodium preparations.
Target thyroid-stimulating hormone (TSH) levels:
- 1st trimester: 0.1–2.5 mIU/L;
- 2nd trimester: 0.2–2.0 mIU/L;
- 3rd trimester: 0.3–3.0 mIU/L.
Monitoring of TSH and free thyroxine (free T4) levels is carried out monthly.
Briefly: answers to topical questions
What fetal and neonatal complications are characteristic of maternal diabetes mellitus?
Maternal diabetes mellitus is characterized by the development of diabetic fetopathy, malformations, and specific complications of the neonatal period.
Main complications:
- Diabetic fetopathy — large body mass, head-to-trunk disproportion, edema, moon facies, hypertrichosis.
- Malformations — lesions of the central nervous system, heart, bones, gastrointestinal tract, and urinary tract.
- Neonatal complications — delayed adaptation, hypoglycemia, respiratory distress syndrome, cardiomyopathy, polycythemia, hyperbilirubinemia.
- Electrolyte disturbances — hypokalemia, hypomagnesemia, hypocalcemia.
What anatomical and physiological changes of the respiratory system normally occur during pregnancy?
Normally, during pregnancy, oxygen demand increases by 20%. Physiological edema of the mucosa of the nasopharynx, trachea, and large bronchi, as well as physiological hyperventilation, are possible.
Which drug groups are used for the baseline therapy of bronchial asthma in pregnant women?
Inhaled anti-inflammatory drugs are used for the baseline therapy of bronchial asthma in pregnant women.
Main groups of agents:
- Glucocorticosteroids — inhaled forms are preferred, systemic drugs should be avoided.
- Mast cell stabilizers — cromones.
- Leukotriene receptor antagonists — antileukotriene drugs.
- Long-acting beta-2 agonists — used in combination with inhaled glucocorticosteroids (e.g., formoterol).
Remember the key glycemic thresholds in the OGTT: 5.1 (fasting) — 10.0 (at 1 h) — 8.5 (at 2 h). For TSH in the 1st trimester, the upper target limit is 2.5 mIU/L.
Class and exam questions
Why are corticosteroids prescribed to pregnant women with diabetes mellitus?
In the fetus against the background of maternal diabetes, delayed organ maturation is often noted. Corticosteroids are prescribed for fetal immaturity to prevent respiratory distress syndrome.
Is it possible to take oral hypoglycemic pills during lactation?
No, oral hypoglycemic agents are contraindicated during lactation due to the risk of hypoglycemia in the infant. Patients with type 1 and type 2 diabetes are indicated exclusively for insulin therapy.
What iodine deficiency prevention is recommended during pregnancy?
Daily intake of potassium iodide preparations at a dose of 250 mcg/day is indicated starting from the planning stage and throughout the entire period of gestation and lactation.
What is the risk of developing diabetes in a woman with a history of GDM?
In 25–50% of women who had gestational diabetes mellitus, overt diabetes mellitus (predominantly type 2) develops in the future, which requires follow-up by an endocrinologist.
What else to study on this topic
- Ultrasound signs of diabetic fetopathy and criteria for fetal macrosomia
- Features of insulin dose adjustment during labor and prevention of hypoglycemia with dextrose
- Indications for emergency cesarean section in endocrine pathologies
- Laboratory monitoring of diabetes compensation: HbA1c, glycemia, and ketonuria
- Management tactics for pregnancy in nodular and diffuse euthyroid goiter
Master the entire topic in the "Obstetrics and Gynecology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Respiratory diseases during pregnancy" and another 973 pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 21 video lessons on the subject
Other topics in the "Obstetrics" section
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.