Factors determining obstetric tactics
The choice of delivery method depends on a comprehensive assessment of maternal and fetal status. Key factors include:
- Age and parity: In nulliparous women over 30, there is a high risk of secondary uterine inertia in the second stage, when powerful pushing efforts are required to expel the fetus. In multiparous women, the birth canal tissues are already stretched, presenting fewer obstacles.
- Pelvic dimensions: Of critical importance. Even minimal pelvic contraction is unacceptable, as the aftercoming head has no time for molding (adapting to the pelvic shape), leading to severe trauma.
- Cervical ripening: Assessed via ultrasound and the Bishop score. An unripe cervix in a term fetus, especially against the background of premature rupture of membranes (PROM), is a prognostic sign of uterine inertia.
- Fetal weight: A fetus weighing more than 3600 g is considered macrosomic in a breech presentation for nulliparous women.
- Fetal condition: The presence of chronic hypoxia or fetal growth restriction (FGR) requires extremely careful management, as labor stress exacerbates these conditions.
Indications for cesarean section
Surgical delivery (elective cesarean section) is indicated in the presence of additional complicating factors. In multiparous women, these include:
- Estimated fetal weight of 3800 g or more.
- Excessive head extension (grade III).
- Hypoxia, grade III FGR, or their combination.
- Impaired blood flow in the mother-placenta-fetus system (confirmed by dopplerometry).
- Hemolytic disease of the fetus (HDF), especially in severe form.
- Pregnancy resulting from IVF.
- Unprepared birth canal in post-term pregnancy.
- Presence of a uterine scar or pelvic contraction.
- Extragenital pathologies requiring the avoidance of pushing efforts.
- Adverse outcome of previous deliveries.
Additionally, cesarean section is performed for a breech presentation of the first twin, as well as upon the patient's persistent request.
Conditions for vaginal delivery
Conservative management of labor is possible only with strict adherence to a number of conditions:
- The pregnancy must be at term.
- Maternal pelvic dimensions within normal limits.
- Fetal dimensions are average.
- The fetal head is flexed or only slightly extended.
- The cervix is fully mature.
- For nulliparous women, exclusively frank (pure breech) presentation is allowed.
- For multiparous women, both frank breech and complete breech presentations are possible.
Important: At the slightest complication from the mother or fetus during labor, tactics are immediately switched to emergency cesarean section. Extraction of the fetus by the pelvic pole is extremely rare in modern practice.
Management of the first stage of labor
The main tasks at this stage are to clarify the type of presentation, relieve labor pain, ensure fetal monitoring, and prevent early rupture of membranes or cord prolapse.
- Prevention of complications: Strict bed rest is prescribed to the parturient. It is optimal to lie on the side toward which the fetal back is turned — this not only enhances uterine activity but also promotes proper engagement of the presenting part.
- Tactics in case of membrane rupture: Immediately after amniotic fluid discharge, a mandatory vaginal examination is performed. Its purpose is to confirm the diagnosis and rule out umbilical cord loop prolapse.
Diagnostics and cardiomonitoring
With intact membranes, expectant management is applied. If ultrasound is unavailable, presentation is determined by Leopold maneuvers and vaginal examination (its accuracy increases significantly after membrane rupture).
- Frank breech presentation: Softish tissues, the sacrum, coccyx, ischial tuberosities, intergluteal cleft, inguinal fold, as well as the anus and genitalia are palpated (they should be palpated extremely carefully so as not to injure the fetus).
- Complete breech presentation: A foot is defined next to the buttocks.
- Footling presentation: Feet are palpated, and the buttocks are located higher.
Fetal position is established by the sacrum: if it faces left and anteriorly, it is the anterior variety of the first position; if right and posteriorly, the posterior variety of the second position.
CTG features: In breech presentation, the fetal lower limbs compress its abdomen, leading to irritation of the splanchnic nerve (n. splanchnicus). Because of this, cardiotocography often records tachycardia (especially at the end of the first and in the second stage), high baseline FHR, accelerations in response to contractions, and early decelerations during pushing.
Briefly: answers to topical questions
What are the steps of the biomechanism of labor in frank breech presentation?
The biomechanism of labor in breech presentation includes six main moments.
- First moment — internal rotation of the buttocks.
- Second moment — lateral flexion of the lumbar spine of the fetus.
- Third moment — internal rotation of the shoulders and external rotation of the trunk.
- Fourth moment — lateral flexion of the cervicothoracic spine.
- Fifth moment — internal rotation of the head.
- Sixth moment — flexion and delivery of the head.
What manual aids are used for fetal extraction during labor in frank breech presentation?
Several types of manual aids are used in labor with frank breech presentation.
- Tsovyanov's first manual maneuver — used to maintain normal fetal posture during the expulsion period.
- Mauriceau-Smellie-Veit maneuver — used for correct grasp and delivery of the aftercoming head.
- Classical manual maneuver — used to deliver the arms and head in case of delayed delivery or complications.
- Pinard maneuver — used in rare cases to convert a frank breech presentation into a footling breech for the purpose of fetal extraction.
What are the typical fetal complications that may occur during labor in a breech presentation?
The following typical fetal complications may occur during labor in a breech presentation.
- Umbilical cord compression — leads to acute hypoxia and potential fetal demise.
- Prolapse of the umbilical cord loops and small fetal parts — also carries the risk of cord compression.
- Arm entrapment (nuchal arm) — an alteration in the normal arm position that hinders spontaneous delivery.
- Head retraction (extension) — occurs in the persistent occipitoposterior position of a breech presentation.
- Extension of the fetal head — a classic complication that impedes passage through the birth canal.
- Head entrapment — can lead to injuries of the neck muscles, vertebral arteries, cervical spine, and spinal cord.
What are the grades of fetal head extension in breech presentation according to ultrasound data?
According to ultrasound data, there are three degrees of fetal head extension, which are assessed by the angle between the spine and the occiput.
- Grade I — mild extension (angle from 100° to 110°), also known as the "military posture".
- Grade II — moderate extension (angle from 90° to 100°).
- Grade III — severe extension (angle less than 90°), referred to as "stargazing" fetus.
At an angle greater than 110°, the head is considered flexed.
Class and exam questions
Why is even a minor maternal pelvic contraction dangerous in breech presentation?
When delivered in a breech presentation, the aftercoming head passes through the planes of the pelvis very rapidly. It simply does not have time to undergo molding (change shape and adapt to the pelvic dimensions), which creates a huge risk of severe trauma.
How to distinguish a frank breech from a complete breech presentation during vaginal examination?
In a frank (pure breech) presentation, the physician palpates only the fetal buttocks (sacrum, ischial tuberosities, intergluteal cleft). In a footling or complete breech presentation, a foot can additionally be palpated next to the buttocks.
What causes fetal tachycardia on CTG during labor in a breech presentation?
Tachycardia occurs due to a physiological mechanism: the fetal lower limbs press against its abdomen and compress it, which causes irritation of the splanchnic nerve (n. splanchnicus) and a reflex increase in heart rate.
What else to study on this topic
- Assessment of cervical maturity using the Bishop score and ultrasound data
- Differential diagnosis during vaginal examination: breech vs. face presentation
- Differential diagnosis of prolapsed fetal arm and leg
- Technique for total breech extraction
- Initial cardiotocographic signs of acute fetal hypoxia
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