13.2 Malpresentations, Breech & Obstructed Labor

Malpresentations, Breech & Obstructed Labor

1. Fetal Malpresentations and Malpositions

A presentation other than vertex (occiput presenting) is classified as a malpresentation (e.g., breech, face, brow, transverse lie/shoulder). A position other than occipito-anterior in vertex presentation is a malposition (e.g., occipito-posterior, occipito-transverse).

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2. Breech Presentation

Types of Breech Presentation

• Frank (Extended) Breech (65–70%): Fetal thighs are flexed at the hips and legs are extended at the knees over the anterior chest. Most common type at term; highest rate of successful External Cephalic Version (ECV) and trial of vaginal breech delivery.
• Complete (Flexed) Breech (25–30%): Fetal thighs are flexed at the hips and knees are flexed, bringing feet near the buttocks.
• Incomplete / Footling Breech (5%): One or both feet or knees present below the buttocks. Highest risk of umbilical cord prolapse (~15–20%).

Diagnosis & External Cephalic Version (ECV)

• Leopold Maneuvers: First maneuver reveals hard, round, ballotable head in the fundus. Third maneuver reveals soft, broad, non-ballotable buttocks over the pelvic inlet.
• External Cephalic Version (ECV): Manual rotation of fetus from breech to cephalic presentation performed at 36–37 weeks in non-laboring women.
  • Success rate: ~50%.
  • Contraindications: Antepartum hemorrhage (placenta previa/abruptio), severe preeclampsia/IUGR, oligohydramnios, uterine anomalies, previous C-section scar, multiple gestation, non-reassuring fetal heart trace.

Vaginal Breech Delivery & Specific Maneuvers

Vaginal breech delivery should only be attempted when strict criteria are met (frank/complete breech, estimated fetal weight 2.5–3.5 kg, flexed fetal head, normal maternal pelvis, experienced obstetrician).

1. Hands-Off Rule: Do NOT touch or pull on the fetus until the breech has delivered spontaneously up to the umbilicus to prevent arm extension or deflexion of the head.
2. Burns-Marshall Technique: For delivery of the trunk and shoulders. The fetus is allowed to hang by its own weight until the nape of the neck appears under the symphysis pubis. The feet are then grasped by the ankles and swept in an arc over the mother's abdomen.
3. Lovset Maneuver: For delivery of extended arms. The fetus is held by the pelvic girdle with thumbs on the sacrum. The body is rotated 180 degrees keeping the back uppermost, bringing the posterior arm anteriorly under the subpubic arch where it is delivered, then rotated 180 degrees back to deliver the other arm.
4. Mauriceau-Smellie-Veit (MSV) Maneuver: For delivery of the aftercoming fetal head. The fetus lies prone on the operator's forearm. The index and middle finger of one hand are placed on the fetal maxilla (malar bones) to maintain flexion, while the index and ring finger of the upper hand apply traction over the fetal shoulders/occiput.
5. Piper Forceps: Specialized long forceps applied to the aftercoming head if MSV fails or to control head delivery gently.

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3. Face, Brow, and Occipitoposterior Malpositions

Face Presentation

Engaging diameter is submentobregmatic (9.5 cm) when fully extended.

• Mento-Anterior (MA): Can deliver spontaneously vaginally by flexion.
• Mento-Posterior (MP): Persistent mento-posterior CANNOT deliver vaginally because the chest and head attempt to enter the pelvis together (engaging diameter >15 cm). Requires emergency C-section.

Brow Presentation

Fetal head is partially extended. Engaging diameter is the mentovertical diameter (13.5 cm)—the largest diameter of the fetal skull. Spontaneous vaginal delivery is impossible at term; requires C-section unless spontaneously converting to face or vertex.

Occipitoposterior (OP) Position & Deep Transverse Arrest

• Occipitoposterior (ROP/LOP): Occiput lies posteriorly near the sacroiliac joint. Requires long internal rotation of 3/8ths of a circle (135 degrees) anteriorly.
• Deep Transverse Arrest (DTA): Fetal head descends to the level of the ischial spines (station 0) in occipitotransverse position and fails to rotate due to flat (platypelloid) or android pelvis or uterine inertia. Treated with manual rotation or Kielland forceps delivery or C-section.

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4. Obstructed Labor

Definition and Etiology

Obstructed labor occurs when there is no progress in labor (no descent of the presenting part) despite strong, frequent, and coordinated uterine contractions.

• Causes: Cephalopelvic Disproportion (CPD), contracted pelvis, fetal malpresentations (transverse lie, persistent mento-posterior face, brow), fetal structural abnormalities (hydrocephalus, fetal ascites, sacrococcygeal teratoma), pelvic tumors (fibroids, ovarian cysts blocking the pouch of Douglas).

Pathognomonic Clinical Signs of Obstructed Labor

1. Maternal Signs: Exhaustion, high-grade fever, severe dehydration, dry coated tongue, tachycardia, ketoacidosis, oliguria, vulvar and cervical edema (due to compression against pelvic bone).
2. Bandl's Pathological Retraction Ring: A visible and palpable abnormal abdominal groove between the hyper-contracted, thickened upper uterine segment and the thinned-out, ballooned lower uterine segment. It rises progressively toward the umbilicus—a harbinger of impending uterine rupture.
3. Fetal Signs: Severe fetal distress (tachycardia/bradycardia, thick meconium), caput succedaneum Grade +++ (diffuse soft tissue edema over scalp), severe skull molding (+++ overlapping immovable cranial bones), fetal death.

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5. Complications & Emergency Management

Complications of Obstructed Labor

• Maternal: Rupture of the uterus, hypovolemic/septic shock, vesicovaginal fistula (VVF) and rectovaginal fistula (RVF) secondary to pressure necrosis of bladder/rectal mucosa against pubic bone, pelvic floor injury, puerperal sepsis, maternal death.
• Fetal: Severe birth asphyxia, intracranial hemorrhage, brachial plexus injury, stillbirth/fetal demise.

Management Protocol

1. Immediate Resuscitation: Stop oxytocin immediately if running. Rapid IV fluid resuscitation (Normal Saline / Ringer's Lactate) to correct dehydration and shock.
2. Broad-Spectrum IV Antibiotics: Ampicillin + Gentamicin + Metronidazole to combat polymicrobial intrauterine infection.
3. Catheterization: Insert Foley catheter to decompress bladder and monitor urine output (check for hematuria indicating bladder trauma).
4. Definitive Delivery:
   • Live Fetus: Emergency Cesarean Section under spinal or general anesthesia.
   • Dead Fetus: Emergency C-section is preferred if uterine rupture is threatened or Bandl's ring is present. Destructive operations (craniotomy, decapitation, evisceration) are performed ONLY if the cervix is fully dilated, pelvis is adequate, fetus is dead, and the operator is skilled in an environment where C-section is unavailable.