breech presentation

**Definition:** The fetal buttocks and/or lower extremities lie closest to the cervix (longitudinal lie, podalic pole presenting). Incidence is about 20-25% at 28 weeks, about 7% at 32 weeks, and about 3-4% at term, because most fetuses spontaneously convert to cephalic by term.

**Types:** - **Frank breech (about 65-70%):** Hips flexed, knees extended, feet near the head. Most common at term. Lowest risk of cord prolapse. - **Complete breech:** Hips and knees both flexed ("cannonball" position). - **Incomplete (footling) breech:** One or both feet or knees present below the buttocks. Highest risk of cord prolapse.

**Risk factors (anything that impairs fetal mobility or alters uterine or pelvic shape):** - Prematurity (the strongest association) - Multiparity (lax uterus) and multiple gestation - Polyhydramnios or oligohydramnios - Uterine anomalies (septate or bicornuate uterus), fibroids - Placenta previa or a cornual/fundal placenta - Fetal anomalies (anencephaly, hydrocephalus, neuromuscular disorders, trisomies 13/18/21) - Prior breech delivery - Pelvic or uterine abnormalities

**Diagnosis:** - Leopold maneuvers: a hard, round, ballotable head is palpated at the fundus. - Vaginal exam: a soft presenting part, sometimes with the anus or genitalia palpable. - **Ultrasound confirms the diagnosis** and assesses type, fetal anomalies, placental location, and amniotic fluid.

**Complications:** - **Umbilical cord prolapse** (highest with footling breech) - **Entrapment of the aftercoming head** (head larger than the body, so the cervix may close around the neck) - Birth trauma: brachial plexus injury (Erb palsy), intracranial hemorrhage, spinal cord injury, and fractures - Developmental dysplasia of the hip (DDH), which is increased in breech infants, especially frank breech and females. Screen with ultrasound at 6 weeks or later, even after cesarean delivery. - Perinatal asphyxia

**Management:** 1. **External cephalic version (ECV)** at ≥36-37 weeks. Success is about 50-60%. - Contraindications: placenta previa, abruption, non-reassuring fetal status, oligohydramnios, ruptured membranes, multiple gestation (relative), major uterine anomaly, and any other contraindication to vaginal delivery. - Rh-negative mothers should receive Rho(D) immune globulin because of the risk of fetomaternal hemorrhage. - Tocolytics (e.g., terbutaline) can improve success. - Risks: placental abruption, cord entanglement, fetal bradycardia, and emergency cesarean. Perform ECV where emergency cesarean is available, with fetal monitoring before and after. 2. **Planned cesarean delivery at 39 weeks** if ECV fails, is declined, or is contraindicated. This is the standard of care after the Term Breech Trial, which showed lower perinatal morbidity and mortality with planned cesarean. 3. **Vaginal breech delivery** is only appropriate for selected cases with an experienced provider and strict criteria: frank or complete breech, adequate pelvis, estimated fetal weight about 2,500-4,000 g, a flexed head, and no anomalies.

**Vaginal breech delivery maneuvers (high-yield):** - Allow spontaneous delivery to the umbilicus, then deliver the arms (Løvset maneuver for the arms). - Use the **Mauriceau-Smellie-Veit maneuver** or **Piper forceps** for the aftercoming head. - **Total breech extraction** is not recommended for a singleton, except for the second twin.

**Management pearls:** - If the fetus is breech in labor with advanced dilation and progress, in a mother without time for cesarean, deliver vaginally with hands off until the umbilicus is reached. - Cord prolapse is an obstetric emergency: elevate the presenting part off the cord manually, place the mother in knee-chest or Trendelenburg position, and proceed to emergent cesarean. - Breech at <36 weeks is generally observed, because spontaneous version is likely.

**Associations for boards:** Breech is associated with DDH, congenital anomalies, and prematurity. The classic exam question is a term primigravida with a breech fetus on ultrasound whose best next step is ECV at 36-37 weeks. If ECV is contraindicated, the answer is planned cesarean at 39 weeks.