Breech Birth

Basics

Description

At time of delivery, the sacrum or lower limbs are the presenting fetal part.

  • Frank breech: Fetal hips flexed and knees extended with feet near the face. Sacrum presents first (40–60% of breech presentations at term).
  • Footling or incomplete breech: Foot or knee presents first (25–35%).
  • Complete breech: Hips and knees flexed. Feet and sacrum present together (5–15%).

Epidemiology

Prevalence
Early gestational age is highly associated with breech presentation, and risk decreases as gestational age advances.

  • 22% of fetuses <28 weeks are breech.
  • 3–4% of singleton term fetuses
  • <10% of breech fetuses at term will spontaneously vert to cephalic.

Genetics
Associated with many fetal anomalies, including anencephaly, head or neck tumors, hydrocephalus, trisomies 21 and 18, Potter syndrome, myotonic dystrophy; associated with maternal müllerian uterine anomalies

Risk Factors

  • Early gestational age is number one risk factor.
  • History of breech birth
  • Low-birth-weight infant
  • Female gender
  • Fetal anomalies (9% of term breech and 17% of preterm breech)
  • Advanced maternal age
  • Oligohydramnios, polyhydramnios
  • Nulliparity, multiple gestation
  • Uterine anomalies, fibroids, or pelvic tumors
  • Pelvic contractures or irregularly shaped pelvis, such as android or platypelloid
  • Little evidence to support abnormal placentation (placenta previa, cornual-fundal) as a risk factor

General Prevention

  • Prenatal folate therapy to decrease risk of neural tube defects
  • Tight 1st-trimester glucose control in diabetics decreases anomalies.
  • Prenatal screening to diagnose chromosomal or fetal anomalies
  • Routine assessment of fetal presentation at 36 weeks to afford time for trial of external cephalic version (ECV)

Commonly Associated Conditions

  • Increased risk of cord prolapse (0.4% in cephalic presentation compared with 0.5% in frank breech, 4–6% in complete breech, and 15–18% in footling breech)
  • Congenital hip dysplasia has higher incidence in infants with breech presentation at term; more common in female infants than male

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