Placental location and newborn weight

Previous studies suggest that placental location may affect fetal growth and the risks of preterm birth and preeclampsia. We studied the association between placental location and newborn weight.

We conducted a retrospective cohort study of 796 consecutive singleton births in women who delivered at ≥ 37 weeks' gestation between July and October 2009. We evaluated placental location at the time of the second trimester prenatal ultrasound at 16 to 24 weeks' gestation. Placental location was classified as lateral or central/fundal. We assessed the difference in newborn weight according to placental location and the incidence of small for gestational age birth weight < 10th percentile and pregnancy-induced hypertension. Using logistic regression analysis, odds ratios were adjusted for maternal age, world region of birth, gravidity, parity, maternal weight, history of hypertension or diabetes, current smoking or illicit drug use, and infant sex.

Among women with lateral versus central/fundal placentas, the respective mean (SD) birth weights were 3298 (550) g and 3352 (579) g (mean difference 54 g, 95% CI 53 to 161; P = 0.32). Relative to central/fundal location, laterally located placentas had an adjusted OR of 0.81 (95% CI 0.42 to 1.54) for SGA and 0.62 (95% CI 0.18 to 2.10) for preeclampsia/gestational hypertension.

Placental location was not associated with differences in newborn weight or other perinatal outcomes.