Placental findings associated with maternal obesity at early pregnancy

Obesity during pregnancy is associated with a wide spectrum of maternal, fetal and neonatal complications. This study compared placental pathology in women with obesity and normal weight gravidas.

This is a retrospective case-control study. The sample was randomly selected from a total of 1000 deliveries of largely Caucasian population in a single institution, recruited for the study of sleep disordered breathing, where the placenta is submitted for pathological examination for clinical indications based on national guidelines. Cases (Body mass index - BMI ≥ 30 kg/m(2); n = 47) and controls (BMI < 25 kg/m(2), n = 45) were selected based on BMI obtained from the first prenatal visit. Placental pathology, clinical parameters and limited outcomes were extracted from medical records. Placental weight range was defined as small for gestational age (SGA) if < 10th percentile, large for gestational age (LGA) if > 90th percentile.

Mean BMI was 36.2 ± 5.5 in the group with obesity and 21.7 ± 1.9 in the control group (p < 0.01). There was a significantly higher prevalence of diabetes in cases compared to controls (14/47 vs. 3/45, p = 0.006) while preterm birth was significantly higher in the control group (9/47 vs. 19/46, p = 0.02). There were more LGA placentas in cases versus controls (12/47 vs. 2/46, p = 0.007; even after adjusting for diabetes). More histological features of inflammation, marginal insertion of the umbilical cord and intervillous thrombi in the parenchyma were also noted in the case group.

Results from the current study suggest that maternal obesity measured at early pregnancy may have effects on both placental implantation and growth, and further exacerbate the hypercoagulable state in placenta.