Maternal Obesity and Gestational Diabetes Are Associated with Reduced Placental Efficiency
Ellen Flatley, Amy Schilling, Terry Morgan. Oregon Health & Science University, Portland
Background: Nearly one-third of reproductive-age women are obese and many of these pregnancies are complicated by gestational diabetes (GDM), which increases the risk of fetal growth abnormalities and stillbirth. The mechanisms underlying these increased risks are poorly understood. We hypothesize that obesity and gestational diabetes may significantly increase placenta growth, thereby decreasing available nutrients to the fetus, so-called reduced placental efficiency.
Design: Retrospective analysis of 518 singleton placentas with available maternal and fetal metrics including pre-pregnancy body mass index (BMI), gestational diabetes diagnosed by glucose tolerance test (GTT), gestational age at delivery, birth weight, placental weight, and neonatal gender (260 males; 258 females). Obesity was defined as BMI of 30kg/m2 or greater. Placental efficiency was defined as birth weight (grams)/placental weight (grams). Data were analyzed by ANOVA with Bonferroni/Dunn post hoc testing.
Results: Approximately 40% of the mothers in our study were obese before pregnancy (211/518). Forty cases developed GTT proven GDM (8%). Placental efficiency increased with gestational age (R=0.58, p<0.0001) as fetal weight increased faster than placental weight. Therefore, all analyses were performed after adjusting for gestational age. We observed significant gender-effects. Compared to mothers with normal BMI, female babies from obese women without GDM (n=81) had significantly less placental efficiency (p=0.01) due to markedly increased placental weights (p<0.001). In contrast, males from obese women without GDM (n=90) had both increased birthweight and placental weight compared to normals and no significant decrease in placental efficiency. Although we had limited numbers of GDM cases, males (p=0.03), but not females, showed significantly reduced relative placental efficiency. This was a consequence of relatively greater placental weight (p<0.001) in these males compared with their birth weight and controls.
Conclusions: Given the current obesity epidemic, a better understanding between maternal BMI, gestational diabetes, and placental efficiency is required. Our data reveal significant gender effects and the potential importance of reduced placental efficiency in complications such as stillbirth.
Category: Gynecologic & Obstetrics
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 215, Wednesday Afternoon