Maternal body mass index and placental weight: a role for fetal insulin, maternal insulin and leptin

摘要

Purpose Placental weight (PW) has been found to mediate the main effect of maternal BMI on fetal size. Still, the BMI-PW association is poorly understood. Therefore, we aimed to explore potential explanatory variables, including gestational weight gain (GWG), early- and late-pregnancy circulating levels of maternal glucose, insulin, leptin, adiponectin, triglycerides, LDL-C, and HDL-C, and fetal insulin. Methods We included two studies of pregnant women from Oslo University Hospital, Norway: the prospective STORK (n = 263) and the cross-sectional 4-vessel method study (4-vessel; n = 165). We used multiple linear regression for data analyses. A non-linear BMI-PW association was observed, which leveled off from BMI25. Therefore, BMI = 25 were analyzed separately (n = 170/122 and 93/43 for STORK/4-vessel). Confounding variables included maternal age, parity, and gestational age. Results PW increased significantly per kg m(-2) only among BMI = 25 in STORK/4-vessel). Maternal early- but not late-pregnancy insulin and term fetal insulin were associated with PW. The estimated effect of early pregnancy insulin was similar between the BMI groups but statistically significant only among BMI = 25). Late pregnancy leptin was inversely associated with PW with a 1.3/1.7-fold greater effect among BMI >= 25 than BMI Conclusions The BMI-PW association was non-linear: an association was observed for BMI = 25. Leptin may be involved in the non-linear association through a placental-adipose tissue interplay. Maternal early pregnancy insulin and fetal insulin at term were associated with PW.