Objective: To determine whether elevated midpregnancy maternal serum lipid levels predict newborn weight at term and the risk of large for gestational age (LGA) infants in women with positive diabetic screen but normal glucose tolerance test.
Methods: Japanese gravidas who had positive diabetic screens and normal 75-g oral glucose tolerance tests (GTT) at 24--32 weeks were enrolled. Subjects with complications, including diabetes, hypertension, or fetal anomalies were excluded, as were women with multifetal gestations. Fasting serum triglyceride, free fatty acids, and total cholesterol levels were measured at the time of GTT. We tested the association between maternal variables and birth weight by univariable analysis. We used multivariable analysis to test whether the association between fasting lipids and birth weight was independent of prepregnant maternal body mass index (BMI), maternal weight gain during pregnancy, and plasma glucose levels at GTT. We also used multiple logistic regression analysis to determine whether maternal hyperlipidemia, defined as more than the 75th percentile of each lipid, is a risk factor for having an LGA infant.
Results: We enrolled 146 subjects. Among measured maternal lipids, only triglyceride levels correlated with birth weight in univariable analysis (r = 0.22, P =.009). Birth weight also was correlated with prepregnant maternal BMI (r = 0.18, P =.04) and fasting plasma glucose levels (r = 0.17, P =.04). The association between maternal fasting triglyceride level and birth weight remained significant after adjusting for prepregnant BMI, maternal weight gain, fasting plasma glucose levels, fetal gender, and gestational age at birth (P =.01). Logistic regression analysis showed that fasting maternal hypertriglyceridemia (over 259 mg/dL) was the significant predictor of LGA infants, independent of prepregnant BMI, maternal weight gain, and maternal plasma glucose levels (odds ratio 11.6; 95% confidence interval 1.1, 122; P =.04).
Conclusion: In women with positive diabetic screens but normal GTTs, fasting triglyceride levels at 24-32 weeks correlated positively with newborn weight at term, independent of maternal plasma glucose levels and obesity. Maternal fasting serum triglyceride levels in midpregnancy might be an independent predictor of fetal macrosomia in those women.