Maternal mid-pregnancy lipids and birthweight.

Objective: To describe associations between maternal lipids and birthweight and to determine whether pre-pregnancy body mass index (BMI) modifies these associations.

Design: Cohort study.

Setting: Multiple communities in Michigan, USA.

Population: Participants were a sub-cohort of women from the multi-community Pregnancy Outcomes and Community Health (POUCH) study (1998-2004).

Methods: Maternal total cholesterol, high-density lipoprotein (HDLc), and low-density lipoprotein (LDLc) cholesterol, and triglycerides were assessed at 16-27 weeks' gestation. Women were classified as having normal (< 25 kg/m(2) ) or overweight/obese (≥ 25 kg/m(2) ) pre-pregnancy BMI.

Main Outcome Measures: Sex- and gestational-age-specific body weight z-score (BWz).

Results: Regression models examined associations among lipids (low: 1st quartile, referent: middle quartiles, high: 4th quartile) and BWz for the total sample and stratified by pre-pregnancy BMI. In adjusted analyses (n = 1207), low HDLc was associated with lower BWz (β = -0.23, 95% CI -0.40 to -0.06), whereas high triglycerides were associated with higher BWz (β = 0.23, 95% CI 0.06-0.41). Once stratified by pre-pregnancy BMI, low total cholesterol was associated with lower BWz in normal BMI women (β = -0.25, 95% CI -0.47 to -0.03), whereas in overweight/obese BMI women, high HDLc was inversely (β = -0.29, 95% CI -0.54 to -0.04) and high triglycerides were directly associated with BWz (β = 0.32, 95% CI 0.07-0.54). Removing women with gestational diabetes/hypertensive disorders did not alter the results.

Conclusions: The associations between maternal lipids and BWz vary by lipid measure and pre-pregnancy BMI. Future work should examine whether lipids and pre-pregnancy BMI make unique contributions to the fetal programming of disease.