Association of elevated free fatty acids during late pregnancy with preterm delivery

To examine the association between moderately elevated maternal plasma free fatty acids (FFAs) during late pregnancy and preterm delivery.

In a prospective observational cohort with 523 healthy pregnant women, fasting plasma FFAs were measured during the third trimester. Socioeconomic, demographic, and anthropometric measures were collected at entry to prenatal care, and pregnancy outcomes were abstracted from medical record at delivery.

After control for confounders including prepregnant body mass index (multiple logistic regression analysis), women who had moderately elevated plasma FFAs (in the highest tertile), showed a greater than threefold increased risk of preterm delivery (adjusted odds ratio (AOR) 3.49, 95% (CI) 1.73-7.03, P<.001). The associations persisted in women who had spontaneous preterm delivery (AOR 2.35, 95% CI 1.05-5.28, P<.05) and after excluding women with gestational diabetes mellitus and preeclampsia (AOR 3.30, 95% CI 1.38-7.87, P<.01). Additional stratified analyses showed that the association of high maternal FFAs and increased risk of preterm delivery was independent of prepregnant obesity.

Elevated fasting plasma FFA levels at 30 weeks of gestation were associated with an increased risk of preterm delivery. This effect was independent of prepregnant obesity and several other known risk factors for preterm delivery, including cigarette smoking, ethnicity, and prior preterm delivery. These data may have important clinical significance because they provide a possible link between preterm delivery and high lipid levels, a known risk factor for cardiovascular disease.