CONTEXT: Maternal obesity in pregnancy has profound impacts on maternal metabolism and promotes placental nutrient transport, which may contribute to fetal overgrowth in these pregnancies. The fatty acid docosahexaenoic acid (DHA) has bioactive properties that may improve outcomes in obese pregnant women by modulating placental function. OBJECTIVE: To determine the effects of DHA supplementation in obese pregnant women on maternal metabolism and placental function. DESIGN: Pregnant women were supplemented with DHA or placebo. Maternal fasting blood was collected at 26 and 36 weeks' gestation, and placentas were collected at term. SETTING: Academic health care institution. SUBJECTS: Thirty-eight pregnant women with pregravid body mass index ≥30 kg/m2. INTERVENTION: DHA (800 mg, algal oil) or placebo (corn/soy oil) daily from 26 weeks to term. MAIN OUTCOMES: DHA content of maternal erythrocyte and placental membranes, maternal fasting blood glucose, cytokines, metabolic hormones, and circulating lipids were determined. Insulin, mTOR, and inflammatory signaling were assessed in placental homogenates, and nutrient transport capacity was determined in isolated syncytiotrophoblast plasma membranes. RESULTS: DHA supplementation increased erythrocyte (P < 0.0001) and placental membrane DHA levels (P < 0.0001) but did not influence maternal inflammatory status, insulin sensitivity, or lipids. DHA supplementation decreased placental inflammation, amino acid transporter expression, and activity (P < 0.01) and increased placental protein expression of fatty acid transporting protein 4 (P < 0.05). CONCLUSIONS: Maternal DHA supplementation in pregnancy decreases placental inflammation and differentially modulates placental nutrient transport capacity and may mitigate adverse effects of maternal obesity on placental function
