The Effect of Omega-3 Docosahexaenoic Acid Supplementation on Gestational Length: Randomized Trial of Supplementation Compared to Nutrition Education for Increasing n-3 Intake from Foods.

Objective: DHA supplementation was compared to nutrition education to increase DHA consumption from fish and DHA fortified foods.

Design: This two-part intervention included a randomized double-blind placebo controlled DHA supplementation arm and a nutrition education arm designed to increase intake of DHA from dietary sources by 300 mg per day.

Setting: Denver Health Hospitals and Clinics, Denver, Colorado, USA.

Population: 871 pregnant women aged 18-40 were recruited between 16 and 20 weeks of gestation of whom 564 completed the study and complete delivery data was available in 505 women and infants.

Methods: Subjects received either 300 or 600 mg DHA or olive oil placebo or nutrition education.

Main Outcome Variable: Gestational length.

Results: Gestational length was significantly increased by 4.0-4.5 days in women supplemented with 600 mg DHA per day or provided with nutrition education. Each 1% increase in RBC DHA at delivery was associated with a 1.6-day increase in gestational length. No significant effects on birth weight, birth length, or head circumference were demonstrated. The rate of early preterm birth (1.7%) in those supplemented with DHA (combined 300 and 600 mg/day) was significantly lower than in controls.

Conclusion: Nutrition education or supplementation with DHA can be effective in increasing gestational length.