Most women consume only 20% of the Recommended Daily Amount for DHA, which means most women have low levels and need supplementation. 4 studies in the US found that dosages of 300-600 mg/day of DHA were helpful in improving rates of early preterm birth, low birth weight, and gestational duration. Supplementation with DHA may also reduce the risk of gestational diabetes, preeclampsia, and some food allergies in infants.
Women with low seafood consumption (less than 1 serving/week of fatty fish) are most likely to benefit. Women who develop prenatal or postnatal depression may benefit from adding 1000 mg or more of EPA.