Fish oil supplementation

Question: Does supplementation with fish oil (omega-3 or n-3 fatty acids) during pregnancy affect placental function and fetal growth?

Answer: Oh yes. We studied placental metabolism in tissue collected from randomized controlled trial of women supplemented with fish oil or placebo from early second trimester to term. Fish oil supplementation decreased placental lipid content by 30% (see Figure) and impaired the placenta’s ability to store lipids (esterification).

Surprise: Babies born to the women randomized to fish oil supplements were larger, which could mean that placental lipid storage limits the amount of fat delivered to the baby.

So what: Many women supplement with fish oil during pregnancy, for its purported anti-inflammatory and plasma lipid lowering effects. However, we do not understand how these supplements alter placental function, thereby affecting the fetus.

Follow-up studies: We are now working with collaborators in Hawaii to measure placental lipid content and metabolism in mothers who naturally have a higher fish intake (Hawaiians) to compare to our Cleveland cohort (naturally lower fish intake). Then we will be able to answer whether dietary fish intake affects the placenta differently from fish oil supplements.


Calabuig-Navarro et al. 2016 Effect of ω-3 supplementation on placental lipid metabolism in overweight and obese women.