Fish oil supplementation from the 24^th week of pregnancy led to a higher body mass index (BMI) in the offspring from age 0-6 years but not an increased risk of obesity at age 6. This according to the results from a randomized clinical trial of 736 pregnant women and their offspring that examined the effect of supplementation with n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) in pregnancy on anthropometry and body composition in offspring. Participants were randomized to either n-3 LCPUFA (fish oil) or control (olive oil) daily from pregnancy week 24 until 1 week after birth. Among the findings:

• n-3 LCPUFA supplementation in pregnancy led to increased BMI in childhood, with sustained elevated BMI from age 1-6 years.
• There was no difference in fat percentage.
• However, a proportional increase in lean mass, bone mass, and fat mass was observed at age 6 years.