Fish oil supplementation during pregnancy and postpartum in mothers with overweight and obesity to improve body composition and metabolic health during infancy: a double-blind randomized controlled trial

Am J Clin Nutr. 2023 Feb 11:S0002-9165(23)04153-9. doi: 10.1016/j.ajcnut.2023.02.007. Online ahead of print.

ABSTRACT

BACKGROUND: Maternal obesity during pregnancy is associated with increased risk of obesity and metabolic disease in the offspring. Supplementation with fish oil (FO), which is insulin-sensitizing, during pregnancy in mothers with overweight or obesity may prevent the development of greater adiposity and metabolic dysfunction in their children.

OBJECTIVE: To determine the effects of FO supplementation throughout the second half of pregnancy and lactation in mothers with overweight or obesity on infant body composition and metabolism.

DESIGN: A double-blind randomized controlled trial of 6g FO (3.55 g/day of n-3 PUFAs) versus olive oil (control) from mid-pregnancy until 3 months postpartum. Eligible females had singleton pregnancies at 12-20 weeks of gestation, and BMI ≥25 kg/m2. The primary outcome was infant body fat percentage (DXA scans) at 2 weeks of age. Secondary outcomes included maternal metabolic markers during pregnancy, infant anthropometry at 2 weeks and 3 months of age, and metabolic markers at 3 months.

RESULTS: 129 mothers were randomized, and 98 infants had a DXA scan at 2 weeks.

PRIMARY OUTCOME: Imputed and non-imputed analyses showed no effects of FO supplementation on infant body fat percentage at age 2 weeks.

SECONDARY OUTCOMES: There were no treatment effects on infant outcomes at 2 weeks, but FO infants had higher BMI z-score (p=0.025) and ponderal index (p=0.017) at age 3 months. FO supplementation lowered maternal triglycerides by 17% at 30 weeks of pregnancy (p=0.0002) and infant triglycerides by 21% at 3 months of age (p=0.016), but did not affect maternal or infant insulin resistance (HOMA-IR). The rate of emergency caesarean section was lower with FO supplementation [aRR=0.38 (95%CI 0.16, 0.90); p=0.027].

CONCLUSIONS: FO supplementation of mothers with overweight or obesity during pregnancy did not impact infant body composition. There is a need to follow-up the offspring to determine whether observed metabolic effects persist.

CLINICAL TRIAL REGISTRY: NumberThis study was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12617001078347p). In addition, the Universal Trial Number, WHO, has been obtained (U1111-1199-5860).

PMID:36781129 | DOI:10.1016/j.ajcnut.2023.02.007