Effects of aerobic exercise and antioxidant micronutrients on leptin levels in pregnancy: a sub-analysis from a double-blinded randomised controlled trial

Hyperleptinemia is associated with pregnancy complications. We assessed the effects of aerobic exercise, antioxidant micronutrient supplementation (AMS), and their combination on leptin levels during pregnancy. Healthy pregnant women were randomized to four groups: exercise (n = 19), AMS (zinc/magnesium/tocopherol/vitamin C/niacin) (n = 19), exercise plus AMS (n = 19), and controls (n = 20). Leptin levels were measured at 16–20 and 32–36 gestational weeks. Fat mass percentage (FM%) and high-sensitivity C-reactive protein (hs-CRP) were secondary outcomes. No significant baseline differences were observed across groups. Post-intervention leptin levels were significantly lower in the exercise group compared to controls [Geometric mean (95% CI): 24 (20–28.8) vs. 33.8 (26.9–42.3), p = 0.028]. No significant differences were found for the other interventions or for FM% and hs-CRP. Leptin increased in all groups (p < 0.05) except the exercise group (p = 0.682). In conclusion, aerobic exercise prevented leptin elevation during pregnancy, independently of fat mass changes. AMS attenuated this benefit when combined with exercise.