We are aware of no study that examined the effects of omega-3 fatty acid supplementation on insulin metabolism and lipid profiles in gestational diabetes (GDM). This study was designed to assess the effects of omega-3 fatty acid supplementation on insulin concentrations and lipid profiles among pregnant women with GDM.

This randomized, double-blind, placebo-controlled clinical trial was performed among 56 women with GDM. Subjects were randomly assigned to receive either 1000 mg omega-3 fatty acid supplements containing 180 mg eicosapentaenoic acid and 120 mg docosahexanoic acid (n = 28) or placebo (n = 28) for 6 weeks. Fasting blood samples were taken at study baseline and after 6 weeks of intervention to quantify biochemical variables.

Although omega-3 fatty acid supplementation did not led to a significant change in serum insulin levels and HOMA-IR in omega-3 fatty acid group, we found a significant difference in changes in serum insulin levels (change from baseline: -1.5 ± 7.5 vs. +3.5 ± 8.5 μIU/mL, P = 0.02) and HOMA-IR (-0.4 ± 2.1 vs. +1.1 ± 2.4, P = 0.02) comparing the two groups. Furthermore, a significant reduction in serum high sensitivity C-reactive protein (hs-CRP) levels was seen after omega-3 fatty acid supplementation compared with placebo (-236.3 ± 1541.9 vs. 898.6 ± 2292.7 ng/mL, P = 0.03). Omega-3 fatty acid supplementation did not influence fasting plasma glucose, homeostatic model assessment-Beta cell function (HOMA-B), quantitative insulin sensitivity check index (QUICKI) and lipid profiles.

Omega-3 fatty acid supplementation in GDM women had beneficial effects on insulin resistance, however, it did not affect plasma glucose, HOMA-B, QUICKI and lipid profiles. Clinical registration number: as IRCT201312265623N16.