Does trans fatty acid affect low birth weight? A randomized controlled trial

Objective: To evaluate the effect of low trans fatty acids (TFAs) dietary pattern during pregnancy on risk of low birth weight (LBW). Methods: : All pregnant women who received prenatal care with gestational age <8 weeks and aged ≤35 years were included in this randomized controlled trial study that took place in Tehran from December 2014 to August 2016. Women in the intervention group received individualized dietary pattern with TFAs content of < 1%; those in control group had dietary intake with no change on TFAs content. Dietary intakes were assessed by 3 non-consecutive 24-hour recalls at first prenatal care visit and at gestation age 13, 25 and 35 week. Hazard ratio was calculated using Cox proportional‐hazards models. Incidence and hazard ratio (95% CI) for low birth weight based on multivariable adjusted models were calculated. Result: Of the 800 women (n=407 in control and n=393 in intervention groups), 108 (13.5%) women were diagnosed with low birth weight. The incidence of LBW in intervention group was 12% and in control group was 19%. After multivariable adjustment for confounders, the hazard ratios for incident low birth weight in intervention group were 0.65 (0.44-0.96). Kaplan-Meier plot showed significant difference between two groups in incidence of LBW. Conclusion: Intake of low TFAs dietary pattern during pregnancy reduced risk of LBW. Trial registration The trial has been registered in the Iranian Registry of Clinical. Registration number: IRCT2016092729902N3. Registered 8 November 2016, https://en.irct.ir/trial/23919