Gestational Weight Gain
Six studies reported gestational weight gain according to NAM guideline as an outcome.33,47-51 Pooled results demonstrated no statistically significant association between diet quality and excessive (OR: 0.91; 95 CI: 0.76, 1.10; I2 = 59%; P-heterogeneity = 0.03; Figure 2) or inadequate gestational weight gain (OR: 0.90; 95 CI: 0.70, 1.17; I2 = 80%; P-heterogeneity < 0.01; Figure S1). Results were consistent in the sensitivity analysis where the moderate quality study33 was excluded (Table S6). Due to small number of studies, we were unable to detect the covariate that could explain the observed heterogeneity (Table S7).
Three studies reported gestational weight gain as a continuous outcome.40,52,53 A Meta-analysis could not be performed because effect estimates were not available for one of the studies52. Rohatgi et al. found a strong association between HEI-2010 and GWG (p=0.0011), but no detailed effect estimates were reported52. Fulay et al. found that in women who were obese before pregnancy, each one-unit increment in the DASH diet score was associated with 0.19 (95% CI: 0.05, 0.34) kg higher GWG from the time of dietary assessment to delivery53. In a small study of 41 women, Grandy et al. did not find a statistically significant association between HEI-2010 and GWG40.