Preterm Birth
Eight studies reported preterm birth as an outcome36,38,42,46,53,56,58,59. When results were pooled, pregnant women in the top tertile of diet quality scores had a lower risk of preterm birth compared to those in the bottom tertile (OR: 0.77; 95 CI: 0.66, 0.89; I2 = 16%; P-heterogeneity = 0.30; Figure 5). All studies were of high quality (NOS score ≥ 7) (Table S2). In the study of Saunders et al.38, prepregnancy BMI was found to be a strong effect modifier and the protective effect of good diet quality on preterm birth was stronger in overweight/obese women.