Maternal dietary patterns during pregnancy and preterm delivery: a large prospective cohort study in China

Background: Evidence about the associations between maternal dietary patterns and preterm delivery is scarce in Eastern countries. The purpose of this study was to examine the associations between maternal dietary patterns during pregnancy and preterm delivery in a Chinese population.

Methods: A total of 7352 mothers were included in the Born in Guangzhou Cohort Study, a prospective study in China. A validated self-administered food frequency questionnaire (FFQ) was used to assess maternal diet at 24-27 weeks of gestation. Dietary patterns were identified by cluster analysis. Gestational age was obtained from routine medical records. Preterm delivery was defined as delivery before 37 completed weeks of gestation, and was further classified into spontaneous and iatrogenic preterm delivery, and also early/moderate and late preterm delivery. Associations between dietary patterns and preterm delivery outcomes were assessed using logistic regression analyses.

Results: Six dietary patterns were identified, including 'Milk', 'Cereals, eggs, and Cantonese soups', 'Meats', 'Fruits, nuts, and Cantonese desserts', 'Vegetables', and 'Varied'. There were 351 (4.8%) preterm deliveries in this study population. Among those of preterm delivery, 16.2 and 83.8% were early/moderate and late preterm delivery, respectively. Compared with women of 'Vegetables' pattern, those of 'Milk' pattern had greater odds of overall preterm delivery (adjusted odds ratio [OR] 1.59, 95% confidence interval [CI] 1.11, 2.29, p < 0.05), spontaneous preterm delivery (adjusted OR 1.73, 95% CI 1.14, 2.62, p < 0.05) and late preterm delivery (adjusted OR 1.73, 95% CI 1.08, 2.62, p < 0.05); those of 'Cereals, eggs, and Cantonese soups' and 'Fruits, nuts, and Cantonese desserts' patterns had greater odds of late preterm delivery (adjusted OR 1.54, 95% CI 1.01, 2.35 for 'Cereals, eggs, and Cantonese soups', adjusted OR 1.61, 95% CI 1.04, 2.50 for 'Fruits, nuts, and Cantonese desserts', respectively).

Conclusion: Maternal diet with frequent consumption of milk and less frequent consumption of vegetables during pregnancy might be associated with increased odds of preterm delivery. Future interventions should investigate whether increasing vegetable intake reduces preterm deliveries.