Gestational Weight Gain and Different Degrees of Preterm Birth: A Hospital-Based Study in Chinese Singleton Pregnancies.

AIM: The link between gestational weight gain and preterm birth remains inconclusive. The present study examines the association between gestational weight gain (GWG) and preterm birth among the Chinese population. DESIGN: A retrospective observational study design. METHODS: Data was from a hospital-based sub-study of the physical growth and development survey for Chinese newborns with different gestational ages, which was conducted from July 2015 to August 2017. Singleton newborns aged from 24 to 42 + 6 weeks' gestation and their mothers were investigated. A self-designed questionnaire was used for the collection of information. 3203 participants were included in the analysis and a logistic regression model was adopted to explore the association of GWG and different degrees of preterm birth and odds ratios and 95% CI were estimated. RESULTS: The mean GWG in the preterm group was significantly lower than that in the term group (13.00 ± 4.87 vs 15.72 ± 4.88 kg). After adjusting for potential confounders, the odds ratio of preterm birth was 2.13 (95% CI: 1.62-2.78) for mothers with low GWG and 0.42 (95% CI: 0.32-0.56) for those with excess GWG in comparison with those with adequate GWG. The odds ratio of low GWG was about 4.06 (95% CI: 2.87-5.72) for very preterm birth, 2.14 (95% CI: 1.47-3.10) for moderate preterm birth and 1.40 (95% CI: 1.03-1.91) for late preterm birth. The odds ratio of excess GWG was about 0.36 (95% CI: 0.24-0.54) for very term birth, 0.38 (95% CI: 0.25-0.57) for moderate preterm birth and 0.47 (95% CI: 0.35-0.64) for late preterm birth. PATIENT OR PUBLIC CONTRIBUTION: Adverse impact of low GWG was dependent on the degree of preterm birth. Weight management and health education during pregnancy in maternal nursing practice should focus on the appropriate increase of GWG against preterm birth.