Associations between gestational weight gain and adverse pregnancy outcomes: a prospective cohort study

Background: Most studies on gestational weight gain (GWG) and pregnancy outcomes have focused on Western populations, leaving a gap in knowledge about the applicability of their findings to Asian women. Similarly, most investigations have utilised recommendations created by the US Institute of Medicine, with few using the Chinese GWG recommendations. We aimed to assess the associations between GWG, evaluated according to the Chinese recommendations, and adverse pregnancy outcomes, as well as to explore whether prepregnancy body mass index (BMI) or maternal age modified these associations. Methods: ). We used logistic regression models to estimate odds ratios (ORs) for adverse pregnancy outcomes. Results: Among 10,638 pregnant women, 13.3%, 54.3%, and 32.4% had insufficient, adequate, and excessive GWG, respectively. After adjusting for confounders, excessive GWG was associated with higher odds for caesarean delivery (OR = 1.38; 95% confidence interval (CI) = 1.26-1.53), macrosomia (OR = 1.77; 95% CI = 1.44-2.17), being large for gestational age (OR = 1.66; 95% CI = 1.38-1.99), and neonatal ward admission (OR = 1.35; 95% CI = 1.09-1.67), while insufficient GWG was associated with increased odds of being small for gestational age (OR = 1.48; 95% CI = 1.17-1.88). There was a significant interaction between GWG and maternal age in relation to the odds of caesarean delivery (P-value for interaction = 0.034). Women aged ≥ 35 years with excessive GWG had the highest odds of caesarean delivery (OR = 2.72; 95% CI = 2.27-3.24), compared with women aged <35 years with adequate GWG. Conclusions: Excessive GWG was associated with higher odds of caesarean delivery, macrosomia, large for gestational age, and neonatal ward admission, while insufficient GWG was associated to higher odds of small for gestational age.