Association between prepregnancy body mass index or gestational weight gain and adverse pregnancy outcomes among Chinese women with gestational diabetes mellitus: a systematic review and meta-analysis

Objective The association between prepregnancy body mass index (BMI) or gestational weight gain (GWG) and adverse pregnancy outcomes among Chinese women with gestational diabetes mellitus (GDM) is unknown. This study aims to evaluate such association by synthesising the evidence. Design Systematic review and meta-analysis. Data sources PubMed, Web of Science, Scopus, EMBASE, China Biology Medicine disc, China National Knowledge Infrastructure, Wangfang, and China Science and Technology Journal Database searched from inception to 11 August 2023. Eligibility criteria Prospective cohort studies, retrospective cohort studies and case–control studies estimating the relationship of abnormal prepregnancy BMI (including underweight, overweight or obesity) or inappropriate GWG (including excess GWG or insufficient GWG) with adverse pregnancy outcomes of interest were included. Outcomes included macrosomia, caesarean section, preterm birth, gestational hypertension, large for gestational age (LGA) and small for gestational age (SGA). Data extraction and synthesis Two reviewers independently selected studies, extracted the data and assessed the risk of bias. OR estimate and its 95% CI were pooled using Stata software fixed-effect model. Subgroup analysis, meta-regression and sensitivity analysis were performed to ensure credibility of the results. Results Twenty-three studies (eighteen retrospective cohort studies, three prospective cohort studies and two case control studies) involving 57 013 Chinese women with GDM were identified. Meta-analysis results showed that compared with GDM women with normal weight, GDM women with underweight were at a higher risk of SGA (OR=1.79 (1.54 to 2.07), five studies involving 31 967 women); women with overweight had higher risks of macrosomia (OR=1.65 (1.49 to 1.82), eleven studies involving 41 683 women), caesarean section (OR=1.48 (1.38 to 1.59), ten studies involving 34 935 women), preterm birth (OR=1.27 (1.13 to 1.43), eight studies involving 38 295 women) and LGA (OR=1.73 (1.54 to 1.95), seven studies involving 31 342 women) and women with obesity had higher risks of macrosomia (OR=2.37 (2.04 to 2.76), eleven studies involving 41 683 women), caesarean section (OR=2.07 (1.84 to 2.32), nine studies involving 34 829 women), preterm birth (OR=1.31 (1.09 to 1.57), eight studies involving 38 295 women) and LGA (OR=2.63 (2.15 to 3.21), six studies involving 31 236 women). Regard to GWG, compared with Chinese GDM women with sufficient GWG, GDM women with excessive GWG had higher risks of macrosomia (OR=1.74 (1.58 to 1.92), twelve studies involving 40 966 women), caesarean section (OR=1.44 (1.36 to 1.53), nine studies involving 36 205 women) and LGA (OR=2.12 (1.96 to 2.29), twelve studies involving 42 342 women); women with insufficient GWG conversely had higher risks of preterm birth (OR=1.59 (1.45 to 1.74), nine studies involving 37 461 women) and SGA (OR=1.38 (1.27 to 1.51), ten studies involving 41 080 women). Conclusions For Chinese women with GDM, abnormal prepregnancy BMI or inappropriate GWG were related to higher risks of many adverse pregnancy outcomes. Therefore, medical staff should pay more attention to the weight management of GDM women during pregnancy.