Sarah J. Glastras

Summary Maternal obesity and gestational diabetes mellitus (GDM) prevalence are increasing, with both conditions associated with adverse neonatal outcomes. This review aimed to determine the risk of adverse outcomes in women with obesity and GDM, compared with women with obesity alone. A systematic search identified 28 eligible articles. Meta‐analysis was conducted using a random effects model, to generate pooled estimates (odds ratios, OR, or mean difference, MD). Compared with normal‐weight controls, women with obesity had increased risks of large for gestational age (LGA, OR 1.98, 95% CI: 1.56, 2.52) and macrosomia (OR 2.93, 95% CI: 1.71, 5.03); the latter's risk almost double in women with obesity than GDM. Birth weight (MD 113 g, 95% CI: 69, 156) and shoulder dystocia (OR 1.23, 95% CI: 0.85, 1.78) risk was also higher. GDM significantly amplified neonatal risk in women with obesity, with a three‐ to four‐fold risk of LGA (OR 3.22, 95% CI: 2.17, 4.79) and macrosomia (OR 3.71, 95% CI: 2.76, 4.98), as well as higher birth weights (MD 176 g, 95% CI: 89, 263), preterm delivery (OR 1.49, 95% CI: 1.25, 1.77), and shoulder dystocia (OR 1.99, 95% CI: 1.31, 3.03), when compared with normal‐weight controls. Our findings demonstrate that maternal obesity increases serious neonatal adverse risk, magnified by the presence of GDM. Effective strategies are needed to safeguard against neonatal complications associated with maternal obesity, regardless of GDM status.