Interactive effects of gestational diabetes and high pre‐pregnancy body mass index on adverse growth patterns of offspring

Abstract Aims To examine the independent and interactive effects of maternal gestational diabetes mellitus (GDM) and high pre‐pregnancy body mass index (BMI) on the risk of offspring adverse growth patterns. Materials and Methods One thousand six hundred and eighty one mother‐child pairs were followed for 8 years in Tianjin, China. Group‐based trajectory modelling was used to identify offspring growth patterns. Logistic regression was performed to obtain odds ratios (ORs) and 95% confidence intervals (CIs) of GDM and high pre‐pregnancy BMI for offspring adverse growth patterns. Restricted cubic spline was used to identify cut‐off points. Additive interactions and multiplicative interactions were used to test interactive effects between GDM and high pre‐pregnancy BMI for adverse growth patterns. Results Four distinct growth patterns were identified in offspring, including normal growth pattern, persistent lean growth pattern, late obesity growth pattern (LOGP), and persistent obesity growth pattern (POGP). Maternal high pre‐pregnancy BMI was associated with LOGP and POGP (adjusted OR, 95% CI: 2.38, 1.74–3.25 & 4.92, 2.26–10.73). GDM greatly enhanced the adjusted OR of high pre‐pregnancy BMI for LOGP up to 3.48 (95% CI: 2.25–5.38). Additive interactions and multiplicative interactions between both risk factors were significant for LOGP but not for POGP. Conclusions Maternal high pre‐pregnancy BMI was associated with increased risk of LOGP and POGP, whereas GDM greatly enhanced the risk of high pre‐pregnancy BMI for LOGP.