Grandmaternal and maternal age difference at delivery with maternal pregnancy cardiometabolic disorders: A cross-sectional study from Grandmothers, Mothers, and Their Children’s Health study

As the trend in delayed childbearing continues to rise, the association of the age difference between grandmothers and mothers at delivery, reflecting intergenerational reproductive age dynamics, with maternal pregnancy cardiometabolic disorders (CMDs) remains under-examined. To explore whether a larger age difference between grandmothers and mothers at delivery is associated with an increased risk of maternal pregnancy CMDs. This retrospective cross-sectional study was conducted based on the “Grandmothers, Mothers, and Their Children’s Health (GMATCH)” study, which collected data from 2242 pairs of three-generation women within family in Huai’an city, China. Multivariable logistic regression model was utilized to estimate the association between age difference and pregnancy CMDs. Restricted cubic splines were used to account for potential nonlinear relationships between continuous age differences and pregnancy CMDs. Based on data from 2235 grandmother-mother pairs, we noted an increase in the median delivery age from 24 years in grandmothers to 28 years in mothers, with age differences ranging from − 21 to 21 years (median: − 4, interquartile range: − 7, 0). A delivery age difference of ≤ − 9 years was associated with pregnancy CMDs. Dose-response analysis indicated that a larger age difference between grandmaternal and maternal delivery was associated with a higher risk of CMDs, although this association was attenuated when maternal age at delivery was considered. Our study underscores the potential importance of intergenerational delivery age differences in pregnancy CMD risk. However, further studies with larger sample sizes are required to validate these findings. Healthcare providers should consider both maternal and grandmaternal age when evaluating risk factors for CMDs.