Interaction Between Maternal Obesity and Metabolic Dysfunction in Gestational Hypertension and Preeclampsia: A Prospective Birth Cohort Study

This prospective birth cohort study, conducted in China with 21 893 singleton pregnant women, aimed to investigate the association between metabolic obesity phenotypes and the risks of gestational hypertension (GH) and preeclampsia (PE), as well as to explore the potential interaction between obesity and metabolic abnormalities in relation to these conditions. Participants were categorized according to their pre-pregnancy BMI and metabolic status into different obesity metabolic phenotypes. The diagnosis of GH and PE was based on blood pressure measurements, evidence of end-organ dysfunction, or proteinuria occurring after 20 weeks of gestation. The results indicated that, compared to metabolically healthy normal-weight women, those with metabolically unhealthy normal weight, metabolically healthy overweight/obesity, and metabolically unhealthy overweight/obesity all had significantly elevated risks for both GH (with adjusted odds ratios ranging from 1.77 to 3.89) and PE (adjusted ORs from 1.58 to 4.51). In contrast, metabolically healthy underweight women were found to have a lower risk of GH. Furthermore, an additive interaction was observed between overweight and metabolic unhealthiness, which increased the risk of GH by 1.15 times, representing a 28% relative excess risk. The combined risk for women exposed to both factors was 1.58 times greater than the risk associated with either factor alone. In conclusion, both metabolic abnormalities and overweight/obesity elevate the risks of GH and PE, and a significant interaction effect exists between these two factors.