Increasing Trends in Maternal BMI, CS and Macrosomia in First-Time Mothers: What was the Impact of the Pandemic?.

Abstract

Introduction: The impact of the pandemic on maternal weight and perinatal outcomes in first-time mothers is unknown. Aim(s): We compared perinatal outcomes in first-time mothers, with and without pregnancy exposure to the pandemic, and hypothesised that an increased rate of BMI >=25 would influence perinatal outcomes. Method(s): Multi-centre retrospective study involving births from all 12 Melbourne public maternity hospitals from January 2018 to March 2022. All first-time mothers to a singleton infant in cephalic presentation at term were included. Outcomes included the rates of caesarean section (CS) and macrosomia (birthweight >=4000 g). A p <0.05 was considered statistically significant. Interrupted time series analysis was performed to analyse trends before and after the onset of the pandemic. Result(s): We analysed 51,195 births from first-time mothers. The proportion of mothers with BMI >=25 was greater in the pandemic cohort (45.82% vs 44.57%, p = 0.005) as was the proportion of infants with macrosomia (8.55% vs 7.99%, p = 0.12). The CS rate was greater in the pandemic cohort (33.09% vs 30.80%, p < 0.005). The interrupted time series analysis demonstrated no significant additional effect of the pandemic on the pre-existing upward trends in macrosomia and CS. Discussion(s): Our results show that pandemic exposed first-time mothers had higher rates of BMI >=25, macrosomia and CS. However, these higher rates appeared to be a continuation of long-standing upward trends independent of the pandemic. These upward trends are forecast to continue beyond the study period, with long-term implications for population health.