The Economic Burden of Gestational Diabetes and Body Mass Index Changes Between Pregnancies: A Retrospective Cohort Study.

Abstract

To determine associations between gestational diabetes mellitus (GDM) and body mass index (BMI) change between consecutive pregnancies, and hospital length of stay (LOS) and hospital costs. Retrospective cohort study. Two maternity hospitals, New South Wales, Australia. Women with two most recent singleton births between September 2011 and April 2019. Multivariable generalised linear models assessed association between GDM status (none, first only, second only, or both pregnancies) and BMI change (loss: < -1 kg/m²; stable: -1 to < 1; small gain: 1 to < 2; medium gain: 2 to < 4; or large gain: ≥ 4) in relation to second-birth LOS and hospital birthing costs. Costs were calculated using DRG codes and valued in 2024 AUD. Hospital LOS and hospital costs for the second birth. Of 11 157 women, 5% had GDM only in the first pregnancy, 9% only in the second and 8% in both. For the second birth, women with GDM in both pregnancies stayed 0.91 days longer (3.71 vs. 2.79 days) and incurred AU$1960 higher costs (AU$14680 vs. AU$12720) than those without GDM in either pregnancy. Adjusted models indicated GDM in both pregnancies was associated with a 21% longer LOS (95% CI: 16%-26%, p < 0.001) and 9% higher costs (7%-11%, p < 0.001). Large BMI gain (≥ 4 kg/m²) was associated with a 9% longer LOS (4%-14%, p < 0.001). Women with both GDM (both pregnancies) and large BMI gain had a 23% longer LOS (12%-36%, p < 0.001) and 9% higher costs (4%-15%, p < 0.001). GDM and interpregnancy BMI gain were associated with increased hospital stay and higher birthing-related hospital costs for the second birth. These findings underscore the importance of preventive strategies and supportive public health policies to reduce the burden of GDM and high BMI gain. Approaches such as nutritional counselling, lifestyle modification and physical activity programs are likely to support women planning a subsequent pregnancy after their index birth (first pregnancy or first pregnancy with GDM diagnosis).