Asthma, Gestational Diabetes, and Adverse Perinatal Outcomes: A Population-Based Obstetrics Records Analysis

Asthma and gestational diabetes mellitus (GDM) are prevalent in pregnancy, with asthma previously associated with an increased GDM risk. Each independently increases the risk of adverse perinatal outcomes, but the effect of dual exposure is unknown.

To compare clinical, demographic, and perinatal outcome data between women with and without asthma, who do and do not develop GDM.

Data for singleton births to mothers aged 18 years or older were extracted from electronic records across 2 Australian Health Districts (2018-2020). The effects of asthma and/or GDM on perinatal outcomes were estimated using generalized estimating equations.

Of 40,149 pregnancies, 9.6% had asthma only, 9.6% had GDM only, and 1.4% had asthma and GDM. Asthma was not associated with GDM risk, following adjustment for confounders (adjusted relative risk [aRR] 1.04; 95% confidence interval [95% CI] 0.96-1.13). Compared with neither exposure, asthma and/or GDM was associated with an increased risk for each cesarean birth and infant respiratory distress. Asthma was also associated with an increased risk of preterm birth (aRR 1.15; 95% CI 1.03-1.29), low birth weight (aRR 1.15; 95% CI 1.03-1.29), and congenital anomalies (aRR 1.15; 95% CI 1.03-1.29). There was also an increased risk of hypertensive disorders of pregnancy (aRR 1.36; 95% CI 1.05-1.77) with dual exposure. No multiplicative interactions between asthma and GDM were detected.

Asthma and/or GDM increased the risk of adverse perinatal outcomes, but no synergistic effect was observed for asthma+GDM exposure. Asthma was not associated with an increased risk of GDM after adjusting for important confounders, including obesity.