Pregnancy Outcomes in Women with Type 1 Diabetes by Socioeconomic and Mental Health Disadvantages

Aim: To examine whether individual-level measures of socioeconomic or mental health disadvantages are associated with preterm delivery and extreme large for gestational age (eLGA) among women with type 1 diabetes. Methods: Nationwide register-based study of singleton pregnancies among women with type 1 diabetes, 1997– 2021. Disadvantages included family poverty (disposable income < 50% of national median) and, for either parent, low educational level (≤primary school), unemployment (cash/disability benefits), or poor mental health (≥ 1 prepregnancy psychiatric diagnosis). Outcomes were preterm delivery (< 37 weeks) and eLGA (birthweight ≥ 97.5th percentile). We estimated absolute risk (AR) and crude and adjusted relative risks (aRR), adjusting for parental immigration status and maternal birth year. Sensitivity analyses were stratified by prepregnancy HbA1c (< 53/≥ 53 mmol/mol). Results: Among 5478 pregnancies, AR of preterm delivery and eLGA were 32.5% and 36.0%, respectively, and 40.1% experienced ≥ 1 disadvantage, ranging from 5.6% having family poverty to 18.9% having low paternal educational level. Higher aRRs of preterm delivery were found across all measures of disadvantage, ranging from 1.23 (1.00;1.45) to 1.48 (1.28;1.68). We observed a non-significant trend toward lower risk of eLGA with all disadvantages (aRRs ranging from 0.82 (0.64;1.00) to 1.01 (0.84;1.18)). Stratification by prepregnancy HbA1c showed basically unchanged aRRs but widened confidence intervals. Conclusion: Among women with type 1 diabetes, socioeconomic or mental health disadvantages were associated with higher risk of preterm delivery, but not eLGA, regardless of prepregnancy HbA1c level. These findings underscore the need for targeted interventions to address social and mental health disparities in order to reduce preterm birth risk among women with type 1 diabetes. Plain Language Summary: Pregnancies where the mother has type 1 diabetes have a higher risk of complications. Social and mental health disadvantage may influence pregnancy outcomes in general, but we know little about their role for this group. This study aimed to improve our understanding of the relationship between disadvantage and pregnancy complications among women with type 1 diabetes. We used national health registers to study 5478 singleton pregnancies where the mother had type 1 diabetes between 1997 and 2021. We looked at whether social and mental health disadvantage were linked to two outcomes: preterm delivery (before 37 weeks of pregnancy) and having very large babies. We evaluated the disadvantages family poverty, low education, unemployment, or a diagnosed mental health condition in either parent. About one in three pregnancies ended in a preterm birth, and one in three babies were very large at birth. About 40% of pregnancies experienced at least one social or mental health disadvantage. Pregnancies that experienced disadvantage had a higher risk of preterm delivery, but not of having very large babies. This was independent of other risk factors for complications among pregnancies with type 1 diabetes such as mothers age, smoking and immigration status as well as the mothers blood glucose levels before pregnancy. Social and mental health disadvantage carries a higher risk of preterm delivery in pregnancies where the mother has type 1 diabetes. Future research should investigate how to mitigate this inequality in health care.