For a study, researchers sought to describe stillbirths related to pregestational diabetes and gestational diabetes mellitus (GDM) in a large, prospective case-control research conducted in the United States. A secondary analysis of stillbirths was undertaken among patients recruited in a prospective, multisite, geographically, racially, and ethnically diverse case-control research in the United States. Singleton pregnancies with comprehensive diabetes status information and a complete postmortem examination were included. A conventional stillbirth evaluation process included postmortem evaluation, placental pathology, clinical testing at the discretion of the health care practitioner, and a suggested panel of tests. Stillbirth cases were assigned a possible cause of death using a standardized categorization technique. Demographic and delivery features of women with pregestational diabetes and gestational diabetes were compared to characteristics of women without diabetes in pairwise comparisons using 2 or two-sample t-tests, if applicable. Pregnancies with genetic disorders or significant fetal abnormalities were excluded from the sensitivity analysis.

Women with stillbirth and diabetes were more likely to be older than 35 years and have a higher body mass index, according to the primary study of 455 stillbirth cases. They were also more likely than nondiabetic women to suffer a gestational hypertension condition (28% vs 9.1%; P<.001). Pregnant women had higher large-for-gestational-age (LGA) neonates (26% vs 3.4%; P<.001). Pregnant women with pregestational diabetes (36%) had higher stillbirths than those with gestational diabetes (GDM) (52%). Maternal medical problems, such as pregestational diabetes and others, were more frequently recognized as a likely or plausible cause of death in stillbirths with maternal diabetes (43% vs 4%, P<.001) than in stillbirths without diabetes (43% vs 4%, P<.001).

Stillbirths in women with pregestational diabetes and GDM occurred later in pregnancy than in women without diabetes and were related to hypertensive disorders of pregnancy, maternal medical problems, and LGA.