Type 2 diabetes linked to increased perinatal mortality risk

Type 2 diabetes linked to increased perinatal mortality risk | Image Credit: © emiliau - © emiliau - stock.adobe.com.

Introduction

The odds of perinatal mortality are increased further by type 2 diabetes (T2D) in pregnancy compared with other forms of pregnancy, according to a recent study published in the American Journal of Obstetrics & Gynecology.

A rapid increase has been reported in the presence of early onset T2D, linked to significant declines in glycemic control and increased complication risks. Non-White women living in deprived communities are disproportionately impacted, leading to greater impacts on reproductive-aged populations.

“However, data on other adverse outcomes is conflicting,” wrote investigators. “Some data suggests an increase in the rates of stillbirth, major congenital malformations, and perinatal deaths in T2D and some demonstrate no difference in these outcomes compared to [type 1 diabetes (T1D)].”

Study methodology

To determine the impact of T2D on pregnancy outcomes, investigators conducted a systematic review and meta-analysis. Outcomes were compared to other forms of pregnancy such as T1D and gestational diabetes mellitus (GDM). Articles were identified through a systematic search of the PubMed database.

Eligibility criteria included being published in English between January 1, 2009, and January 1, 2024. Titles and abstracts were assessed by 2 independent investigators, with a third consulted to resolve discrepancies. This process was followed by full-text evaluation.

Studies about known T2D diagnosed before pregnancy were included in the analysis. Two independent authors extracted relevant study data, including year of publication, country of study, maternal background characteristics, and outcomes of interest.

Outcomes and study population

The number of congenital malformation events, stillbirths, neonatal mortality, perinatal mortality, large for gestational age (LGA), macrosomia, and small for gestational age (SGA) were reported as primary outcomes. Secondary maternal outcomes included diabetic ketoacidosis, hypoglycemic coma, preeclampsia, pregnancy-induced hypertension, and termination of pregnancy.

There were 62 studies included in the final analysis. Across these studies, there were 84,421 pregnancies impact by T2D, 34,751 by T1D, 243,243 by GDM, and 5,398,613 with no diabetes listed as controls. An older age, increased weight, and shorter duration of diabetes was reported in the T2D group vs T1D, GDM, and control patients.

Study findings

Chronic hypertension rates were 17.1% in the T2D group, 7.6% in the T1D group, 2.7% in the GDM group, and 0.7% in controls. T2D patients reported lower rates of diabetes-related microvascular complications and delivery at an earlier gestational age.

The risk of having an LGA baby was reduced among T2D patients vs T1D patients, with an odds ratio (OR) of 0.51. However, the OR for SGA was 2.52, indicating an increased risk among this population.

Neonatal mortality and perinatal mortality risks were also increased, with ORs of 1.53 and 1.31, respectively. The average weight of infantes was reduced by 80.20 g among infants of T2D patients vs T1D patients.

T2D patients also had increased risks compared to GDM patients. ORs for congenital anomalies, an LGA baby, perinatal mortality, and stillbirth were 1.91, 3.49, 3.96, and 16.55, respectively. Significant differences in birthweight were not reported between these populations.

When compared with controls, the risks of congenital anomaly, perinatal mortality, and stillbirth were increased among T2D patients, with ORs of 1.76, 4.18, and 7.27, respectively. The average weight of babies from T2D patients was increased by 27.91 g vs controls.

Most secondary outcomes did not differ between T2D and T1D pregnancies. Compared to GDM patients, T2D patients more often presented with pregnancy-induced hypertension, preeclampsia, cesarean section, and preterm birth.

Implications

These results indicated increased odds of perinatal mortality among pregnant patients with T2D vs other forms of diabetes. Investigators recommended additional research to evaluate the sources behind these poorer pregnancy outcomes.

“The fact that T2D is increasingly common in women having children highlights that clinicians, researchers, and policy makers need to be aware of these increased risks and work collaboratively with patient groups to optimize pregnancy outcomes and reduce longer term health inequalities,” wrote investigators.

References

1. Clement NS, Abul A, Farrelly R, et al. Pregnancy outcomes in type 2 diabetes: a systematic review and meta-analysis. American Journal of Obstetrics & Gynecology. 2025. doi:10.1016/j.ajog.2024.11.026
2. Xie J, Wang M, Long Z, et al. Global burden of type 2 diabetes in adolescents and young adults, 1990-2019: systematic analysis of the Global Burden of Disease Study 2019. BMJ. 2022;379:e072385. doi:10.1136/bmj-2022-072385