medwireNews: A Canadian research team has called for earlier identification of type 2 diabetes in pregnant women, after finding they are at elevated risk for perinatal mortality and other adverse outcomes compared with women with gestational diabetes mellitus (GDM) alone.
The study of nearly a million women who gave birth in the province of Ontario over a 13-year period revealed that 2.6% of those with GDM actually had undiagnosed type 2 diabetes, which was identified in the year after birth.
Women with undiagnosed type 2 diabetes had worse maternal and neonatal outcomes than those solely with GDM – such as perinatal mortality, pre-term birth, congenital abnormalities, neonatal intensive care unit admission, and neonatal hypoglycemia – with a magnitude comparable to that of women with pre-existing diabetes.
“The women in our study with undiagnosed type 2 diabetes were just as likely to have a primary care physician and also had more visits to their primary care physician prior to pregnancy [as] those with GDM alone, and therefore this represents missed opportunities for a diabetes diagnosis pre-pregnancy,” the researchers report.
“Also, many of them had chronic hypertension, which should alert caregivers to the increased risk of diabetes.”
The team analyzed provincial administrative healthcare data on 995,990 women with singleton pregnancies who delivered between April 2002 and March 2015.
Overall, 68,163 (6.8%) eligible women were diagnosed with GDM, with 1772 (2.6%) of these diagnosed with type 2 diabetes within a year postpartum. There were also 16,283 (1.6%) women who had type 1 or 2 diabetes diagnosed before pregnancy.
Women with undiagnosed type 2 diabetes had a 2.3-fold increased likelihood for perinatal mortality, compared with healthy women without diabetes, and a 2.1-fold increased likelihood of congenital abnormalities, after adjusting for multiple confounding factors.
They also had a 2.6-fold increased likelihood for preterm birth before 37 weeks, a 3.1-fold increased likelihood for admission to a neonatal intensive care unit, and a 405.9-fold increased likelihood for neonatal hypoglycemia compared with women without diabetes.
The risks for these outcomes in women with undiagnosed type 2 diabetes when compared with women with GDM alone were increased a significant 3.4-, 1.8-, 1.7-, 1.9-, and 1.9-fold, respectively.
“The strongest predictor of having undiagnosed type 2 diabetes was early GDM diagnosis at <20 weeks gestation,” note Denice Feig (University of Toronto, Ontario) and colleagues.
“Hypertensive disorders including chronic hypertension and gestational hypertension or pre-eclampsia were significant predictors of undiagnosed type 2 diabetes, particularly chronic hypertension. Other maternal predictors included having a history of GDM in a previous pregnancy, being in the lowest income quintile, and having ≥3 deliveries.”
Reporting in Diabetic Medicine, the team concludes: “Earlier identification of these women in pregnancy, preferably as soon as pregnancy is confirmed, with more aggressive treatment and surveillance, may improve such adverse outcomes.
“More efforts to diagnose these women before pregnancy are needed so that appropriate pre- pregnancy care can be given.”
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