Two common conditions in pregnancy, preeclampsia and gestational hypertension, may increase the risk of future diabetes, according to a study of more than one million women.

The study was conducted by a team of researchers led by Denice Feig, from the University of Toronto, Canada and was published in the journal PLOS Medicine.

Preeclampsia is a condition in which pregnant women experience high blood pressure, protein in their urine, and fluid retention. Gestational hypertension is high blood pressure linked to pregnancy.

The authors discovered that these two conditions can double the risk of developing diabetes several years after pregnancy.

The scientists also found that when those two conditions are combined with gestational diabetes – diabetes only linked to pregnancy, a known risk factor for future diabetes – preeclampsia or gestational hypertension were associated with an additional increase in the risk of future diabetes over and above the 13-fold rise that results from gestational diabetes alone.

A prior report indicated that about one-third of pregnant women in the U.S. are not screened for gestational diabetes.

These results are critical, the authors explained, because they focus on novel risk factors for diabetes, indicating that doctors should be conscious of the need to screen for diabetes in females with a history of preeclampsia or gestational hypertension.

For the purpose of the study, the experts used a comprehensive health database in Canada to identify all women giving birth in an Ontario hospital between April 1994 and March 2008 who had gestational hypertension, preeclampsia, or gestational diabetes.

Using the Ontario Diabetes Database, they recorded whether these females developed diabetes 180 days after delivery until March 2011.

The analysis included 1,010,068 pregnant women, of whom:

  • 27,605 had only gestational hypertension
  • 22,933 had only preeclampsia
  • 30,852 had only gestational diabetes
  • 2,100 had both gestational diabetes and gestational hypertension
  • 1,476 women had gestational diabetes and preeclampsia

The team reported that overall, 35,077 women (3.5%) developed diabetes in the follow-up period.

The increased risk of future diabetes was:

  • 1.95 times higher in women with gestational hypertension alone
  • 2.08 times higher in those with preeclampsia alone
  • 12.77 times higher in those with gestational diabetes alone

However, when combined with gestational diabetes, the probability increased to:

  • 18.49 times higher for gestational hypertension
  • 15.75 times higher for preeclampsia

The researchers said:

“In this large, population-based study, we found that the presence of either preeclampsia or gestational hypertension during pregnancy were strong predictors for the development of diabetes years following the pregnancy, and the presence of preeclampsia or gestational hypertension in a woman with a history of gestational diabetes, increased the risk of diabetes over and above that observed with gestational diabetes alone.”

“These findings have important implications for maternal health, especially given the increase in obesity-related diseases,” they added.

Women who experienced preeclampsia or gestational hypertension during their pregnancy should notify their doctors in order to receive preventative counseling and more attentive screening for diabetes, they concluded.

Written by Sarah Glynn