High blood pressure in pregnancy increases risk of cardiomyopathy in later years

13th April 2016

Pregnant women who have high blood pressure and pre-eclampsia have an increased risk of developing dilated cardiomyopathy in later years, says a study from Denmark.

The figures were taken from a large registry involving one million Danish women.

It has long been known that pregnant women with these symptoms during pregnancy are more likely to develop peripartum (pregnancy-related) cardiomyopathy, but researchers were surprised the see that the increased risk of cardiomyopathy was still present years later.

In the study, published in the March issue of the Journal of the American Medical Association, 11% of all cardiomyopathy events occurred in women with a history of  high blood pressure in pregnancy, defined as severe preeclampsia, moderate preeclampsia, or gestational hypertension.

Rates of cardiomyopathy in all three of these groups were significantly higher than in women with normal blood pressure in pregnancy.

Limiting the analysis to dilated cardiomyopathy produced similar results suggesting that the associations may primarily be driven by dilated cardiomyopathy," the authors report.

The researchers used patient and birth registries to identify over one million women with two million pregnancies between 1978 and 2012. Of these, 76,108 were complicated by high blood pressure.

Senior research author Dr Heather Boyd, from the Statens Serum Institute, Copenhagen, emphasised that even though they identified an increased risk of cardiomyopathy, the absolute risk was small. Rates in women with a history of high blood pressure was just 14.6 to 17.3 cases per 100,000 person-years.

Dr Boyd said the strengths of the study lie in its size and the ability to determine what medications the women took and who was diagnosed with high blood pressure over the nearly 35 years of follow-up.