A German study of over 11,500 women who had ever been pregnant, concluded that those who miscarried or had stillbirths had a substantially higher risk of heart attack later in life compared to those who had not.

The research was the work of Dr Elham Kharazmi, of the German Cancer Research Center in Heidelberg, Germany, and colleagues, and is published in the 1 December online first issue of the journal Heart.

Research suggests that miscarriage is a common complication of pregnancy, occurring in up to one in five pregnancies.

For this study, Kharazmi and colleagues analyzed data gathered over an average follow up of nearly 11 years, on 11,518 women aged between aged 35 and 66, who had been pregnant at least once, and who were part of the Heidelberg arm of the EPIC study.

EPIC (European Prospective Investigation into Cancer and Nutrition) is a large European study that has been tracking the impact of diet and lifestyle on diseases like cancer.

Kharazmi and colleagues were particularly interested in participants whose pregnancies had ended in miscarriages, abortion or stillbirths, and whether these were linked with higher risk of myocardial infarction (MI, heart attack) and stroke.

The results and analysis showed that:

  • 25% (2,876) of the women had had at least one miscarriage, 18% (2,053) at least one abortion and 2% (209) at least one stillbirth.

  • During the follow up period, there were 82 cases of heart attack (MI), and 112 of stroke (confirmed by the women’s medical records).

  • Of the women who had miscarried, 69 had had more than one miscarriage.

  • The women who had miscarried more than three times tended to weigh more; those who had had a stillbirth tended to be less physically active and were more likely to have diabetes and high blood pressure.

  • After adjusting for age, each stillbirth was linked to 2.65 higher risk of heart attack (95% confidence interval or CI for age-adjusted hazard ratio or HR ranged from 1.37 to 5.12).

  • After further adjusting for smoking, alcohol use, body mass index BMI, waist to hip ratio, physical activity, education, number of pregnancies, blood pressure, hyperlipidaemia and diabetes, this fell slightly to 2.32 higher risk of heart attack (95% CI 1.19 to 4.50).

  • After adjusting for age, recurrent miscarriage, that is having more than three miscarriages, was linked with about nine times higher risk of heart attack or MI (age-adjusted HR was 8.90, and 95% CI ranged from 3.18 to 24.90).
  • After further adjusting for the same potential confounders as in the stillbirth analysis, recurrent miscarriage was linked with about 5 times higher risk of heart attack (fully adjusted HR was 5.06, with 95% CI ranging from 1.26 to 20.29).

  • No significant links were found between abortion and heart attack or MI, and neither were any found between any type of pregnancy loss and stroke.

Kharazmi and colleagues concluded that these results suggest that women who experience spontaneous pregnancy loss, that is not including abortion, are at a substantially higher risk of heart attack (MI) in later life.

“Recurrent miscarriage and stillbirth are strong sex-specific predictors for MI and thus should be considered as important indicators for cardiovascular risk factors monitoring and preventive measures,” they wrote.

They also called for more studies to look into whether there are any risk factors common to pregnancy loss and cardiovascular disease.

“Pregnancy loss and risk of cardiovascular disease: a prospective population-based cohort study (EPIC- Heidelberg).”
Elham Kharazmi, Laure Dossus, Sabine Rohrmann, Rudolf Kaaks.
Heart, Published Online First 1 December 2010.
DOI:10.1136/hrt.2010.202226

Additional source: BMJ-British Medical Journal.

Written by: Catharine Paddock, PhD