Pregnancy losses linked to cardiovascular disease
New research from the University of Cambridge, UK, and the University of North Carolina in the US has found that women who experience pregnancy losses and do not go on to have children are at greater risk of cardiovascular disease, such as heart disease and stroke, compared with women who have only one or two children. The study also found that women who have five or more children are at increased risk of cardiovascular disease in later life.
Although most changes that occur during pregnancy are temporary, changes such as weight gain and accumulation of abdominal fat, higher levels of cholesterol, increased insulin resistance, and changes in the structure of the heart, are known to be risk factors for cardiovascular disease in the general population.
The researchers analysed data from more than 8,500 white and African-American women, aged 45-64 years in the US, including health service data on cardiovascular disease over a 30-year period and self-reported data on the number of pregnancies and births, and breastfeeding practices. Within the study population, 138 women reported having experienced pregnancy loss and having no live born children, 3,108 women had one or two live born children, 3,126 had three to four live born children, and 1,694 had five or more live born children.
The researchers found that women who experienced pregnancy loss and did not have any live born children were at 64 per cent greater risk of both coronary heart disease and 46 per cent greater risk of heart failure compared to women with one or two children. Women with five or more births were found to have a 38 per cent higher risk of having serious heart attack, regardless of how long they breastfed for.
According to the team, the link between cardiovascular risk and multiple births could be explained by a number of reasons. For example, repeated pregnancies could result in long-lasting changes within the body including weight gain, especially around the waist, and increased levels of cholesterol in the blood. Also, the number of children a woman has also includes other factors such as child-rearing, age at menopause and health conditions. This means it is unclear whether the increased risk of heart failure, coronary heart disease and heart attacks reflect the direct impact of repeated pregnancies, or the stressors associated with rearing multiple children, or both.
“Conditions such as heart disease and stroke together are the leading cause of death in women in the developed world and it is essential that we understand why this is the case,” said Dr Clare Oliver-Williams, a Junior Research Fellow at Homerton College who works at from the Department of Public Health and Primary Care at the University of Cambridge. “Our work suggests that there is a relation between cardiovascular disease risk and both pregnancy loss and having a large number of births.”