Having four or more children halves a woman’s chances of suffering a stroke.
Despite the stresses involved with having a large family, having four or more children might be good for women, a study has found.
Research involving 1300 women in California suggested those who had four or more children were one third less likely to due from cardiovascular disease. The majority of the effect seemed to result from the prevention of stroke, as mothers of large families were almost 50 per cent less likely to die of a stroke.
It may be that having higher levels of hormones associated with pregnancy circulating in the body for longer may leave lasting benefits on the body’s blood vessels, the researchers suggested.
It could also be that larger families offered greater social support to the mothers, or women that have more children are generally in better health, they said.
Lead author Marni Jacoobs of the University of California, in San Diego, wrote in the journal Fertility and Sterility: “In conclusion, women in this study had less CVD mortality risk if they had more than four pregnancies, with the strongest association observed for non-CHD CVD mortality.
“The mechanism by which this decreased risk occurs is unknown, however, it may reflect higher fertility in healthier women, the effect of prolonged exposure to higher levels of circulating oestrogen or other hormones during pregnancy, increased endothelial function during pregnancy, or the added social support from a larger family.”
Prof Donald Peebles, spokesman for the Royal College of Obstetricians and Gynaecologists said it was not clear why four or more children had such a protective effect.
He said, it might actually be that the childless women were at greater risk of cardiovascular disease than normal. He said the study did not examine the reasons those women did not have children and it may be that they were infertile which in itself could increase the risk of cardiovascular problems.
“We know that women who want to get pregnant and cannot are at greater risk of cardiovascular disease because of conditions such as polycystic ovaries,” he said.
Dr Bradley Van Voorhis, President of the Society for Reproductive Endocrinology and Infertility, said: “The physiological changes a woman experiences in pregnancy can have lasting effects on her health.
“In this study, a large, relatively healthy and affluent group of women showed a cardiovascular benefit to more than four pregnancies, but more research is needed to tell whether other factors, like the social support provided by a large family have an additional impact.”
Amy Thompson, Senior Cardiac Nurse at the British Heart Foundation, said: “We know that cardiovascular disease kills as many women as it does men, but they are affected in different ways and we do not fully understand why.
“One theory is that women are protected by their hormones up until the menopause. This study goes on to suggest that the number of pregnancies a woman has had can also have some effect on her cardiovascular risk later in life.
“Researchers found that women who had had four or more pregnancies had a reduced risk of cardiovascular disease, but they couldn’t say for sure why. Further research is needed before we jump to any conclusions.
“Regardless of our age, or pregnancy history, it is never too late to change our lifestyle and help to protect our hearts. We are all at risk, so quitting smoking, eating a healthy diet and getting regular exercise are great ways to start.”