Good news pregnant ladies: A new study shows a link between giving birth and long-term health benefits, including longer life. Here's why it pays to be a mom...
It might seem like being pregnant has taken a toll on your body, but in reality, having a baby might benefit your future health. A study published in journal BMC Medicine looked at different reproductive factors in women, like the start of menstruation, breastfeeding, using oral contraceptives and giving birth, on the risk of death from any cause. The results showed that having babies, as well as breastfeeding, actually seem to reduce women's risk of death in general, and specifically from cancer and cardiovascular disease. Although the benefits of some of these reproductive factors have been assessed separately before, this new research is unique because it looked at all of them together.
Reproductive factors that impact health
Researchers analyzed data from over 300,000 women in 10 countries who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The women were followed for almost 13 years, and over that time there were 14,383 deaths, including almost 6,000 from cancer and 2,400 from circulatory system diseases. When they looked at the women's reproductive histories, "women who had given birth had a 20 percent reduced risk of death than those who had not," says lead author Melissa Merritt, Ph.D., a research fellow in Cancer Epidemiology at Imperial College London. "It was also found that there was an eight percent reduced risk of death in women who had breastfed compared to those who did not," although the duration of breastfeeding was not significant. Other factors that reduced risk were the use of oral contraceptives and a later start of menstruation.
Merritt and her colleagues then delved deeper into the correlations between giving birth and eventual health outcomes. They discovered it was more important whether a woman had had any children than how many she had. "When we assessed the number of children that a woman had given birth to [among women who've had children], we did not see any association with mortality risk," she says. However, there was a reduction in the specific risk of breast cancer among women who had more than one child; but there was a greater risk of circulatory disease among women who'd had more than four children, possibly because of an increase in blood pressure and body weight by numerous pregnancies.
Interestingly, the age at which a woman had children did influence the findings. "Those who had given birth early or later in life had a higher risk of death compared to those who gave birth between the ages of 26 and 30 years old," Merritt says. The reason for this narrow window, though, is unknown. Noting that it could be a "chance finding," Merritt says additional studies are needed to confirm the age factor and figure out the reasons why.
The hormone effect
All of these results, though, beg the question: Why does having a baby, along with breastfeeding and taking the pill, lessen your chance of illness later in life? "Hormonal mechanisms may explain the association of a reduced risk of death with breastfeeding, having given birth and using oral contraceptives, as these factors are associated with changes in hormone levels," Merritt says. Among other hormones, it may have something to do with estrogen—both breastfeeding and the pill reduce estrogen levels, and although pregnancy raises them, it also raises progesterone, which might offset estrogen's effects.
Further studies are needed before we can say for sure exactly what role hormones play, and how each part of a woman's reproductive profile impacts her long-term health. "Reproductive factors are connected to each other because they influence a woman's hormone levels, but each reproductive characteristic has a unique influence on hormonal changes," Merritt says. But, "due to the observational nature of this study, it is not possible to conclude that these various reproductive factors are the cause of the reduction in risk that has been seen."
Merritt says she doesn't necessarily advise women to use these results in deciding if and when to get pregnant or breastfeed. "It is still too early to directly translate the findings from this study to make recommendations for family planning," she says. But, if researchers can figure out how hormonal changes impact health, they might eventually be able to develop a drug that can mimic those effects— so a woman who hasn't given birth or breastfed, for example, could still reap the benefits. "Additional studies are needed to confirm these findings and clarify the mechanisms that link these risks," Merritt says, "which could then help in the development of new strategies to improve the long-term health of women."