Women bearing child late in life, live longer: Study

NEW DELHI, Jan 12: Women who postpone their pregnancy due to professional obligations are likely to live longer than their peers who beco...

NEW DELHI, Jan 12: Women who postpone their pregnancy due to professional obligations are likely to live longer than their peers who become mothers early in life, a study by Dutch and British scientists has revealed.

The study, conducted by Rudi Westendorp of Leiden and Thomas Kirkwood of the University of Manchester, has found that in humans there is a trade-off between longevity and reproductive success. Study of detailed records pertaining to the British aristocracy, computerised data that date back to 740 AD, containing the births, deaths and marriages of more than 33,000 people, including the ancestors of queens and hereditary British peers, show that women who had fewer children, or who bore their first children late in life, were more likely to live longer.

Conversely, women who died early were more likely to have borne children early in life. When the researchers considered post-menopausal women – those over 60 – they found that those who had the fewest children, and waited longer to have theirfirst child, lived the longest.

In fact, women who bore their first child in their 40s were more likely to become centenarians, the research revealed. Further, almost half of the women who lived to 81 or older had no children at all.

In course of their research, Westendorp and Kirkwood found that the mean age of death for women remained at about 45 until the beginning of the 18th century. The average life span, however, increased to an average of 68 years for those born between 1850 and 1875. In a period before the 18th century, the average number of offspring for a married woman was more than two, the figure touching a level of 2.8 in the 17th century during the reign of Elizabeth I. After that the average number of children declined to 1.5 by 1875.

This confirmed one bit of evolutionary theory: Individuals tend to pay for longevity with a lower reproductive success.

After initial studies on fruit flies had proved the above hypothesis, the researchers wanted to confirm whether the theory was valid incase of humans as, unlike humans, fruit flies have very short life spans.

Story continues below this ad

The researchers studied records pertaining to the British aristocracy, because blue-blooded families were "reasonably homogeneous and social deprivation has not interfered unduly with the chance of a long life".

The scientists looked at the potency of peers and found the same story: There was the same link between life span and male fertility, at least in the upper classes.