Women with many children, especially more than four or five, may look older as multiple pregnancies may accelerate the ageing of cells, claimed a new study.
According to the researchers, there is a good evidence to show that having more children can increase the risk of certain diseases and shorten lifespan.
Cellular ageing was accelerated by six months to two years for each additional pregnancy.
"Our study points to cellular changes during pregnancy, possibly related to adaptive changes in the mother's immune system as a possible explanation," said Christopher Kuzawa from the Northwestern University in the US.
For the study, published in the journal Scientific Reports, the team collected data from around 3,200 women aged between 20 to 22 years, looking at two separate markers of cellular aging, that is, telomere length -- protective caps at the end of DNA strands and epigenetic age.
"Telomere length and epigenetic age are cellular markers that independently predict mortality, and both appeared 'older' in women who had more pregnancies in their reproductive histories," added Calen Ryan from the varsity.
"Even after accounting for other factors that affect cellular aging, the number of pregnancies still came out on top," Ryan added.
Interestingly, the team also found that women who were currently pregnant had cells that looked younger than predicted.
"Paradoxically, even though a woman's biological age was higher with each child that she had, if a woman was pregnant when the measurements were taken, her epigenetic age, and to a lesser extent her telomeres, looked 'younger' than predicted for her chronological age," Kuzawa said.
"It's an interesting situation in which pregnancy makes someone look temporarily 'young,' but there appears to be some lasting, cumulative relationship between the number of pregnancies and more accelerated biological age," Kuzawa noted.