Women may develop ruptures in their womb while giving birth to babies naturally if they have previously had a caesarean section delivery, Swedish researchers said.
The scientists called for extra care to be given to women with a history of caesarean delivery and said doctors should ensure they were fully aware of their childbirth options.
The chemical used to induce birth weakens previous caesarean scars, making them more likely to rip and women who gave birth late could be 50 times more vulnerable to the damage than those who gave birth after a normal-length pregnancy, the researchers said.
Scientists studied more than 300,000 Swedish women and found the condition struck nine in every 1,000 mothers who attempted to give birth to their second baby naturally after having their first child by a caesarean section, reported the online edition of the Daily Mail.
But the complication was found in fewer than two of every 1,000 who had given birth to their first baby naturally. The study was published in the British Journal of Obstetrics and Gynaecology.
If the uterus tears, it is life threatening for both the mother and baby. Around one in 20 babies die, the scientists said.
A prior caesarean section was not the only factor that increased the risk of the womb being ruptured. Women who gave birth when they are aged 35 or older were nearly three times more vulnerable to a uterine rupture than women aged 24 or younger, said another report appearing in the online edition of BBC News.
Clinically obese women had more than twice the risk of women who were not overweight. And inducing labour appeared to double the risk as compared to labour which began spontaneously.