Nurses and midwives should be fully aware of women's childbirth history, a study has shown.
Research published in BJOG: An International Journal of Obstetrics and Gynaecology, found women are 50 times more likely to suffer a life-threatening ruptured womb during labour if they have previously had a Caesarean delivery.
Ruptures developed in nine out of 1,000 mothers giving birth to their second baby naturally after having their first child by Caesarean.
The complication was found in fewer than two in every 1,000 women who had given birth to their first child vaginally.
Older mothers were found to be more at risk, with those who gave birth aged 35 or older nearly three times as likely to suffer a torn womb than those aged 24 or younger.
Women giving birth to babies of 4kg or more were also twice as likely to suffer a torn womb than those with infants under 4kg.
Melissa Kaczmarczyk, from the Department of Epidemiology at Emory University, said: "We found that previous caesarean, induction of labour and high maternal age significantly increase the risk of uterine rupture.
"This is of particular concern due to a rise in the presence of these factors within the pregnant population."