A history of miscarriages and abortions increases a woman's chances of giving birth too early, research has shown.

The same study revealed that premature delivery was also more likely after any complication early in the pregnancy, or in previous pregnancies.

Researchers believe the findings will help doctors identify women who might need greater care and monitoring in the months leading up to the birth.

Scientists from Britain, Denmark and Spain analysed the results of 75 investigations into early pregnancy complications conducted between 1980 and 2008.

They found that a history of one or more miscarriages nearly doubled the risk of pre-term rupture of the membrane that surrounds the baby in the womb, thereby increasing the chances of a premature delivery.

Three or more recurrent miscarriages led to a six-fold increased risk of placenta praevia -- a condition caused by the placenta blocking the cervix -- and almost doubled the likelihood of congenital malformations in the baby.

If a pregnancy was terminated for any reason, this heightened the risk of premature and very premature delivery in subsequent pregnancies.

The findings were presented at the 25th annual meeting of the European Society of Human Reproduction and Embryology in Amsterdam.

Study leader Dr Robbert van Oppenraaij, from Erasmus MC University Medical Centre in Rotterdam, said: "While it is true that most conditions are difficult to prevent, with improved monitoring in high-risk pregnancies it is possible to reduce perinatal [around the time of birth] or postnatal [after birth] foetal complications."

The study found that problems encountered in the first three months (trimester) of pregnancy increased the risk of complications later in the same pregnancy.

For example, vaginal bleeding in the first trimester increased the risk of the high blood pressure condition pre-eclampsia and premature delivery, and more than doubled the risk of low birth weight.

Dr Oppenraaij said the finding of a six-fold increased risk of placenta praevia linked to recurrent miscarriages had to be treated with caution since it came from one small retrospective study.

- John von Radowitz