A single termination raised the risk by 20%. Two or more increased the chances by 90%.

And women who have had more than one abortion double their risk of having a "very" premature baby - classed as being born before 34 weeks.

Lead researcher Dr Robbert van Oppenraaij said: "It can be concluded that a history of abortion is associated with an increased risk for premature delivery and very premature delivery."

He added more research was needed as the findings showed only an association between abortions and pre-term delivery and not necessarily a direct link.

The study also looked at miscarriages, finding that having more than one almost doubled the likelihood of congen-ital malformations in the baby. It also nearly doubled the risk of pre-term rupture of the membrane that surrounds the baby in the womb. This is known to raise the chances of an early birth.

The findings are to be presented today at the annual European Society of Human Reproduction and Embryology in Amsterdam.