A second study shows that women who lose a baby by the age of 21 either through an abortion or a miscarriage are three times more likely to develop a drug or alcohol problem than others.
Researcher Kaeleen Dingle, of the University of Queensland, Australia, said: Abortion and miscarriage are stressful life events that have been shown to lead to anxiety, sadness and grief and, for some women, serious depression and substance use disorders.
The Royal College of Psychiatrists called the evidence inconclusive.
But pro-life campaigners claim it shows women should be warned of all the risks of abortion.