A study by the University of Oslo in Norway compared a group of 40 women who suffered a miscarriage with 80 women who chose to have an abortion for up to five years after the event.
After 10 days, 47.5 per cent of women who had miscarried suffered some mental distress compared with 30 per cent of the abortion group. But the miscarriage sufferers' distress decreased to just 2.6 per cent by two years and five years. However, 20 per cent of the abortion group were still experiencing distress after five years.
The team said both sets of women should be given help about the psychological effects of losing a baby.
Anna Pringle, from the anti-abortion group Life, said: "The emotional suffering [after having an abortion] can be massive."
But the Family Planning Association said: "There is no evidence to suggest abortion directly causes psychological trauma."