Women who end their first pregnancy with an abortion increase the chances of giving birth prematurely second time around, say researchers.
The risk is higher for surgical than for drug-induced abortions, a large study found.
Previous research has associated multiple terminations with a range of complications for future pregnancies including pre-term birth.
But only a very small percentage of women have two or more induced abortions before attempting to have a baby.
The new study suggests that the much greater proportion of women who have undergone just one abortion after their first experience of pregnancy may also be at risk.
Overall, their chances of a next pregnancy leading to premature birth was 37% higher than it was for women who had never been pregnant before.
However, the risk was slightly lower than it was for women whose first pregnancy ended in a miscarriage.
Premature birth before the 37th week of pregnancy is linked to a range of health problems for babies. These can include lung disease, cerebral palsy, jaundice, infections, anaemia and mental problems later in life.
The scientists based their findings on pregnancy outcome data on more than 620,000 women in Scotland, recorded between 1981 and 2007.
Study leader Professor Siladitya Bhattacharya, from the University of Aberdeen, said: “Many women start their reproductive life with an abortion in their first pregnancy.
“Abortion is common; most people know somebody who has undergone an abortion. The statistics for Scotland are compelling. In the last five years, 12 to 13,000 women have had abortions every year, and 40% of those are women under the age of 25.
“We found that women who had a previous induced abortion had a higher risk of spontaneous pre-term birth in their next on-going pregnancy, compared to women who had never been pregnant before.”
Women with a history of three or four abortions were not significantly more at risk of delivering a baby prematurely than those who underwent just one abortion, the study showed.
The findings were presented today at the British Science Festival being held at the University of Aberdeen, and reported in the online medical journal BMJ Open.