One of the largest studies to look at the effect of induced abortions has found that women who have had three or more abortions have a higher risk of delivering a baby who is born prematurely and with a low birth weight.
The research, which is published in the medical journal Human Reproduction, found that among 300,858 Finnish mothers, 31,083 had had one induced abortion between 1996-2008, 4,417 had two, and 942 had three or more abortions before a first birth.
Those who had had three or more induced abortions had a small, but statistically significant increased risk of having a baby with very low birth weight (less than 1500g), low birth weight (less than 2500g), or of a preterm birth (before 37 weeks), or very preterm birth (before 28 weeks) — compared to women who had had no abortions. There was a slightly increased risk of a very preterm birth for women who had had two induced abortions.
Women shouldn’t be alarmed
“Our results suggest that induced abortions before the first birth, particularly three or more abortions, are associated with a marginally increased risk during the first birth. However, the increased risk is very small, particularly after only one or even two abortions, and women should not be alarmed by our findings, “said Dr Reija Klemetti, an associate professor and senior researcher in public health at the National Institute for Health and Welfare in Helsinki, Finland, who led the research.
At least 88% of the abortions were surgically performed and 91% were performed before 12 weeks gestation. The researchers adjusted their findings to take into account the various factors that could affect birth outcomes, such as social background, marital status, age, smoking, previous ectopic pregnancies and miscarriages. The risk of having a baby born very preterm appeared to increase slightly with each induced abortion, but only the risk from two abortions or more was statistically significant.
“To put these risks into perspective, for every 1000 women, three who have had no abortion will have a baby born under 28 weeks,” said Dr Klemetti. “This rises to four women among those who have had one abortion, six women who have had two abortions, and 11 women who have had three or more.”
Among women who had had three or more abortions, there was an increased risk of 35% of having a baby born preterm (before 37 weeks), and a 225% increased risk of very low birth weight, and a two-fifths (43%) increased risk of low birth weight.
More findings, but numbers low
The study also indicated a small increased risk of a baby’s death around the time of birth. However, the numbers were very low and should therefore be treated with caution. In addition, the authors say they might not have been able to fully adjust for all the factors that could affect this result and perinatal deaths are sensitive to social factors such as poverty.
“Our study is the first large study to look at a broad set of perinatal outcomes and to control, at least partly, for the most important confounding factors such as smoking and socioeconomic position,” said Dr Klemetti. “However, it is important to say that even though we adjusted for these factors, and also ectopic pregnancies and miscarriages, there might be some confounding for social class that we could not control for. Most probably, this may be related to women’s (or some of these women’s) way of life, life habits, and sexual and reproductive health.”
“Furthermore, this is an observational study and, however large and well-controlled, it only shows there is a link between abortion and some adverse birth outcomes — it cannot prove that abortions are the cause.
“We suggest that the potential for increased risks for subsequent births should be included in sex education, especially as there are other, good reasons to avoid induced abortions. Health professionals should also be informed about the potential risks of repeat abortions.”