WEDNESDAY, Jan. 26 (HealthDay News) -- Women who undergo an abortion don't seem to face a greatly increased risk of mental health problems after having the procedure, a new study suggests.

Trine Munk-Olsen, lead author of the study published in the Jan. 27 issue of the New England Journal of Medicine, said she was "not surprised by [the] findings," given that they mirror previous research on the subject.

"Most well-made studies in the field of abortion and mental health show that having an abortion is not associated with an increased risk of having a psychiatric episode," she said.

A small study published in the December issue of the journal Perspectives on Sexual and Reproductive Health reported similar findings: Teenagers who have an abortion aren't more likely to be depressed or have low self-esteem than other pregnant teens. But Priscilla K. Coleman, a professor of human development and family studies at Bowling Green State University in Ohio, who believes having an abortion boosts the risk of mental health problems, said at the time that the study was too small to reach reliable conclusions because it looked at just 69 teens who had had abortions.

On the latest research, Dr. Joe DeCook, director of operations for the American Association of Pro Life Obstetricians and Gynecologists, said, "this Danish study must be balanced by a comparison to the large number of studies that conclude that there is indeed, for many women, a serious and long-lasting untoward result on their mental health wholeness... Fifty percent of abortions are repeat abortions, and the Danish study does not comment on this half of the affected population. Additionally, 11 percent of abortions happen after the first trimester, and these women are likewise not included in this analysis.These are women generally felt to be at higher risk for subsequent mental health problems."

Some previous studies had found that abortion might negatively affect mental health, and the authors of the Danish study noted that it's not inconceivable that an unwanted pregnancy could itself cause mental health problems. So, the authors said they set out to study the issue in a methodical way.

"We followed all women having abortions in Denmark from 1995 through 2007. Each woman having a first-time, first-trimester-induced abortion was followed individually from nine months before the procedure to 12 months after," said Munk-Olsen, a postdoctoral fellow at the National Center for Register-Based Research at Aarhus University in Aarhus, Denmark.

"During this period, we studied if the women had been admitted to a psychiatric hospital or had records of treatment at an outpatient clinic," she added.

In Denmark, abortions are both free and legal during the first trimester.

"Fifteen out of 1,000 women had a first-time psychiatric episode during the first year after having a first-trimester-induced abortion," Munk-Olsen said.

The most frequent reasons for psychiatric visits were neurotic or stress-related complaints. Some past studies may have included issues such as sadness or regret, which don't necessary constitute a mental disorder, Munk-Olsen said.

Among women and girls who actually delivered a baby, about four in 1,000 had a first-time psychiatric episode before the baby and about seven afterward -- an increase possibly related to postpartum depression, the study authors said.

"The higher level of psychiatric contacts in the abortion group could reflect that the women are at a vulnerable time in their lives, but we do not know this," Munk-Olsen said.

Dr. Vanessa Cullins, vice president for medical affairs at Planned Parenthood Federation of America, said, "The findings show that motherhood and parenting are decisions with lifelong implications and that individual women are in the best positions to decide when and if they are ready to give birth."

More information

The U.S. National Library of Medicine has more on abortion.