MONDAY, Feb. 6 (HealthDay News) -- Women with a history of mental illness do not seem to be at increased risk of readmission to a psychiatric hospital after having an abortion in their first trimester, a new study suggests.

The findings, which appear in the February issue of the Archives of General Psychiatry, support several previous studies showing that women who undergo abortion do not face a higher risk of mental health problems afterwards.

But anti-abortion advocates say the psychological risks of abortion are still not fully understood.

"The take-home message from our study is that having a first-time, first-trimester induced abortion does not influence readmission risk, since risk of readmission is similar before and after the abortion procedure," said study author Dr. Trine Munk-Olsen, an epidemiologist at Aarhus University in Denmark.

Women in this latest study were considered at risk because they had a record of at least one previous admission to an inpatient psychiatric facility. "We speculate that having mental health problems influences women's decision to have an induced abortion, but this decision did not appear to influence the illness course in this group of women," Monk-Olsen said.

Rachel Jones is a senior research associate at the Guttmacher Institute in New York City, which says it works to advance sexual and reproductive health and rights. "This is one more piece of good-quality research showing that there isn't an increased risk of serious mental health problems after abortion. The findings should provide further reassurance that abortion does not cause significant mental health problems," she said.

The researchers used registry information of all women born in Denmark between 1962 and 1992 who had a record of one or more psychiatric admissions at least nine months before either a first-time abortion during the first trimester or childbirth. There were 2,838 women with records of mental disorders who underwent a first-trimester abortion between January 1994 and December 2007.

During the period from nine months before to 12 months after the abortion, 321 women were readmitted to a psychiatric hospital. By contrast, 5,293 women with records of mental disorders gave birth to their first child during the same study period. Among these women, 273 were readmitted from nine months prior to 12 months after childbirth, the study showed.

Although rates of readmission were higher overall among women having abortions, readmission rates were higher a month afterwards in the group of women who decided to go through childbirth, the study authors said.

Risk factors for readmission included a parental history of mental disorders. Risk was also highest among women in both groups who had been hospitalized closer to the time of their pregnancy, abortion or birth. The risk of readmission was reduced in women with one or more children at the time of abortion, according to the study.

Priscilla Coleman, a professor of human development and family studies at Bowling Green State University in Ohio, took issue with the new findings.

She noted that the study was funded by the Susan Thompson Buffett Foundation, which, Coleman said, supports research on abortion rights. And the women in the study were only followed for one year after their abortion or the birth of their child, but women may experience emotional upheaval from the experience years later, she said.

"The design is so problematic that the results really don't mean a lot," Coleman said. "There is a wealth of data in the literature building a strong case that abortion could be detrimental to a certain proportion of women. We need to be helping women and not telling them, 'It is no big deal.'"

Jeanne Monahan, director of the Center for Human Dignity at the Family Research Council, an anti-abortion group based in Washington, D.C., said, "The [study] findings can't be 100 percent trusted.

"I think of the women that I know in my own life, and many of the stories I hear from women who suffer from post-abortion syndrome and really profoundly regret their abortion," she said.

More information

Learn more about mental illness at the National Alliance on Mental Illness.