For five years, researchers tracked nearly 1,000 women who either received or were denied abortions from 30 facilities in 21 U.S. states.

Altogether, 273 women received an abortion in their first trimester, 413 received an abortion within two weeks of the facility's gestational limit, and 231 were denied an abortion because their pregnancy fell within the three weeks after the facility's limit.

A week later, compared to women who received abortions, those who were turned away were more likely to report anxiety symptoms, lower self-esteem and lower life satisfaction.

"Those differences disappear after six months to a year," said lead author Antonia Biggs of the University of California, San Francisco. By six months, women who had abortions and those who were turned away had similar mental health profiles.

Nine states have laws that force healthcare providers to tell women that having an abortion will increase their risk for mental health problems, Biggs and her colleagues point out in JAMA Psychiatry, online December 14th.

"This research shows the information they are mandating women receive (is)inaccurate and out of date," Biggs told Reuters Health. "We don’t have evidence that abortion leads women to have worse mental health."

"It’s true that we haven’t had great evidence looking at this particular question before," she said. "Now that we do, we should really go back and think about the information we’re giving women and making sure it’s accurate and up-to-date."

Biggs and colleagues write that numerous studies of the mental health effects of abortion on women found no evidence that it leads to poor outcomes, but those studies were often flawed. This new study, Biggs said, addressed limitations in past research. Women seeking abortions were compared to other women seeking abortions, and not women who wanted their pregnancy. Additionally, the comparisons were made among women who were around the same point in their pregnancies.

In a statement, the chief medical officer of Planned Parenthood Federation of America said the results show why politicians should not play doctor.

"Every woman should have accurate information about all of her options," said Raegan McDonald-Mosley in the statement. "That information should support a woman, help her make a decision for herself, and enable her to take care of her health and well-being. It should not be provided with the intent of coercing, shaming, or judging a woman."

The researchers caution that the new study can't say denying women abortions caused the increase in symptoms. Additionally, only 40 percent of invited women agreed to participate in the study, and nearly a third of participants did not complete all five years of follow-up.