They were less likely to suffer domestic violence, substance abuse, depression than other moms-to-be.

(HealthDay)—Compared with unmarried women, married women are less likely to experience domestic abuse, substance abuse or postpartum depression around the time of pregnancy, a new study finds.

Researchers looked at data from more than 6,400 women who took part in the 2006-2007 Canadian Maternity Experiences Survey, and found that about 10 percent of married women experienced at least one of the problems.

In contrast, the rates were 20 percent for women who lived with a partner but were not married, 35 percent for single women who had never married, and 67 percent for women who became separated or divorced in the year before they gave birth, the investigators found.

The study authors also noted that the longer a woman cohabitated with a partner, the less likely she was to experience these types of problems.

It's not clear whether problems such as partner abuse or substance abuse were the cause or result of separations and divorces, study author Dr. Marcelo Urquia, an at the Centre for Research on Inner City Health at St. Michael's Hospital in Toronto, pointed out in a hospital news release.

The study was published in the December issue of the .

It is important to know what the differences are between married couples and those who live together as the number of children born outside marriage rises, Urquia said. He noted that 30 percent of children in Canada are born to unmarried couples, up from 9 percent in 1971. Births to outnumber those to in several European countries, according to background information in the news release.

More information: The U.S. Office on Women's Health has more about domestic and intimate partner violence.

Journal information: American Journal of Public Health