A new study by researchers at the University of Maryland School of Public Health finds that the more maternity leave time a woman takes after giving birth the less likely she will be to suffer from postpartum depression.

“In the U.S., most working women are back to work soon after giving birth, with the majority not taking more than three months of leave,” says Rada K. Dagher, Ph.D., an assistant professor of health services administration at the University of Maryland School of Public Health. “But,” says Dagher, “our study showed that women who return to work sooner than six months after childbirth experience increased postpartum depressive symptoms.”

The study authors used data collected from the Maternal Postpartum Health Study, based at the University of Minnesota School of Public Health. The data showed that at the six weeks, twelve weeks, and six months time frames, women on maternity leave had significantly lower postpartum depression scores than those who had returned to work.

The study authors noted in the study that 2013 marks the twentieth anniversary of the passage of the Family and Medical Leave Act (FMLA), a federal policy which provides a maximum of 12 weeks of unpaid leave for eligible employees (who typically work for firms with fifty or more employees) but since many women are not covered by the law, or cannot afford to take unpaid leave, most come back to work much sooner than may be best for avoiding postpartum depression.

The study found that in the data set they used, about 7 percent of the mothers were back at work by 6 weeks, 46 percent by 12 weeks, and 87 percent by 6 months. The researchers say that the U.S. lags well behind all other industrialized nations in how much parental leave is offered.

The researchers conclude their study by saying that “the current leave duration provided by the Family and Medical Leave Act, 12 weeks, may not be sufficient for mothers at risk for or experiencing postpartum depression” and recommends that future discussions on the issue of parental leave take postpartum health of mothers into account. The researchers recommend that employers consider offering more than 12 weeks of leave.

The study was published in the Journal of Health Politics, Policy and Law.