A new set of guidelines released today by the United States Preventive Services Task Force (USPSTF) recommends, for the first time, depression screenings for pregnant women and women who have just given birth. The USPSTF, a volunteer panel of medical experts, last released depression-screening guidelines in 2009, but never mentioned pregnant or postpartum women, The New York Times reports.

The revamped guidelines follow recent findings that postpartum depression is more common than previously thought. In 2014, scientists found that depression often begins during pregnancy (rather than immediately after it) and can appear any time in the first year after a child is born, the Times reports. A 2012 study found that major depressive episodes went undiagnosed in 66 percent of pregnant women, and 59 percent in non-pregnant women.

Depression during pregnancy is more common than previously thought

"It’s very significant that the task force is now putting forth a recommendation that’s specific to pregnant and postpartum women," Katy Kozhimannil, an associate professor of public health at the University of Minnesota, told the Times. "Policy makers will pay attention to it. Increased screening and detection of depression is an enormous public health need."

The guidelines recommend depression screenings as part of a cohesive primary care plan for all people over 18 "regardless of risk factors," but specifies populations more prone to depression. Women (including pregnant women), young and middle-aged adults, and people of color statistically have higher rates of depression than others. Previous guidelines stated that physicians should screen patients if their practice had the resources to treat depression. Now the guidelines say doctors can diagnose patients and refer them somewhere else if the resources are unavailable.

Each year the USPSTF reports to Congress with suggestions for improving medical care and increasing research on "priority areas" in the medical field. Each recommendation receives a letter grade; the depression screening recommendation received a B, which means there is a high certainty of the benefit of the screenings. It also means depression screenings must be covered under the Affordable Care Act, according to the Times.

There is no "optimal interval" yet

New Jersey is currently the only US state that requires depression screenings for pregnant women. Last year, New York City mayor Bill de Blasio said screening for depression during pregnancy "should be a part of routine care" and launched an initiative to get all pregnant women and new mothers in the city screened.

The USPSTF says more research will have to be done until an "optimal interval" for depression screenings is decided.