In recent years, mental health struggles have become the leading cause of maternal mortality in the United States, primarily as a result of suicides and drug overdoses. It is estimated that one in eight new moms experience postpartum depression, and some research has suggested that the prevalence climbed to as high as one in three during the early days of the pandemic.

Yet roughly half of the women who are struggling with their mental health after pregnancy don’t receive treatment. Barriers to care include a lack of awareness about symptoms and treatments, an inability to access resources and stigma.

Postpartum depression has historically been underdiagnosed and under-researched, but recognition of the condition is finally growing. As a result, there are more treatment options available than ever before, including innovative therapeutic models and at least one new medication.

Many women experience mood swings in the days and weeks following birth because of the dramatic hormonal shifts that occur. Sometimes called the “baby blues,” symptoms include feelings of sadness, anxiety, tearfulness or overwhelm; they typically subside within a week or two.

New mothers “feel like they’re on a hormonal ride because they are,” said Dr. Samantha Meltzer-Brody, the chair of the psychiatry department at the University of North Carolina at Chapel Hill, who helped found the university’s perinatal psychiatry inpatient unit — the first in the country. “That happens to every single person that gives birth, and that’s considered a normal part of the transition from pregnancy to the postpartum period.”

Postpartum depression is different. It is defined as a major depressive episode that lasts at least two weeks and starts during the year after birth, usually emerging in the first few weeks.

“To meet criteria for a postpartum depressive episode, you must meet criteria for a major depressive episode,” Dr. Meltzer-Brody said. Those include persistent low mood, low energy, feelings of worthlessness or guilt, suicidal thoughts and a loss of interest in things that were previously enjoyable.

The condition is typically screened for using a questionnaire known as the Edinburgh Postnatal Depression Scale, which is ideally (but not always) administered at the six-week postpartum visit to the obstetrician’s office. Pediatricians are also encouraged to ask about postpartum depression because they see the family more frequently in the year after birth. Risk factors include a history of depression, a traumatic birth experience and lack of social support, said Dr. Latoya Frolov, a perinatal psychiatrist at the University of Texas Southwestern Medical Center.

Postpartum depression can affect not only the mother’s health but also that of her baby. Some research has shown that infants born to depressed mothers gain less weight and have more illnesses and developmental delays (though some other studies have not). As a result, timely treatment is important.

The treatment a woman receives should depend on her score on the Edinburgh Scale, but all too often there is no follow-up care, either because adequate mental health resources aren’t available or because she can’t access them.

It’s hard to make it to an appointment when you’re overwhelmed, exhausted and depressed, especially if you don’t have easy transportation or child care, Dr. Frolov said. “When I see someone make it to an appointment with me, I am overjoyed, honestly, to see them in my office, because I know that often there’s a lot that went into it.”

If a woman is found to have mild to moderate depression, she should quickly be referred to some sort of therapy.

Group therapy is often recommended for new moms who are struggling, and it can be one of the most powerful interventions, said Paige Bellenbaum, a licensed clinical social worker and the founding director of The Motherhood Center, a clinic in New York City that offers intensive outpatient care for women with postpartum depression. “It’s the support that women provide to one another,” she said, “that helps them to feel so much less alone in this really, really challenging journey.”

In one-on-one therapy, counselors often use approaches like cognitive behavioral therapy, dialectical behavioral therapy and interpersonal therapy, which provide women with skills to help them manage their emotions, avoid or reframe negative thoughts and improve communication with their partner.

For women who have moderate to severe postpartum depression, experts often recommend medication — most commonly selective serotonin reuptake inhibitors, or S.S.R.I.s. There is limited research specifically testing S.S.R.I.s for postpartum depression, but one meta-analysis assessing six studies indicated that a little less than half of the women who take them see an improvement.

Traditionally, doctors have worried that these medications are unsafe for women who are pregnant or breastfeeding, but Dr. Frolov said the risks are small, especially compared to those associated with postpartum depression. She said Zoloft, in particular, is frequently prescribed because less medication is secreted into breast milk than with other S.S.R.I.s.

Dr. Frolov is trying to empower physicians who work with pregnant and postpartum women to feel more comfortable prescribing S.S.R.I.s, especially to women who are struggling but aren’t able to see a mental health professional. “I always encourage OBs to treat,” she said. “It’s not enough to screen.”

For women who don’t respond to these therapies, more intensive treatment options are starting to become available, including full-day outpatient and inpatient facilities dedicated to maternal mental health, like The Motherhood Center and U.N.C.’s perinatal psychiatry unit.

Two medications specifically approved for postpartum depression also now exist, and they work differently from S.S.R.I.s. The first, called brexanolone, which was approved by the Food and Drug Administration in 2019, causes a significant reduction in depression scores for about 70 percent of the women who receive it, said Dr. Meltzer-Brody, who ran the clinical trials at U.N.C. Most notably, it works within 24 hours, compared with the weeks or months it takes to see a benefit from therapy or S.S.R.I.s.

While brexanolone’s efficacy is promising, it must be delivered in a hospital via an I.V. for 60 hours straight, which makes it extremely difficult to access. As a result, only a few hundred women, usually the most severe cases, have been treated with the drug since it became available.

Experts are more excited about a related fast-acting medication that can be delivered in pill form and taken for two weeks, Dr. Frolov said. The drug, called zuranolone, was approved by the F.D.A. in August for postpartum depression.

Zuranolone appears to be slightly less efficacious than brexanolone, but it’s a lot easier to take and so should be accessible to more new moms. In a recent clinical trial, 57 percent of patients had a significant reduction in their depression symptoms after two weeks on the medication, compared with 39 percent of those who received a placebo. Women in the study started improving as early as their third day taking the drug, and the benefits lasted for at least 45 days. The researchers didn’t follow the women past 45 days, so they don’t know how long the benefits last, but if someone relapses they could be treated again.

Perhaps even more important than the new medications themselves, Ms. Bellenbaum said, is the fact that the medical and scientific community is investing in research into postpartum depression. “The field of maternal mental health is finally starting to matter,” she said.