One in six women experience at least a mild form of depression during pregnancy, according to research published in Archives of Women’s Health. One in seven experience depression after they give birth, known as postpartum depression, according to the American Psychological Association (APA). Depression both during and after pregnancy is known as perinatal depression. Depression is a mood disorder marked by major changes in emotional experience — including sadness, loss of interest, and hopelessness — that cause considerable distress and may interfere with daily life for a prolonged period. There are multiple types of depression, including:

Major depressive disorder, also known as major depression or clinical depression (severe depressive symptoms that last for at least two weeks)Persistent depressive disorder (low-level depressive symptoms that last for at least two years)Seasonal affective disorder (depression that most often happens during winter or fall due to lack of sunlight)

Although a lot of attention has been paid to postpartum depression, public health experts are focusing more and more on the high incidence of antepartum depression — debunking the myth that pregnancy is always a blissful period in a woman’s life. The mismatch between cultural expectations and personal experience can make it even more difficult for pregnant women to cope with depression and seek help, according to APA experts. For example, there can be an expectation that a woman who is pregnant will feel joyful and content, but many women struggle with difficult emotions during pregnancy. As a key step in addressing this problem, the U.S. Preventive Services Task Force (USPSTF) recommends that both pregnant women and new mothers be screened for depression. On the other hand, many women have their first experience of depression while they’re pregnant. Depression during pregnancy is generally thought to be caused by a combination of hormonal changes and psychological changes associated with pregnancy, say experts at the National Institute of Mental Health. Other changes during pregnancy, such as bodily changes and alterations in sleep and eating habits, can contribute to antepartum depression. In addition to a history of depression, ACOG experts say, other risk factors for depression during pregnancy include:

StressHistory of anxietyA pregnancy that wasn’t intendedInsufficient social support systemDomestic violenceHaving Medicaid insuranceLower income or education levelSmokingBeing in an unhealthy relationshipBeing a single mother

Persistent feelings of sadness or emptinessLoss of interest in activities or hobbies once enjoyedFeeling hopeless, worthless, helpless, or guiltyFrequently feeling irritated, anxious, frustrated, or angry

It’s important to note that a number of symptoms of major depression are similar to the changes that many pregnant women typically experience:

Fatigue and decreased energySleep disturbancesChanges in appetite and eating habits

This overlap can make it very difficult for healthcare providers to identify pregnant women who need professional mental health care. Women with antepartum depression are also at higher risk for postpartum depression. Untreated depression during pregnancy poses a health risk to the pregnant woman as well as the infant by increasing the risk of:

Complications with pregnancy or deliveryDelivering a low-birth-weight babyPrematurely giving birth

In a study of more than 7,000 pregnant women, published in the May 2016 issue of Obstetrics & Gynecology, the odds of having a premature baby were 1.82 times higher in those with antepartum depression than those without it, and the odds of having a baby with a low birth weight was 1.28 times higher in those with antepartum depression than those without it.

Counseling or therapy, including specific techniques such as cognitive behavioral therapy (CBT) and interpersonal psychotherapy, guided by a mental health professionalSupport groupsMedications

Prescription antidepressants offer benefits to both the mother and her child that need to be balanced carefully against the risks. Although research findings have been mixed, the USPSTF review of the scientific evidence suggests that antidepressant use during pregnancy was associated with a small increase in the risk of serious harm to infants. Pregnant women should discuss the pros and cons of treatment with a particular antidepressant medication with their doctors. While some pregnant women experience such severe depression that antidepressants are essential, for women with milder forms of depression, counseling or therapy can be an effective option. In reviewing studies of nondrug treatments, the USPSTF found that CBT — which aims to help people uncover unhelpful patterns of thought and replace those patterns with more useful and accurate ones, as well as making behavioral changes that are known to boost mood — had the strongest evidence of effectiveness in pregnant and postpartum women with depression. Interpersonal psychotherapy — which focuses on exploring a person’s relationships, identifying problems in those relationships, and improving interpersonal skills — can also be effective in treating depression. Brain stimulation therapies, such as electroconvulsive therapy (ECT), in which a low-level electrical current is passed through the brain, may also treat antepartum depression — though a review of case studies published in the Archives of Women’s Mental Health recommended using ECT only as a last resort. Lifestyle changes such as a balanced diet, regular exercise, and enough sleep each night can also help women struggling with depression, according to the APA. Researchers are devoting more time to finding out whether mindfulness practices, such as meditation and yoga, can treat depression during pregnancy. One pilot study, published in 2016 in the Journal of Consulting and Clinical Psychology, found that mindfulness-based cognitive therapy prevented relapses in pregnant women who had experienced depression in the past. The American Pregnancy Association offers educational materials on depression during pregnancy, as well as phone counseling about pregnancy and reproductive health. Dial 800-672-2296 to reach the toll-free help line. “A Day With: Antenatal Depression” Headspace, a virtual mental health platform, offers an ongoing series of personal essays, “A Day With,” about what it’s like to live with different mental health conditions. “A Day With: Antenatal Depression” addresses one person’s personal experiences with this condition. RELATED: 8 Depression Symptoms You Shouldn’t Ignore Additional reporting by Pamela Kaufman.