Britney Spears announced she's expecting a baby on Instagram this week and also revealed that she had perinatal depression when she was pregnant previously.

"I have to say it is absolutely horrible," Spears wrote. "Women didn't talk about it back then." 

Perinatal depression is a mood disorder that can start during pregnancy or after childbirth, while postpartum depression specifically describes depression someone develops after giving birth. While the direct causes of the disorders vary, the anxiety, sadness, apathy and other emotions many new or soon-to-be parents feel can be difficult to describe to loved ones or bring up at a doctor's appointment. 

Despite this, it's a common medical experience during pregnancy or the postpartum period. According to the American College of Obstetricians and Gynecologists, one in seven women will experience perinatal depression. 

Julianne Zweifel is a clinical psychologist and adjunct professor at UW Health in Madison, Wisconsin who works with people who have postpartum mood dysregulation, which can vary from postpartum "baby blues" to postpartum depression. In a September interview with CNET, she said the pressure to feel a certain way can lead new parents to feel inadequate when they don't feel what they perceive to be the "right" feelings.

"I like to describe it as [being] analogous to having only seen black-and-white photos all your life, and suddenly [you] see color photos," Zweifel said about new parents' expectations. "Like, 'wow, I didn't even recognize this dimension existed.'" 

The hormonal surges and lifestyle changes pregnancy and new parenthood bring can have dramatic effects on someone's mental health. If you're feeling society's expectation of how pregnant people and new parents should feel doesn't reflect your experience, here's what to know about perinatal and postpartum depression.

Depression during pregnancy 

During pregnancy, your body goes through huge changes as it accommodates a new body and prepares for the marathon of childbirth (and parenthood). On top of the physical and hormonal changes, pregnancy can put strain on relationships and cause financial stress. But like depression in people who aren't pregnant, it may also have genetic causes. 

According to the Cleveland Clinic, you're more at risk of experiencing depression during your pregnancy if: 

• You have a history of depression or premenstrual dysphoric disorder (PMDD, or severe PMS that disrupts daily life).
• You became pregnant at a younger age (risk decreases as age increases). 
• You live alone or have limited social support.
• You're experiencing marital problems.
• You have mixed feelings about your pregnancy.

The pandemic may also have increased the rate of anxiety or depression during pregnancy.

While depression can strike at any time in life, many people experience anxiety or depression for the first time while they're pregnant. Because depression can affect the health of the pregnant person and growing fetus, it's important to see your doctor or a mental health professional if you're experiencing symptoms of depression for at least two weeks, the ACOG says. Symptoms include, but aren't limited to: 

• Depressed mood most of the day, for most days. 
• Feeling guilty, hopeless or worthless. 
• Loss of interest in work or activities. 
• Sleep problems (sleeping too much or having problems going to sleep).
• Big changes in appetite (losing appetite, or eating much more than normal).
• Having trouble concentrating or making decisions. 
• Thinking about death or suicide.

Treatment for depression during pregnancy may be similar to treatment for people who aren't pregnant, including talk therapy or medication, according to the ACOG. 

Resources and an expert hotline to call for people experiencing depression during pregnancy and the postpartum period can be found at Postpartum Support International. An analysis of anxiety and depression in pregnant people during the pandemic found that increased social support and physical activity reduced the likelihood of developing either disorder during pregnancy.

Postpartum blues vs. postpartum depression

Zweifel said as many as 65% to 70% of people will experience postpartum "baby blues," or mood swings that begin roughly within a week of delivery. "Once you start using numbers like that, that means that's the normal response," she said. But baby blues will resolve on its own, usually getting better in about seven to 10 days. If feelings of classic depression persist without showing signs of getting better after about two weeks, Zweifel said, it's likely postpartum depression.

Symptoms of postpartum depression can be more intense and last longer than baby blues, and can potentially interfere with your ability to care for your baby or handle daily tasks, according to the Mayo Clinic. PPD can manifest differently and may include typical symptoms of depression, such as severe mood swings, feelings of worthlessness and a withdrawal from family and friends, but may also include feelings specific to your role as a parent, including feelings that you're not a good parent or thoughts and fears that you'll harm your child, per the Clinic. 

Zweifel wants to clear up the misconceptions about PPD and the idea that it makes people harm their child. 

"Somehow, our society has assumed that's a part of the scenario, and I feel like that's part of the problem," she said. There is a big difference, she said, between fearing that you'll "lose control" and hurt your child, or having intrusive thoughts of you dropping them, than of actually harming your child. "The intent is different there," Zweifel said. 

Postpartum psychosis is a very rare condition which can result in the afflicted person attempting to harm themselves or their baby. According to the Mayo Clinic, some of the signs of postpartum psychosis include confusion, paranoia, excessive energy and agitation, hallucinations and delusions. 

Read more: 13 Suicide and Crisis Intervention Hotlines to Call or Text When You Need Help

Postpartum depression causes

Many factors can contribute to depression after childbirth, including social factors like not having a support system, societal pressure to feel a certain way and the way a person's body reacts to hormonal changes.

Hormones

Estrogen and progesterone levels skyrocket during pregnancy and then very quickly after birth, they start to drop. This huge dip in hormones is what causes many people to experience strong emotions following birth. 

Research suggests that there's not different hormone levels or amounts in people who experience PPD compared to people who don't, Zweifel said. But there might be a difference in how their brain responds to changes in estrogen. Zweifel called the varying chemical effect of estrogen as a "prominent working theory," but it helps explain why oftentimes the people who experience severe mood changes in connection with their menstrual cycle may also be more likely to experience PPD or have more mood-related symptoms during menopause. 

"That subset is experiencing the same changes and same patterns," Zweifel said. "But the receptor sites in their brain, essentially, sort of respond differently. They're extra sensitive."

Outside factors

Zweifel said a lot of people experiencing symptoms of depression who come into her office feel better almost immediately after she dispels myths about what makes someone an inferior parent -- missing the "golden hour" of contact with a newborn for medical reasons, for example, or choosing to formula feed instead of breastfeed. Another record she has to set straight is the idea that all parents have an immediate bond with their infant, and if they don't, it means there's something wrong with them. 

"Bonding with an infant takes time, and our society does a terrible job of being honest with women about this," Zweifel said. She likes to instill the idea of a "fourth trimester," because there's still so much developing happening on the baby's end in the first few weeks of life that makes the parent-child relationship very straining on the parent, often leaving them "starved for validation" because the baby isn't able to acknowledge the parent, or even able to focus their eyes yet. 

In addition to unrealistic expectations of what it means to be a parent, Zweifel said other factors like being the only parent who gets up when the baby cries can exacerbate PPD, or having a child with acid reflux or other medical conditions that require extra care. 

Other risk factors, per the CDC, include being a parent to multiples (twins, triplets or more), being a teen parent, having a family or personal history of depression, having a preterm or complicated birth, experiencing difficulty getting pregnant and other stressful events surrounding pregnancy. 

PPD is also not a limited experience to the person giving birth. Although the other parent won't be experiencing the hormonal changes that can cause symptoms of depression, similar lifestyle changes, added stress, lack of sleep and societal pressure remain. A 2014 study published in the journal Pediatrics found that depression among new dads increased an average of 68% the first year of their child's life.

If your mental health is a concern to you, reach out for help. If you're interested in seeking treatment with medicine, Zweifel recommends finding a psychiatrist or another professional who works specifically with people on postpartum mood dysregulation.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.