Your sister’s postpartum mental health could affect yours—here’s what new research reveals

When I had my second baby, I invited my sister, who at the time was living nearby—to attend the birth. My first labor and delivery had been such a shock, that I felt it was important to share the birth experience with her, so she’d be less in the dark if she one day had kids. She remains grateful for that precious experience we shared. 

Turns out, sisters share a lot.

If you’re pregnant or thinking about having a baby, you’ve probably heard of postpartum depression (PPD). But there’s another, rarer postpartum mental health condition that deserves more attention: postpartum psychosis. And according to a new study published in the American Journal of Psychiatry, your sibling’s experience with it could be more relevant to your own mental health than you might expect.

Researchers at Mount Sinai examined over 1.6 million women using Swedish national health records and uncovered a startling statistic: If your sister had postpartum psychosis, your own risk increases tenfold. That number rises to 14 times higher if she also has a diagnosis of bipolar disorder. You can read the study here: American Journal of Psychiatry and coverage from Neuroscience News.

Let’s pause here. That relative risk sounds terrifying—but what does it really mean?

While a tenfold increase sounds massive, it’s important to understand that the absolute risk of postpartum psychosis remains low: about 1.6%. That nuance matters. This is not about panic. it’s about being prepared.

“Every woman of childbearing age and their physicians need to know about the existence of, severity, symptoms, and familial risk for postpartum psychosis so it can be promptly diagnosed and, hopefully, prevented,” said Dr. Veerle Bergink, Director of the Women’s Mental Health Center at Mount Sinai and co-senior author of the study.

Here’s why this research matters for moms—and for sisters.

Related: I recovered from postpartum psychosis: Here are 5 things I learned

Postpartum psychosis: what to know

This isn’t the baby blues, and it’s not the same as PPD. Postpartum psychosis is a severe psychiatric emergency. It often appears within days to weeks after childbirth and can include:

• Hallucinations
  
• Delusions
  
• Paranoia
  
• Insomnia
  
• Rapid mood swings
  
• Disorganized thinking
  
• Suicidal thoughts or thoughts of harming the baby

These symptoms can be terrifying—and potentially life-threatening—if left untreated.

What to do if you have a family history

If your sister experienced postpartum psychosis, talk to your provider as early as possible in your pregnancy, or even before you conceive. You might benefit from closer monitoring, earlier mental health screenings, and a tailored postpartum support plan.

Preventive steps could include:

• Building a mental health care team before delivery
  
• Arranging postpartum support (think night doulas, therapist check-ins, or medication plans if appropriate)
  
• Involving partners, family, or close friends in awareness of early symptoms
  
• Avoiding sleep deprivation, a common trigger, through shared caregiving

Why this study empowers, not frightens

Knowledge is power—but only if we act on it.

Too often, maternal mental health risks fly under the radar, especially rare ones like postpartum psychosis. And when risks aren’t well known, moms suffer in silence. This study offers an opportunity to change that by building systems of support and awareness before a crisis hits.

As Dr. Bergink put it:

“Too many women at higher risk don’t know it—and are left on their own with a new baby and no support.”

And that’s a systemic failure—not a personal one. It’s the result of a healthcare culture that still doesn’t treat maternal mental health as central to maternal health. We deserve better.

So if you’re pregnant or postpartum, or supporting someone who is, and you know there’s a family history, bring it up. Advocate for a plan. Make space for mental health in your birth and parenting journey.

Because when moms are supported, everyone wins.

Related: 75% of women go untreated for postpartum mental health conditions

Need support?

If you or someone you love is experiencing distress during or after pregnancy, you are not alone. Maternal mental health challenges are real, but treatable—and compassionate help is available.

• Postpartum Support International (PSI) provides free, confidential support. Call or text the HelpLine at 1-800-944-4773 (4PPD). You can also text in English (send “HELP” to 800-944-4773) or Spanish (send “AYUDA” to 971-203-7773). Find local providers, peer support groups, and more at postpartum.net.
  
• National Maternal Mental Health Hotline (U.S. Department of Health & Human Services) is available 24/7. Call or text 1-833-9-HELP4MOMS (1-833-943-5746) to speak with counselors trained in maternal mental health. This service is free, confidential, and available in English and Spanish. Learn more at mchb.hrsa.gov.
  
• Moms Mental Health Initiative, a mom-founded nonprofit, offers peer-driven support, resource navigation, and advocacy for those struggling with perinatal mental health conditions. Visit momsmentalhealthmke.org to find tools, stories, and support tailored for mothers.
  
• In an emergency or immediate crisis—such as suicidal thoughts or feeling unsafe—call or text 988, the Suicide & Crisis Lifeline, or visit 988lifeline.org. You’ll be connected with trained counselors who are there to listen and help you stay safe.
  

Let’s keep breaking the silence around maternal mental health—because when we speak up, we help others find their way to healing too.