Postpartum Depression Treatment: Antidepressant Side Effects During Lactation

Nov, 10 2025

When a new mom is struggling with postpartum depression, the last thing she should have to choose between is her mental health and her ability to breastfeed. But too often, that’s exactly the impossible choice she’s faced with. The fear of harming her baby with medication can silence her cries for help-even when she’s too exhausted to hold her child, too numb to smile, or too overwhelmed to even feed herself. The truth? Antidepressants are not only safe for most breastfeeding mothers-they’re often essential.

Why Untreated Depression Is Riskier Than Medication

It’s easy to assume that any drug entering breast milk is dangerous. But the real danger isn’t the medication-it’s the silence. Untreated postpartum depression doesn’t just affect the mother. It impacts bonding, feeding patterns, sleep cycles, and even the baby’s long-term emotional development. The CDC, the American College of Obstetricians and Gynecologists (ACOG), and the American Academy of Pediatrics all agree: the risks of leaving PPD untreated far outweigh the theoretical risks of most antidepressants in breast milk.

Studies show that babies of mothers with untreated depression are more likely to have delayed language development, poor weight gain, and increased irritability. Meanwhile, when a mother gets effective treatment, she’s more likely to respond to her baby’s cues, maintain feeding routines, and form secure attachments. That’s why doctors don’t tell women to stop breastfeeding-they tell them to treat the depression while breastfeeding.

Which Antidepressants Are Safest While Breastfeeding?

Not all antidepressants are created equal when it comes to lactation. The key metric doctors use is the relative infant dose (RID)-how much of the mother’s medication actually reaches the baby through breast milk, adjusted for the baby’s weight. Anything under 10% RID is generally considered safe.

Sertraline is the gold standard. It transfers at just 0.5% to 3.2% of the mother’s dose into breast milk. In over 1,800 mother-baby pairs studied, 92% of infants had undetectable levels in their blood. Most moms report no changes in their babies’ behavior, feeding, or sleep. Many say sertraline gave them back their ability to hold their child without crying.

Paroxetine is another top choice. It has slightly higher transfer (up to 8.6%), but still falls well under the 10% safety threshold. It’s fast-acting and often used when quick relief is needed. Some moms notice mild fussiness at first, but it usually fades within a week.

Citalopram and escitalopram are moderate options. Transfer is around 3.5% to 8.9%. They’re effective, but doctors tend to avoid higher doses (over 20mg daily) because of rare reports of heart rhythm changes in infants.

Venlafaxine and mirtazapine are used less often but still considered acceptable. Transfer is low to moderate, but there are occasional reports of irritability or poor feeding-especially at doses above 150mg. These are usually second-line options if SSRIs don’t work.

Antidepressants to Avoid During Lactation

Some medications carry higher risks-and those risks aren’t theoretical.

Fluoxetine (Prozac) is the most problematic. It has a long half-life and builds up in the baby’s system. Transfer rates range from 5.9% to 15.2%, and its active metabolite, norfluoxetine, can reach up to 30% of the mother’s concentration in the infant’s blood. This can cause excessive sleepiness, poor feeding, or even jitteriness in newborns. It’s not forbidden, but it’s not first-line either.

Doxepin has been linked to serious infant reactions: apnea, cyanosis (blue skin), and sudden breathing pauses-even at low maternal doses of 75mg. The Breastfeeding Network explicitly recommends avoiding it.

Bupropion (Wellbutrin) carries a small but real risk of seizures in infants, especially those under 2 months or with neurological conditions. While transfer is low (6-10%), the consequences are severe enough that most specialists avoid it unless no other option exists.

A mother reviews medication information at the kitchen table while her baby sleeps nearby.

What About Newer Drugs Like Zuranolone?

Zurzuvae (zuranolone), approved by the FDA in August 2023, is the first oral drug specifically designed for postpartum depression. It works fast-many women feel better in under two weeks. But here’s the catch: the original clinical trials required women to stop breastfeeding during treatment.

However, data from LactMed shows zuranolone transfers into breast milk at very low levels-only 0.5% to 1.5% of the maternal dose. Experts believe it’s unlikely to harm the baby. Still, ACOG currently recommends pumping and discarding milk for one week after the last dose, just to be safe. That’s a temporary pause, not a permanent stop. Many moms find this acceptable, especially since the treatment lasts only two weeks.

How to Minimize Baby’s Exposure

Even with the safest medications, you can take steps to reduce your baby’s exposure even further:

Take your dose right after breastfeeding, not before. This gives your body time to clear the medication before the next feeding.
Use the lowest effective dose. Start low-25mg of sertraline, 10mg of paroxetine-and only increase if needed.
Monitor your baby closely during the first two weeks. Look for signs like excessive sleepiness, poor feeding, irritability, or unusual crying.
Don’t stop abruptly. Stopping antidepressants suddenly increases your risk of relapse by three times.

Most side effects in babies are mild and temporary. In a 2021 survey of 347 breastfeeding mothers on antidepressants, 86% reported no noticeable effects on their infants. Of the 14% who noticed changes, most were minor-like a few days of fussiness or slightly less sleep. These often resolved with a small dose adjustment.

A group of mothers laugh together in a living room, bonding over shared experiences with their babies.

What to Watch For-and When to Call Your Doctor

Your baby is not a lab rat. Their reactions matter. Watch for:

Excessive sleepiness (hard to wake for feeds)
Poor feeding or refusal to nurse
Unusual crying or irritability that doesn’t improve
Poor weight gain or vomiting

If you notice any of these, don’t panic. Call your doctor or lactation consultant. In most cases, switching to a different medication (like from fluoxetine to sertraline) solves the issue. One mom on a parenting forum shared that her daughter had explosive diarrhea for weeks until she switched from fluoxetine to sertraline-then it stopped overnight.

Also, be aware of your own symptoms. If your depression worsens or you have thoughts of harming yourself or your baby, reach out immediately. Medication isn’t a cure-all-it’s a tool. Therapy, support groups, sleep help, and partner involvement are just as important.

Resources You Can Trust

You don’t have to guess. Reliable, up-to-date information exists:

LactMed (from the National Library of Medicine): Updated weekly, free, and evidence-based. Search any medication and get transfer rates, safety ratings, and infant risk summaries.
InfantRisk Center: Offers a free hotline (806-352-2519) staffed by pharmacists who specialize in lactation. They answer over 3,000 calls a month.
Postpartum Support International: Offers peer support, local groups, and provider directories. Their online forums are full of real stories from moms who’ve been there.

These aren’t just websites-they’re lifelines. Use them.

You’re Not Alone

You didn’t fail because you needed medication. You didn’t fail because you’re breastfeeding and taking antidepressants. You’re doing something incredibly hard-and you’re doing it with your baby’s health in mind. That’s strength.

Thousands of mothers are on sertraline right now, holding their babies, feeding them, and sleeping through the night for the first time in months. Their babies are thriving. Their hearts are healing. And so can yours.

Treatment isn’t about perfection. It’s about progress. One pill. One feed. One day at a time.