Can I take mirtazapine while pregnant or breastfeeding?
A plain-words look at what the NHS, the US drug label and LactMed say about mirtazapine.
In short
Pregnancy: Let your doctor know if you're pregnant, or if you become pregnant while on mirtazapine.
Breastfeeding: Let your doctor know if you're breastfeeding.
Your doctor, midwife or pharmacist can help you decide.
What this means for you
Pregnancy
- If needed, mirtazapine can be used in pregnancy.
- Your doctor will discuss with you the risks and benefits of taking it while pregnant.
- You may be advised to have your baby in hospital, so that you and your baby can be monitored closely after the birth.
Breastfeeding
- Mirtazapine does sometimes get used during breastfeeding.
- Only very small amounts reach breast milk.
- Carrying on with it may be possible if the benefits are greater than any possible risks.
- Your doctor might suggest changing to another antidepressant instead.
When to get help
- Side effects from mirtazapine in breastfed babies are rare, but talk to a healthcare professional or call NHS 111 (in the UK) if anything about your baby worries you.
Talk to your doctor or pharmacist
This page is educational, not advice for your own situation. Talk to your doctor, midwife or pharmacist before you start, stop or change any medicine in pregnancy or while breastfeeding.
The details: what each source says
Mirtazapine in pregnancy
The NHS says
Let your doctor know if you're pregnant, or if you become pregnant while on mirtazapine.
If needed, mirtazapine can be used in pregnancy. Your doctor will discuss with you the risks and benefits of taking it while pregnant.
You may be advised to have your baby in hospital, so that you and your baby can be monitored closely after the birth.
In our words, from the NHS page Mirtazapine (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.
The US drug label says
Pregnancy Teratogenic Effects – Pregnancy Category C Reproduction studies in pregnant rats and rabbits at doses up to 100 mg/kg and 40 mg/kg, respectively [ 20 and 17 times the maximum recommended human dose (MRHD) on an mg/m 2 basis, respectively] , have revealed no evidence of teratogenic effects. However, in rats, there was an increase in postimplantation losses in dams treated with mirtazapine. There was an increase in pup deaths during the first 3 days of lactation and a decrease in pup birth weights. The cause of these deaths is not known. The effects occurred at doses that were 20 times the MRHD, but not at 3 times the MRHD, on an mg/m 2 basis. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Prescribing label, section “Pregnancy”: Mirtazapine (oral), ATLANTIC BIOLOGICALS CORP. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.
More on mirtazapine in pregnancy: Bumps (Best Use of Medicines in Pregnancy) leaflet (external site).
Mirtazapine while breastfeeding
The NHS says
Let your doctor know if you're breastfeeding.
Mirtazapine does sometimes get used during breastfeeding. Only very small amounts reach breast milk.
Carrying on with it may be possible if the benefits are greater than any possible risks. Your doctor might suggest changing to another antidepressant instead.
Side effects from mirtazapine in breastfed babies are rare, but talk to a healthcare professional or call NHS 111 (in the UK) if anything about your baby worries you.
In our words, from the NHS page Mirtazapine (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.
LactMed says
Limited information indicates that maternal doses of up to 120 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. If mirtazapine is required by the mother, it is not a reason to discontinue breastfeeding. A safety scoring system finds mirtazapine use to be possible during breastfeeding.[1] Exclusively breastfed infants should be monitored for behavioral side effects and adequate growth if this drug is used during lactation.
“Summary of Use during Lactation”, LactMed record “Mirtazapine” (LM325), quoted verbatim. Everything LactMed reports about Mirtazapine while breastfeeding.
The US prescribing label says
Nursing Mothers Because some mirtazapine may be excreted into breast milk, caution should be exercised when mirtazapine tablets are administered to nursing women.
Prescribing label, section “Nursing Mothers”: Mirtazapine (oral), ATLANTIC BIOLOGICALS CORP. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.
Sources
- NHS, Mirtazapine (nhs.uk), page last reviewed 18 August 2026. Paraphrased. Contains public sector information licensed under the Open Government Licence v3.0.
- US drug label: Mirtazapine (oral), ATLANTIC BIOLOGICALS CORP., human prescription drug, label effective 27 June 2025, set ID e6e5cbf7-a958-4ef8-abcc-a7491edb9520. DailyMed (National Library of Medicine). Public domain; quoted verbatim.
- Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Mirtazapine” (LM325), bulk release of 22 September 2026. LactMed on NCBI Bookshelf. Public domain; quoted verbatim. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
- Bumps (Best Use of Medicines in Pregnancy), UK Teratology Information Service: Bumps (Best Use of Medicines in Pregnancy) leaflet. Linked, not reproduced.
Sources checked 26 September 2026. How we source and check every page.
Educational summary of named sources, not medical advice.