Table of Contents

How Is the Safety of Psychiatric Medications in Breastfeeding Determined?

Determining the safety of psychiatric medications during lactation relies on a multifaceted evaluation, combining pharmacological data with clinical outcomes and expert consensus. The main elements used in these determinations include:

• Measured Drug Levels: Rigorous studies assess drug concentrations in maternal plasma, breast milk, and, when possible, infant plasma. The finding of low or undetectable infant plasma levels—despite measurable amounts in breast milk—provides important reassurance regarding infant safety.
  
• Milk-to-Plasma (M/P) Ratio: This pharmacokinetic value estimates how much drug transfers from maternal blood into breast milk. Calculated as the concentration of drug in breast milk divided by that in maternal plasma, an M/P ratio below 1 typically signifies limited drug passage and is considered favorable for breastfeeding safety.
  
• Relative Infant Dose (RID): RID is an estimate that incorporates the M/P ratio and the body weights of both mother and infant, providing an approximation of the amount of medication the infant receives via breast milk. A relative infant dose below 10% of the maternal weight-adjusted dose is generally regarded as acceptable.
  
• Case Series & Adverse Event Reports: Published case reports, case series, and data from national registries are reviewed for adverse effects (such as sedation or feeding problems) in exposed infants. The frequency and severity of reported events, relative to the overall number of exposed infants, play a central role in risk assessment.
  
• Consensus and Guidelines: Professional organizations—such as the American College of Obstetricians and Gynecologists (ACOG), the American Academy of Family Physicians (AAFP), and LactMed—periodically review and synthesize pooled evidence to create clinical recommendations. These guidelines weigh both pharmacological data and real-world outcomes.

To integrate these elements more formally, Uguz has proposed a safety scoring system which rates the safety of psychotropic medications in lactation based on six key parameters: size of the total sample reported, maximum RID, sample size reporting RID, infant plasma levels, prevalence of reported adverse events, and severity of any serious adverse events. This system generates a total score (ranging from 0 to 10), with higher scores representing a more robust safety profile and a greater assurance of compatibility with breastfeeding.

This comprehensive approach helps guide clinicians and patients in making informed, individualized decisions about psychiatric medication use during breastfeeding, balancing the known benefits of maternal mental health treatment with the best available evidence on infant safety.

General Principles

• Medication Transfer into Breast Milk:  All psychiatric medication, including antidepressants, antipsychotics, mood stabilizers, and benzodiazepines, are excreted into breast milk, but the amount present and the degree of infant exposure can vary widely depending on the specific drug and individual maternal factors.
  
• Special Considerations for Premature or Medically Vulnerable Infants:
  Premature infants or those with underlying medical conditions, such as impaired hepatic function, have a reduced ability to metabolize and eliminate medications, making them more vulnerable to potential toxicity from drugs in breast milk.
  
• Monitoring and Collaboration with Pediatrician: Routine drug-level monitoring in infants is generally not required for healthy, full-term babies, but should be considered if symptoms suggest medication toxicity or if the mother is taking a higher dose than typical. Collaboration with the infant’s pediatrician is recommended to ensure ongoing, individualized monitoring and care.
  
• Research Limitations:  While research has improved our understanding of the immediate and short-term effects of medication exposure via breast milk, data on long-term developmental outcomes remain limited. Individualized and vigilant clinical decision-making is essential to balance the benefits of maternal treatment and breastfeeding against any potential risks to the infant.

Antidepressants

• SSRIs and Tricyclic Antidepressants (TCAs):  Selective serotonin reuptake inhibitors (SSRIs)—including sertraline, paroxetine, and fluoxetine—as well as tricyclic antidepressants (TCAs), are among the best-studied and most reassuring medications for use in breastfeeding women. Multiple studies have documented low concentrations of these medications in breast milk, with undetectable or very low serum drug levels found in infants. Adverse events are rare.
  
• Other Antidepressants:  There is less data regarding the use of other antidepressants, such as venlafaxine, duloxetine, mirtazapine, and trazodone. While SSRIs and TCAs remain the preferred choices due to their established safety profiles, these alternatives may also be considered when clinically warranted, provided there is careful monitoring of the infant.
  
• Adverse Effect Reports:  Case reports describing jitteriness, irritability, and feeding or sleep disturbances in infants exposed to antidepressants through breast milk have been published. However, causality is often difficult to determine in these cases, and such adverse effects appear to be uncommon.
  
• Recent Expert Consensus:  Recent guidelines indicate that there is little evidence of significant harm from antidepressant exposure in breast milk. Importantly, the negative impact of untreated maternal depression far outweighs the theoretical risks associated with antidepressant use during lactation.
  

Anti-Anxiety Medications (Benzodiazepines)

• Breast Milk Transfer: Commonly used benzodiazepines—including lorazepam and clonazepam—are present at low levels in breast milk.
• Risks of Adverse Effects: Although adverse effects are rarely reported, there is a potential risk for infant sedation and feeding difficulties, particularly with higher doses or longer-acting agents. Shortest-acting benzodiazepines, used at the lowest effective dose and for the shortest possible duration, are generally preferred when treatment is needed.
• Monitoring and Clinical Guidance: Routine monitoring for signs of infant sedation and feeding issues is recommended during maternal benzodiazepine use. In most clinical situations, benzodiazepines are not considered a contraindication to breastfeeding.  
• Recent Expert Consensus: Recent guidelines support the use of benzodiazepines during breastfeeding for short-term management of anxiety or sleep disturbance. They indicate that there is little evidence of significant harm from benzodiazepine exposure in breast milk.

Mood Stabilizers

• Lithium: Lithium is secreted into the breast milk at relatively high levels, and serum levels in the nursing infant reach up to 1/3–1/2 of maternal serum levels. Close monitoring of maternal and infant lithium levels, renal, and thyroid function is required if used.
  
• Lamotrigine: Recent studies show variable infant serum levels (20–50% of maternal levels). No serious adverse events, including Stevens-Johnson syndrome, have been reported in exposed breastfeeding infants, but ongoing monitoring and consultation with a pediatrician is indicated.
  
• Carbamazepine and valproic acid: These mood stabilizers should be used with caution, with recommended infant liver function monitoring due to rare reports of neonatal hepatotoxicity.

Antipsychotic Medications

First-Generation Antipsychotics

• First-generation antipsychotics, including  haloperidol, chlorpromazine: Well-studied, generally considered compatible with breastfeeding in moderate doses, with low milk-to-plasma ratios.
  

Atypical (Second-Generation) Antipsychotics

• Olanzapine: Remains the best-studied atypical antipsychotic for lactation, with nearly 40 infant exposures reported. Maternal doses up to 20 mg/day generally yield low breast milk and negligible serum infant levels. Adverse events are rare and mild (occasional sedation), with unclear causality. 
• Quetiapine: Maternal quetiapine doses of up to 400 mg daily produce doses in milk that are less than 1% of the maternal weight-adjusted dosage. Limited long-term follow-up of infants exposed to quetiapine indicates that infants generally developed normally. 
• Risperidone:  Maternal risperidone doses of up to 6 mg daily produce low levels in milk. Adverse events have been reported, including sedation, failure to thrive, jitteriness, and abnormal muscle movements, in infants exposed to risperidone in milk; however, causality cannot be confirmed.
• Aripiprazole: Case reports suggest low transfer of aripiprazole into breast milk (with maternal doses up to 15 mg per day).  Aripiprazole can lower serum prolactin in a dose-related manner. Cases of lactation cessation have been reported. In a study of 35 women taking aripiprazole (mean dose of 16.4 mg/day), 26 (74%) experienced complete lactation failure, and 4 (11%) had insufficient milk production. Thus, when aripiprazole is used in nursing mothers, infants should be monitored for feeding issues and inadequate weight gain.
• Lurasidone, ziprasidone, clozapine: Extremely limited or no data for lactation is available. Clozapine remains contraindicated due to risk of agranulocytosis; breastfeeding should be avoided if using clozapine.

ADHD Medications

For women with milder forms of ADHD, we would most commonly recommend limiting the use of stimulants while breastfeeding.  However, women with more severe symptoms may require treatment.  Data regarding the use of therapeutic doses of methylphenidate and amphetamines is generally reassuring. Previous studies have suggested that methylphenidate and amphetamines may reduce serum prolactin; however, no studies have assessed the effect of methylphenidate and amphetamines on milk production.

• Methylphenidate (Ritalin, Concerta): Methylphenidate is present in breast milk at very low concentrations, with relative infant doses generally less than 1% of the maternal weight-adjusted dose. Most case reports and analyses have found no adverse events or developmental concerns in infants exposed to methylphenidate through breastmilk.
• Amphetamines (Dextroamphetamine, Adderall): Recent evidence indicates that amphetamines appear at low levels in milk, and infant blood concentrations are typically very low or undetectable. 
• Non-Stimulant Medications: Data remain limited for non-stimulant agents like atomoxetine, guanfacine, and clonidine. Guanfacine and clonidine may enter milk significantly and could reduce milk supply due to their physiological effects. If such medications are used, infants should be monitored for sedation or feeding issues, and alternative agents may be considered where possible 10.
• Clinical Recommendations and Practical Updates:
  • Use the lowest effective dose and immediate-release formulations when possible, allowing timing strategies to minimize infant exposure.
  • Milk supply concerns may be most significant in the immediate postpartum period and with high doses of medication.
  • Monitor infants for irritability, poor feeding, sleep changes, or growth concerns, especially when starting or increasing therapy.
  • For established lactation and older infants, risk appears lower.

Read More: Essential Reads: Breastfeeding and ADHD Medications

Clinical Decision-Making and Guidelines

• Weigh personalized risks and benefits: Consider the severity of illness in the mother, history of medication response, and her desire and/or ability to breastfeed.
• Continuation of medications used during pregnancy: Guidelines recommend that medications used during pregnancy, if effective, should be continued during the postpartum period.  Switching medications at this vulnerable time could increase risk for postpartum relapse. Decisions must consider the specific risks associated with exposure to a particular medication against risks of relapse in the mother.
• Choice of Medications: For breastfeeding women, the selection of medication depends on symptoms in the mother, past response to specific medications, prioritizing  medications with the most robust data and lowest risk of adverse events.
• Routine monitoring and collaboration with pediatrician: Infants of breast feeding mothers should be monitored according to standard guidelines, with attention to feeding problems, sedation, sleep changes, irritability, and jitteriness.
• Infant monitoring when necessary: Obtain infant drug levels or suspend breastfeeding if there is evidence of clinical toxicity (e.g., sedation, feeding difficulties) arises. While most medications do not require specific monitoring, the use of lithium requires period lithium levels and tests of renal and thyroid functioning in the infant. 
  
• Refer to updated sources: Consult LactMed for the latest data and recommendations. Information on the use of specific medications in nursing mothers can be found in the product label (Section 8.3).
  
• Support for mothers: Consider maternal health and preferences. For some women with severe illness, a reduction in breast feeding and supplementation or replacement with formula feeding may maximize maternal health and stability.

Seeking Care

Women on psychiatric medications who are breastfeeding or planning to breastfeed may benefit from a comprehensive evaluation by a perinatal psychiatrist or mental health provider to discuss the use of psychiatric medications while breastfeeding.  If you are in or near the Boston area or Massachusetts, you may schedule a consultation at the MGH Center for Women’s Mental Health by contacting our intake coordinator at 617-724-7792.

For those looking for a provider outside of the Boston area, Postpartum Support International maintains a Directory of Healthcare Providers caring for pregnant and postpartum individuals with psychiatric illness.

Other resources may be found on our RESOURCES PAGE.

Research Opportunities

There are currently no active studies for Breastfeeding & Medications at the Center. Learn more about our RESEARCH PROGRAM.

References

Anderson PO. Antidepressants and breastfeeding. Breastfeed Med. 2021;16(1):5-7.

A Collaborative Approach: How to Talk to Your Provider About Medications and Breastfeeding. [Internet] 

Consensus panel recommendations for the pharmacological management of breastfeeding women with postpartum depression. J Clin Psychiatry. 2024;85(3):24ac15246.

Drugs and Lactation Database (LactMed). National Library of Medicine; 2006. 

National Health Service–North West England. Psychotropic medications in the perinatal period. NHS England. 2025.

University of Illinois at Chicago. Information for Providers on Antipsychotics during Pregnancy and Breastfeeding. [Internet] 

Uguz F. A new safety scoring system for the use of psychotropic drugs during lactation. Am J Ther. 2021;28(1):e118-e126.

All pregnant women between the ages of 18-45 with a history of psychiatric illness are eligible to enroll in the registry.

Are you pregnant? Do you own a smart phone? Get the MGH Perinatal Depression Scale app.