SSRIs during breastfeeding: spotlight on milk-to-plasma ratio

Arch Womens Ment Health. 2007;10(2):39-51. doi: 10.1007/s00737-007-0173-0. Epub 2007 Feb 12.


Objective: To investigate the usefulness of the milk-to-plasma (M/P) ratio for assessing the risks for the breastfed infant associated with the maternal use of SSRIs.

Data sources: Medline, Toxnet, Embase, Current Contents, and PsycInfo indexed articles from 1980 to September 2006.

Study selection and data extraction: All studies reporting the M/P ratio in mothers taking SSRIs while breastfeeding or studies which such an information could be calculated from data reported in the article.

Data synthesis: Higher M/P ratios were rarely associated with a clinically significant impact on the babies during the early phases of breastfeeding.

Conclusions: So far no evidence-based information seems to support the hypothesis that SSRIs characterized by a M/P ratio <1.0 should be preferred. Hence, physicians should consider different parameters when attempting to choose the safest SSRI for the breastfeeding woman. These parameters might be represented by the number of well-documented published adverse event reports and the tendency of each SSRI of inducing in the infants serum concentrations that are elevated above 10% of average maternal serum levels. In any case, if the mother wishes to breastfeed her infant while taking a SSRI, the baby should be closely monitored in order to promptly detect any iatrogenic event.

Publication types

  • Review

MeSH terms

  • Adult
  • Blood Platelets / metabolism
  • Breast Feeding*
  • Depressive Disorder / drug therapy*
  • Female
  • Fluoxetine / analogs & derivatives
  • Fluoxetine / pharmacokinetics*
  • Fluoxetine / therapeutic use
  • Half-Life
  • Humans
  • Infant
  • Infant, Newborn
  • Milk, Human / metabolism*
  • Puerperal Disorders / drug therapy*
  • Selective Serotonin Reuptake Inhibitors / pharmacokinetics*
  • Selective Serotonin Reuptake Inhibitors / therapeutic use
  • Serotonin / blood


  • Serotonin Uptake Inhibitors
  • Fluoxetine
  • Serotonin