Based on a 2015 systematic review, in 13 trials examining outcomes in babies breastfed by mothers taking fluoxetine, including a total of 280 patients, there were 7 reports of adverse events (5 patients with decreased postnatal growth and 2 patients with colic). Sertraline was found to have had more trials than fluoxetine (16 trials including a total of 279 patients) and no reported adverse events, leading this agent along with paroxetine to be considered first-line agents above other SSRIs for breastfeeding patients. That said, fluoxetine remains relatively safe for mothers and newborns while breastfeeding, and the consensus is that patients should not be discouraged from taking SSRIs while breastfeeding. Given this patient’s history of multiple depressive episodes and a suicide attempt, it would be particularly important to maintain her antidepressant regimen while postpartum rather than switch her to sertraline or stop her SSRI altogether. While sleep disruption with a newborn can increase the risk of precipitating mania, this would not be a reason to discourage breastfeeding in a patient with no known bipolar diathesis who has stated that she would prefer to breastfeed.

Publication reference : Stewart, Donna E., and Simone Vigod. "Postpartum depression." New England Journal of Medicine 375.22 (2016): 2177-2186.
Reference URL: https://www.ncbi.nlm.nih.gov/pubmed/27959754
Publication reference : Orsolini, Laura, and Cesario Bellantuono. "Serotonin reuptake inhibitors and breastfeeding: a systematic review." Human Psychopharmacology: Clinical and Experimental 30.1 (2015): 4-20.
Reference URL: https://www.ncbi.nlm.nih.gov/pubmed/25572308