Postpartum Bleeding in Pregnant Women Receiving SSRIs/SNRIs: New Insights From a Descriptive Observational Study and an Analysis of Data from the FAERS Database.

PURPOSE:To date, the available data on the relationship between the use of selective serotonin reuptake inhibitors (SSRIs) or the serotonin and norepinephrine reuptake inhibitor (SNRI) venlafaxine and postpartum hemorrhage (PPH) are conflicting and have not been extensively investigated, especially in terms of plasma drug concentrations. We performed data mining of antidepressant-induced PPH reported to the US Food and Drug Administration's Adverse Event Reporting System database, to assess the strength of the potential association between antidepressant pharmacotherapy and PPH in pregnant women. Concurrently, we carried out a descriptive observational population (pregnant women) analysis of the correlation between the plasma concentrations of SSRIs/SNRIs used during pregnancy and the extent of bleeding at delivery. METHODS:A disproportionality analysis of individual case study reports of PPH associated with SSRIs or venlafaxine in pregnant women was performed. Reporting odds ratio was used as a measure of disproportionality analysis. Pregnant women treated with an SSRI or SNRI (venlafaxine) for depressive or anxiety disorder and who consented to plasma drug concentration monitoring at the time of delivery were recruited. Plasma drug concentration assay was performed according to validated LC-MS/MS. Based on plasma drug concentrations, patients were classified into 1 of 2 groups, in therapeutic range or below therapeutic range for the drug administered, in accordance with the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie guideline, and correlations with blood loss were identified, with PPH defined as a blood loss of >500 mL. FINDINGS:Only 43 Individual Case Safety Reports (ICSRs) reported at least one SSRIs or venlafaxine as suspect drug in 14 years (database analyses). Forty-three women were enrolled in the study population (observational study). In 24 patients (55.8%) the plasma drug concentration was below the therapeutic threshold. Unexpectedly, the mean blood loss in the below-range group was significantly higher than that in the in-range group. PPH occurred in 30% of women: in 9.3% and in 20.7% of patients in the in-range and below-range groups, respectively. IMPLICATIONS:Although preliminary, these data indicate a rather good tolerability profile of SSRIs/SNRIs regarding postpartum bleeding. Moreover, they suggest that keeping the plasma levels of SSRIs/SNRIs low as a precautionary measure does not reduce postpartum bleeding, which was higher in the below-range group. The findings from this study suggest that the use of therapeutic drug monitoring in pregnancy, a period in which multiple variables affect drug metabolism, may allow for better treatment customization, with subsequent advantages in terms of tolerability and efficacy of treatment.