Pregnancy: The safety of desvenlafaxine in human pregnancy has not been established. Studies have demonstrated that desvenlafaxine crosses the human placenta. Desvenlafaxine must only be administered to pregnant women if the expected benefits outweigh the possible risks. If desvenlafaxine is used until, or shortly before birth, discontinuation effects in the newborn should be considered.
Complications, including the need for respiratory support, tube feeding or prolonged hospitalization, have been reported in neonates exposed to SNRIs or SSRIs late in the third trimester. Such complications can arise immediately upon delivery.
Data from the Quebec Pregnancy Cohort reported that, following exposure to SNRIs (including desvenlafaxine) during the second half of pregnancy, persistent pulmonary hypertension of the newborn (PPHN) was identified in 0.2% of all neonates; no statistical significance in the increased risk of PPHN in response to second/third trimester exposure could be established.
In a prospective, observational study, the median (interquartile range [IQR]) gestational age was higher in infants born to control mothers than those born to mothers treated with antidepressants (40 [39-40 weeks] vs. 39 [38-40 weeks]; p<0.05). Neonates born to control mothers also had a longer median (IQR) length at birth (51 [49-51.6] cm vs. 49 [47-51] cm; p<0.05) than infants born to mothers in the cases group. The infants also displayed mild behavioral anomalies, categorized as less optimal functioning for habituation and motor and autonomic clusters (using the Brazelton Neonatal Behavioral Assessment Scale [BNBAS]); however these events were self-limiting and usually resolved in 1 to 2 weeks.
In another study, 6 of the 7 neonates with in utero exposure to venlafaxine at near term had acceptable Apgar scores at birth; however an improvement in Apgar scores at 5 minutes was observed in all 7 neonates. No cases of intrauterine growth retardation were recorded. The adverse events observed in 5 neonates at birth, included respiratory distress, tachypnea, irritability, tremors, excessive suckling, rigidity, increased tonus, vomiting, hyper-reflexia, disorganized movements of limbs, initial decreased reactivity, agitation, poor sleep and liquid/abundant stool. In 4 of the 5 neonates, the events resolved spontaneously without the need for any pharmacological treatment, while one neonate required resuscitation and continuous positive airway pressure (C-PAP) for 48 hours. Although respiratory distress was attributed to the plasma concentration of venlafaxine or desvenlafaxine at birth, the occurrence of the other adverse events correlated with the declining levels of venlafaxine, suggests that these events could potentially signal withdrawal symptoms in the neonate following a decline in levels of venlafaxine after exposure to significantly high levels of the drug in utero.
A prospective longitudinal study of 201 women with a history of major depression who were euthymic at the beginning of pregnancy showed that women who discontinued antidepressant medication during pregnancy were more likely to experience a relapse of major depression than women who continued antidepressant medication.
Exposure to SNRIs in mid to late pregnancy may increase the risk for preeclampsia, and exposure to SNRIs near delivery may increase the risk for postpartum haemorrhage. Observational data indicate an increased risk (less than 2-fold) of postpartum haemorrhage following SSRl/SNRI exposure within the month prior to birth.
Lactation: Desvenlafaxine (O-desmethylvenlafaxine) is excreted in human milk. No adverse events occurred in either the lactating mothers or the nursing infants, however, the effect in infants have not been established. Desvenlafaxine should only be taken by lactating women if the expected benefits outweigh the possible risks.