Effexor is a Cat C drug, crosses the placenta near the end of pregnancy..there is an
increase chance of low birth weight and unknown demise (very low, but there). It will show up in your breast milk. Being a Cat C, it is considered safe to a point (which apparently is third trimester).
NEONATAL SIDE EFFECTS: Restlessness, hypertonia, jitteriness, irritability and poor feeding occurred in a neonate after maternal use of venlafaxine for depression during pregnancy.