Effexor (Venlafaxine) is classified as FDA pregnancy risk category C.
Pregnancy categories include A, B, C, D and X. Level A is considered to be safe while level X is considered to be a significant risk.
Category C essentially means there are either no studies or there are conflicting studies on the possible effects.
The general recommendation is that venlafaxine should be used in pregnancy only where the benefit to the mother clearly outweighs any potential risk to the fetus. Alternative agents should be considered by both the doctor and patient. If the doctor and patient decide to continue venlafaxine during pregnancy, discontinuation symptoms should be considered in the newborn at birth. New borns exposed to antidepressants that affect the neurotransmitter serotonin (which would include venlafaxine) late in the third trimester have developed complications requiring prolonged hospitalization. Such complications can arise immediately upon delivery. Symptoms have included respiratory distress, temperature instability, feeding difficulty, vomiting, hypoglycemia, and constant crying.
Animal studies have failed to show an increased risk of fetal malformations or adverse effects on male or female fertility. However, an increase in stillbirths, low birth-weight, and pup deaths postnatally has been noted when venlafaxine was given throughout gestation and continued during lactation.
Women often ask if if antidepressants are safe during pregnancy in general. I often hear from women that they are concerned that antidepressants are linked with miscarriages, preterm birth, and autism. Everything is quite controversial. Study results are conflicting.
The main point is that stopping a needed antidepressant can be risky. Untreated depression increases the risk of small birth size and preterm birth
It is important for women weigh the risks and benefits of antidepressants during pregnancy.
One option may be to try a drug like Zoloft (Sertraline) line. Sertraline has a good safety record in pregnancy, is usually well tolerated, and is poorly secreted into breast milk.