Effexor and pregnancy do not mix. If you are pregnant, or think you might become pregnant in the future, this drug is not for you. Doctors do not know the adverse effects Effexor may have on an unborn baby. However, it is know that the drug can be dangerous for the mother. Increased thoughts of suicide and anxiety certainly will not help an unborn baby to thrive. In addition, the drug is known to cause weight loss, which is definitely a bad thing, if you are pregnant. In addition, the drug is so powerful, with so many potentially harmful side effects; the FDA has given it a black box warning, instead of simply taking it off the market all together.