Chantix was tested in rats and rabbits at oral doses of up to 50-times the maximum recommended dose for humans and found not to cause birth defects in rats or rabbits. Although Chantix did, cause reduced fetal weight in the offspring of pregnant rabbits.
There are no adequate and well-controlled studies in pregnant women. Therefore, the potential effects of Chantix on labor and delivery are not known.
Current Categories for Drug Use in Pregnancy
Category A : Adequate, well-controlled studies in pregnant women have not shown an increased risk of fetal abnormalities.
Category B : Animal studies have revealed no evidence of harm to the fetus, however, there are no adequate and well-controlled studies in pregnant women or animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus.
Category C : Animal studies have shown an adverse effect and there are no adequate and well-controlled studies in pregnant women or no animal studies conducted and there are no adequate and well-controlled studies in pregnant women.
Category D : Studies, adequate well-controlled or observational, in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy may outweigh the potential risk.
Category X : Studies, adequate well-controlled or observational, in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. The use of the product is contraindicated in women who are or may become pregnant.
Chantix (varenicline) is classified as a pregnancy category C drug.
If you asked me if I would want my mother taking Chantix, while pregnant with me. I would answer no but then again I would not want her smoking either.
Clearly, there is a knowledge gap about Chantix’s use during pregnancy, so there is no way to know with total certainty whether or not one should take Chantix during pregnancy.