Effects of varenicline usage on fetus and smoking cessation during pregnancy

Abstract<br> Background: Smoking causes several negative effects during pregnancy, such as premature birth, fetus growth delay, low birth weight, and sudden infant death syndrome. Therefore, smoking cessation is extremely important. There are two main types of smoking cessation treatment, namely behavioral therapy and drug treatment to treat nicotine dependence (through nicotine replacement therapy, treatment with oral smoking cessation aids, i.e., varenicline). Nicotine replacement therapy is contraindicated during pregnancy, but varenicline can be administered only if potential benefits outweigh the risks. Treatment involving varenicline is more effective than behavioral therapy alone; however, data on the safety to the fetus is insufficient.<br> Purpose: We studied varenicline usage during pregnancy at the Osaka Women’s and Children’s Hospital.<br> Method: Study subjects included 56 outpatients with a single pregnancy who had participated in a smoking cessation program two or more times at the Osaka Women’s and Children’s Hospital between 2004 and 2017. Among the 56 patients, six underwent drug treatment with varenicline (group V) and the remainder underwent behavioral therapy (group B). All items assessed were retrospectively extracted from patients’ medical charts.<br> Results: Varenicline was used in the first trimester in two cases and in the second trimester in four. No adverse events, such as external malformations of the fetus, were noted. Low-birth-weight infants were noted in two (33.3%) cases in group V and in seven (14.0%) in group B. Premature birth was noted in one (16.7%) case in group V and in one (2.0%) in group B. There were no significant differences in low-birth-weight infants and premature birth between the two groups. Five (83.3%) cases in group V and 14 (28.0%) in group B successfully quit smoking. These results indicate that significantly more patients successfully quit smoking in group V (p = 0.0068). Side effects of maternal varenicline included three cases of nausea and vomiting, one case of nightmares, and one case of palpitation.<br> Discussion:Our findings suggested that the risk of teratogenicity and fetal toxicity did not increase with varenicline usage. However, two cases of varenicline usage during the first trimester were conducted in nearly all or no terms; therefore, the possibility of no influence on teratogenicity exists. The results suggest that drug treatment using varenicline is more effective for maternal smoking cessation than is behavioral therapy alone.