January 2, 2006
Nicotine substitutes may harm the fetus: study
NEW YORK (Reuters Health) - The use of nicotine substitutes
(nicotine gum, patches or inhalers) during the first 12 weeks
of pregnancy appears to slightly increase the risk of birth
defects, according to a large study of pregnant women and their
Dr. Maria M. Morales-Suarez-Varela, from the University of
Valencia in Spain, and others interviewed 76,768 women between
weeks 11 and 25 of pregnancy regarding their smoking habits and
use of nicotine replacement products during the first 12 weeks.
There were 20,603 pregnancies resulting in live births of
mothers who smoked cigarettes and 56,165 among mothers who did
The authors observed a "relative prevalence rate ratio" or
RPR, of 1.1 for all congenital malformations among smokers. The
RPR for cleft lip or malformations of the digestive system or
circulatory system ranged between 1.2 and 1.5.
Among nonsmokers who used nicotine substitutes during the
first 12 weeks, the RPR for birth defects was higher -- 1.61 --
compared with nonsmokers who did not use nicotine substitutes.
The RPR for musculoskeletal type malformations was 2.63.
To explain these discrepancies, the researchers offer that
nicotine substitutes may be absorbed by a different route and
reach higher peak doses of nicotine compared with tobacco
Even though their study failed to find increased
malformation risk among smokers, the researchers say that
"there is sufficient evidence for a harmful, overall fetotoxic
effect of smoking to warn pregnant women not to smoke at all
They recommend further study to confirm the potential role
of nicotine substitutes in causing congenital malformations.
SOURCE: Obstetrics and Gynecology January 2006.