Chick embryonic development following exposure to caffeine and nicotine.

Because cigarette smoking is considered to be deleterious to the fetus and caffeine is held in suspect as a potential human teratogen, the combined effects of caffeine and nicotine on early chick embryos were investigated. Treatment of the embryos at 48 h incubation with both caffeine (1 mg) and nicotine (1 mg) resulted in a high incidence of embryonic death and developmental defects. At 72 h incubation teratogenicity was potentiated following the same treatment. Embryonic growth was not affected. Embryotoxic interactions of this nature might account for congenital anomalies of doubtful etiology.