CIGARETTES may actually be worse for a fetus than cocaine.
Both recreational teratogens are vasoconstrictors that, in similar ways, trigger hypoxia and ischemia, decreasing blood flow to the fetus and depriving it of oxygen and nutrition. "There is a great resemblance in their effects on brain development," says Theodore Slotkin, PhD, professor of pharmacology at Duke University School of Medicine, Durham, NC.
Yet animal studies show that nicotine has an additional effect on specific cholinergic receptors that develop during the third trimester of gestation and are involved in acetylcholine neurotransmission. "It's as though nicotine equals cocaine plus this additional effect" that cocaine does not have, says Slotkin. Rats exposed in his laboratory to constant low doses of nicotine equal to moderate smoking (one-half to one pack a day) by a human mother were born with far fewer of these nerve cells than normal, up to one third less in some