Side Effects: Smoking May Reduce Fertility in Women
Women who smoke may be reducing their chances of having a baby, a new study finds.
Exposure to even a small amount of a class of chemicals in cigarette smoke may destroy a woman's eggs in the ovaries, researchers wrote in last week's issue of Nature Genetics.
"I think there's an alarming connection that's going on here," said the lead author of the study, Dr. Jonathan L. Tilly of Massachusetts General Hospital and Harvard Medical School.
Smoking is already suspected of hastening the onset of menopause in some smokers. And fertility treatments are known to be less successful in women who smoke. The new study offers evidence why.
Chemicals in smoke known as polycyclic aromatic hydrocarbons, also created when fossil fuels are burned, spur the expression in the eggs of a gene called "bax." When this takes place, the eggs almost always die.
To prove their theory, researchers grafted sections of human ovaries into mice and then exposed them to the hydrocarbons. Even a single exposure, they reported, produced a marked increase in the number of eggs that were degenerating.
Apart from the implications for women hoping to conceive, the study may help explain why women who smoke seem to enter menopause several years earlier than the average age in the United States (about 50). The difference may be explained simply by the earlier death of the eggs, the researchers said.