Cigarette Smoke Toxin Makes Women Infertile

ByABC News
July 16, 2001, 11:25 AM

July 16 -- Women who smoke cigarettesinhale a toxin that can trigger ovarian failure, significantlydecreasing their reproductive years, scientists said on Sundayin the first study confirming a long-suspected link betweensmoking and female infertility.

Researchers led by Dr. Jonathan Tilly of MassachusettsGeneral Hospital in Boston said a chemical found in cigarettesmoke and some air pollution can trigger early menopause byaccelerating the destruction of the egg cells in ovaries.

Tilly and his colleagues studied the effect of Polycyclic Aromatic Hydrocarbons, known as PAH, on female miceover a six-year period. They injected the mice with the toxinand tracked a chain of chemical reactions that triggered thedeath of the rodents' egg cells.

The toxin attaches to receptors on the surface of the eggcells inside the uterus. That bond triggers a chemical reactionthat programs the eggs to die, the study found.

After confirming the effect the toxin had on the mice's eggcells, the scientists placed human ovary tissue under theanimals' skin. The eggs began to degenerate within three daysafter the toxin was injected, the study found.

Tilly said the destructive process is gradual and cannotimmediately be detected.

"You don't see any impact [from the chemicals] until manyyears down the road. The ovaries will continue to work, and thedestruction will go on for a while, and boom," Tilly said in atelephone interview.

The findings were published in the journal NatureGenetics.

Silent Killers

The toxin forms during the incomplete burning of coal orother substances such as charbroiled meat. PAHs also are usedto make tar, some medicines, plastics and dyes.

"It is accurate to refer to them as silent killers becausethey damage a population of cells, [which] we can't deter untilafter the fact when it's way too late," Tilly said.

When girls are born, they have a finite supply of eggs thatmature and are gradually released during ovulation. Continualexposure to the chemicals causes the eggs to die prematurely,resulting in early menopause, the researchers said.