Scientific evidence shows the offspring of pregnant women who smoke or are exposed to high levels of stress could suffer sexual problems later in life.

The new information is extrapolated from a study of rats presented this week to the joint fall meeting of the American Physiological Society and the American Society for Pharmacology and Experimental Therapeutics.Fleur Strand, one of the three endocrinologists from New York University who conducted the study, said the results should be viewed as a warning to pregnant women because both rat and human fetuses are extremely sensitive to changes in their environment.

The study involved innoculating pregnant rats with either nicotine or adrenocorticotropic hormone, or ACTH, a substance released by the pituitary gland during episodes of stress.

"Nicotine and high stress, such as that involved in wife battering, are very important hazards that pregnant females should be aware of," Strand said in an interview. "Up to now the effects of nicotine and stress on pregnant women or animals was believed to be short-term, such as lower weight at birth.

"Our study shows there are long-term, irreversible effects, which might not become apparent until puberty," Strand said.

The only way to prove scientifically the effects of stress and nicotine on pregnant women would be to do long-term studies of their offspring, Strand said, adding, "That would be difficult and expensive. What we're saying now (based on the rat study) is to be cautious."

In the study, the female offspring of the pregnant rats injected with either nicotine or ACTH reached puberty later than normal - and had a shorter fertile period, or estrous cycle, than normal female rats.

The researchers, who included Annabell Segarra and Cheung Wong, found that female rats whose mothers had been injected with nicotine also stopped ovulating.

Among the male rats whose mothers had been exposed to either nicotine or ACTH, 50 percent showed no interest in the opposite sex after reaching puberty at two months of age. Another 25 percent showed decreased sexual behavior. Only 10 percent of the male rats exhibited a normal sex drive.