Taking antibiotics such as ampicillin and painkillers like Tylenol in the early stage of pregnancy has virtually no effect on the likelihood of giving birth to a deformed baby, a study suggests.

Dr. Han Jung-yeol at Cheil General Hospital and Women's Healthcare Center compared 3,328 pregnant women who were exposed to such drugs in the 3.5-4.6 weeks of pregnancy between November 1999 and October 2008 to 2,545 without exposure. The study rendered no statistically significant results, with 2.5 percent of the exposed group and 2.9 percent of the unexposed group bearing congenitally malformed babies.

Nor did the two groups show any meaningful difference in giving birth prematurely before the 37th week of pregnancy, having babies under 2.5 kg, and miscarriage after 20 weeks.

The medication pregnant women were most frequently exposed to in the early stage of pregnancy was acetaminophen, used to alleviate fever and kill pain, antihistamine, widely used to treat allergies, vasodilator used for bronchitis, and gastric antisecretory drugs.

"About 450,000 abortions are reported every year in Korea, 13 percent of them being due to drug intake in the early stage of pregnancy," Han said. "Pregnant women are overly anxious about the risk of having deformed babies after taking drugs when the likelihood is minimal. Furthermore, some doctors fail to give appropriate explanations on drugs and recommend abortions."