Pregnancy Wisdom Questioned: Are Alcohol, Caffeine Really Off Limits?

ABC News' Amanda Keegan reports:

Emily Oster, author of "Expecting Better: Why the Conventional Pregnancy Wisdom Is Wrong-and What You Really Need to Know," is challenging the conventional wisdom of pregnancy and what's really off limits for women who are expecting.

Oster, a Chicago economist, used her love of statistics to comb through hundreds of pregnancy studies, drawing her own conclusions about those age-old pregnancy Do's and Don'ts, including alcohol, caffeine and exercise.

"I found the conflicting advice that I got overwhelming and I wanted to get to the real facts," Oster told ABC News.

Rule number one: Occasional adult beverages are off limits.

Not true says Oster.

"I found that evidence overwhelmingly suggested that having an occasional drink, even maybe a glass of wine a day, is not dangerous," she said.

Rule number two: Pregnant women should cut out their morning cup of Joe.

Again, according to Oster, this is not true.

"I found that caffeine in moderation is also fine," she explained. "Something like two to four cups a day, depending on how cautious you want to be."

Rule number three: Working in your yard could harm your baby.

True, says Oster. "There is some risk to increase birth defects if you do a lot of outdoor gardening when you are pregnant," she said. "That can increase rates of toxoplasmosis."

Oster is not a medical doctor and many obstetricians disagree with her collective findings, especially on alcohol.

"There is no amount of alcohol in pregnancies that should be considered safe," said Dr. Donnica Moore, president of Sapphire Women's Health Group. "Anything that the mother ingests goes through the placenta and the blood stream to the fetus."

ABC senior medical contributor Dr. Jennifer Ashton agrees there are many factors to take into consideration when making these decisions while pregnant.

"In general, it's very important for people to understand there's a lot more to practicing medicine than crunching numbers," Ashton explained. "What are the risks are doing something? What are the risks of not doing something?"

Take it or leave it, Oster hopes her research helps pregnant women draw their own conclusions.

"I think it is very important for women to take their pregnancy into their own hands and make decisions for themselves," said Oster.

Oster's book hits shelves on August 20.