Abstaining from alcohol and avoiding sushi or raw-milk cheeses are just some examples of the typical advice given to expectant mothers that an award-winning economist examines in a new book that's raising controversy.

Emily Oster, an associate professor of economics from the University of Chicago, told CTV's Canada AM that the aim of her new book, "Expecting Better: Why the Conventional Pregnancy Wisdom is Wrong and What You Really Need to Know," is to provide readers with the data behind some of the advice offered to expectant mothers.

Oster said that she decided to examine the evidence behind the recommendations after becoming pregnant herself.

"I got pregnant and like a lot of women, I found myself facing a lot of decisions and choices that I hadn't really thought about like: 'Could I have a cup of coffee?' and also 'Should I get an epidural?" she said Thursday.

"I quickly realized that these rules and recommendations were based on studies and data, and actually my training in economics is all about evaluating studies and data and making decisions based on that."

Oster used her training as an economist to look at hundreds of pregnancy studies and the evidence behind some of the commonplace lifestyle tips given to pregnant women, and drew a number of conclusions on issues including:

  • weight gain (starting weight may be more important than weight gain )
  • foods to avoid (sushi is ok, but stay away from raw-milk cheese)
  • activities to avoid (avoid hot yoga, hot tubs and hot baths)
  • and alcohol consumption (the occasional glass of wine is fine)

"I sort of took my job into my pregnancy and ultimately the book is the result," she said.

But Oster's claim that it is ok for women to have the occasional glass of wine while pregnant -- up to two glasses a week in the first trimester and up to a glass a day in the second and third trimesters – that's drawn the fiercest criticism from medical professionals.

Dr. Gideon Koren, director of the Motherisk program at the Hospital for Sick Children, said that there's no need for women to drink alcohol while pregnant and that the guidelines against drinking are there for a reason.

Koren said it's not easy to measure the effects of alcohol consumption during pregnancy on babies, as many of the effects aren't seen until the child is older and in school.

He also said that some expecting mothers, who are problem drinkers, might misinterpret the data and drink too much alcohol. He added that between three to five per cent of babies who are born to mothers who drank during their pregnancy develop health problems later in their lives.

Oster, who says she had the occasional glass of wine during her pregnancy and now has a healthy two-year-old girl, said that she recognizes the dangers of binge drinking while pregnant.

"Binge drinking, heavy drinking, even a couple of times in pregnancy can be very dangerous and I think that's very important no to lose sight of," she said. "Having said that, when we look at the data on women who drink occasionally during their pregnancy, we do not see any additional complications for their children on a variety of dimensions."

She stressed that her book is not intended to serve as a replacement for a doctor or a doctor's advice, but could be a starting point for women to have a personal conversation with their physicians about their own choices.

"It's more about saying, 'Here's the data and let's perhaps put this kind of choice back in the realm of autonomy for women,'" she said. "Some women might look at this evidence and safety and say 'You know what, I like to have an occasional glass of wine.'"

Oster's deductions on alcohol consumption were also slammed by the U.S. National Organization on Fetal Alcohol Syndrome, which called her advice "deeply flawed and harmful."

"Emily Oster has no medical training or expertise and is unqualified to write a book which provides advice and guidance about alcohol use and pregnancy," the organization said in a statement.

The organization accuses Oster of cherry-picking studies and says that her statements will likely influence pregnant women to drink, thereby increasing the risk for their children of brain damage and Fetal Alcohol Syndrome.

"If Emily Oster wants to tolerate the risk of alcohol on her own baby, that’s her choice, but she has no right to advise pregnant women to expose their unborn baby to even a small amount of a substance that can cause brain damage."