"The weight of evidence didn't support limiting my consumption very much," wrote Oster in an article in The Wall Street Journal last week.
"I decided to continue drinking my three to four cups a day."
On alcohol, Oster had been told by her doctor that one or two glasses of wine a week was "probably fine".
"But probably fine isn't a number," she writes in Expecting Better.
"In search of real answers, I combed through hundreds of studies... to get to the good data.
"This is where another part of my training as an economist came in: I knew enough to read the numbers correctly. What I found was surprising."
Among the studies looked at by Oster was one that appeared in the journal Pediatrics which had concluded that just one drink a day was enough to put unborn children at risk of behavioural problems.
But as reported by The Times, the research didn't reflect that 18 per cent of the women didn't drink at all, and 45 per cent of those who enjoyed a drink every day also took cocaine.
"Perhaps the problem is that cocaine, not the occasional glass of chardonnay, makes your child more likely to have behaviour problems," concluded Oster, who now believes that women should be able to have one or two drinks a week during the first trimester and one a day during the second and third without worrying about damage to their baby.
Responding to her claims, a spokesman for the Department of Health, which recommends severely limiting alcohol consumption, said:
"Drinking during pregnancy can be associated with miscarriage, fetal alcohol syndrome and low birth weight.
"Our advice remains that women who are trying to conceive or are pregnant should avoid alcohol. If women choose to drink, to minimise the risk to the baby, they should not drink more than one to two units of alcohol once or twice a week and should not get drunk."
Other potentially harmful foods and substances investigated by Oster include sushi, soft cheese and cat litter.
While most were found to be far less harmful than supposed, one activity that did turn out to be problematic was gardening, thanks to the risk of exposure to the toxoplasmosis parasite that lives in the soil.
Although some parenting experts have greeted the book with derision, Netmums founder, Siobhan Freegard, was cautiously welcoming of the findings.
"Advice on what to eat in pregnancy changes over the decades and even differs between cultures," she said.
"In years gone by women were even encouraged to drink alcohol in the form of stout as it was regarded as good for pregnancy.
"Our common sense tells us that Emily is probably right and the odd glass of wine won't do any harm but no one knows for sure so expectant mums will want to err on the side of caution until scientists can prove the safety of foods we are currently advised against eating.
"Official guidelines may seem stringent but they are there to err on the side of absolute safety. However nature is also very wise and many expectant mums find they suddenly develop a very strong aversion to the smell and taste of coffee and alcohol while pregnant, especially during the vital first trimester."
- DAILY MAIL
