Many of the rules and prohibitions surrounding pregnancy have been heard by women dozens of times before even hearing them from their doctors for the first time.
A new book from University of Chicago economist Emily Oster finds that many aren’t based in statistics or reality, like prohibitions on caffeine and alcohol.
Oster loved coffee and wine and was curious if she could drink them while pregnant, but got vague, unsupported, and occasionally contradictory advice from her doctors. One or two glasses of wine were “probably fine,” and coffee was to be avoided, or to be kept under 2 cups a day.
In an article in The Wall Street Journal, Oster describes what happened when she took a serious economist’s look at the studies doctors have been citing to justify blanket prohibitions for years, and applied decision theory to her own pregnancy.
The conclusions? “Drink like a European adult, not like a fraternity brother,” and don’t be afraid of a cup, or even multiple cups of coffee.
- Heavy drinking is obviously an issue, but Oster found that there was “no credible evidence” that having a glass of wine a day during the second and third trimesters would have any cognitive impact on a child, and a recent study supports her. There’s scant or no evidence that light drinking has a negative effect on behaviour or IQ either.
- In one of the most highly cited studies finding a connection between light drinking and behavioural problems, 45% of the women who reported having one drink a day reported using cocaine during pregnancy, versus 18% who abstained totally.
- Researchers have asserted that coffee might cause miscarriages or impede development. Coffee is rough on the stomach and triggers nausea for many in pregnancy’s early stages. Nausea is a sign of a healthy pregnancy, and those able to drink coffee early and abundantly may have other issues.
- Studies that account for nausea find little issue with moderate coffee consumption. One highly cited study did find higher miscarriage rates for heavier coffee consumers, but found no effect for women who reduced consumption during pregnancy. The nausea factor seems like the most likely explanation for that behaviour.
The common thread is that the studies don’t really decouple correlation from causation.
Oster found enough evidence that she personally felt comfortable with a glass of wine now and then, and continuing to drink three to four cups of coffee a day when she felt up to it. Her 2-year-old daughter is perfectly healthy.
In the book, she also addresses the advice women get about their weight (worry more about gaining too little than too much), physical activity, and what they eat (sushi is fine, raw milk cheese isn’t) .
Women are hugely invested in having a healthy pregnancy and child, so are often inclined to err on the side of safety. A lot of current advice seems to make them unnecessarily miserable, uncertain, or guilty, and isn’t much help in making an informed, correct decision.
The book, “Expecting Better: Why the Conventional Pregnancy Wisdom Is Wrong-and What You Really Need to Know,” will be released on August 20th.
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