I’ve managed to get two papers out over the past two months on obesity and pregnancy with my wonderful co-author, Susan Averett. One is available online at Maternal and Child Health Journal; the other is forthcoming in an edited volume, Applied Demography and Public Health. The basic gist of both papers is that maternal obesity is probably not as bad for kids as we tend to think. Using maternal fixed effects we show that kids of moms who were obese pre-pregnancy are not doomed to have worse outcomes than their siblings who were born to the same mothers but when they weren’t obese. There just aren’t that many differences in terms of adverse birth outcomes or obesity in early childhood.
One thing we can’t control for, that I’ve been discussing with a friend recently, is how gut bacteria plays a role in all this. This friend* is pregnant, very close to her due date, and, as she approaches her due date, has been religiously eating dates, largely based on the results of one study in Jordan that women who ate dates were more likely to go into spontaneous labor, labored for fewer hours, had higher mean cervical dilation, etc.
My immediate response was, “well, how can we be sure the women eating dates were different somehow than those who weren’t?” And my next move was to find the paper and point out this line:
As date fruit consumption is a part of the cultural beliefs of the population under study, it was difficult to get patients who would commit to not taking date fruit at all (control group), therefore the study group had more patients than the control group.
The authors are actually careful to say that the study should be repeated using a randomized control trial, but I don’t know that we learned that much from this as the control group is clearly different in this obvious way from the intervention group (they’re willing to give up dates). It is interesting, though, to think about how foods change our gut bacteria and how that might affect other health issues.
*Addendum: This friend would like to point out that she likes dates and was aware of the limitations of the study. “It can’t hurt!” she says.