Wrangling with Diet, Exercise, and Weight Gain in Pregnancy

It would be hard to find a sharper contrast of scientific views. On one hand, weight gain during pregnancy “is not modifiable via diet and lifestyle change,” write Jodie Dodd and colleagues. But then again, Helena Teede and colleagues found “level 1 evidence” that diet and physical activity interventions help with less excessive weight gain in pregnancy and fewer adverse outcomes.

How can two smart groups of researchers reach such starkly wildly different conclusions?

Listening to Different Views

These two groups published their papers within months of each other. The paper by Teede et al is a systematic review and meta-analysis that went online in JAMA Internal Medicine on December 20. The Dodd Paper came out just about two weeks ago. But they each seem to be looking at different research. Could this be a subtle case of confirmation bias?

Dodd et al point to a study of their own as definitive support for their conclusions. Theirs is the largest study of lifestyle and dietary intervention in pregnant women to date. What’s more, another large trial confirms their findings, they tell us. Case closed. They write:

“Gestational weight gain is not modifiable via diet and lifestyle change, and continued efforts to find the ‘right’ intervention for women with overweight and obesity during pregnancy are unjustified.”

Yet Teede et al come to the opposite conclusion:

“Antenatal structured diet and physical activity–based lifestyle interventions were associated with reduced GWG and lower risk of adverse maternal and neonatal outcomes. The findings support the implementation of such interventions in routine antenatal care and policy around the world.”

While Dodd et al seem to rely heavily on their own research, we note that Teede makes no reference to that research at all. Perhaps these folks are not listening to each other.

A Subject That Requires Listening

It’s hard to imagine a subject that requires listening more than weight gain in pregnancy for women already living with obesity. Apparently, that doesn’t happen enough. Frankie Fair and colleagues report in PLOS One that women with a high BMI get a lot of repetitive finger wagging about the risks of excessive weight, but not a lot of practical advice. They conclude:

“Services centred on individual women’s needs and on their current and previous experiences are required.”

And guess what? That requires listening with respect. A good practice for us all in quite a wide range of situations.

Click here for the Dodd paper, here for the Teede paper, and here for the Fair paper. For excellent perspective on the evidence base and gaps in it, click here.

Mother, painting by Joaquín Sorolla / WikiArt

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July 5, 2022