Last June, in the Journal of the National Medical Association, I published the results of clinical trials that showed that it was safe for obese pregnant women who followed a well-balanced diet to gain little or no weight. Prior to my study, the conventional wisdom was that all women, even obese ones, should gain 26 to 35 pounds. That guidance had come from the most august body of ob-gyns in the U.S., The American College of Obstetricians and Gynecologists (ACOG), whose recommendations were based upon what we knew in the 1980s. That was before we fully understood the dangers of obesity in pregnancy. Yet, the guidelines had never been updated.

Being obese during pregnancy greatly increases the risks of preeclampsia, diabetes, stillbirth, and blood clots, among other problems. Gaining more weight if you’re already obese makes complications more likely while limiting weight gain makes them less so.

But until my study was published, obstetricians lacked the evidence that limiting weight gain among pregnant women was safe. The ACOG’s guidance from the 1980s stated that, unless a woman, obese or not, gained at least 26 pounds, the baby in her womb would be at risk of dying.

Right before my study results were published, a government body recommended that obese women gain somewhat less weight: between 11 and 20 pounds. It was a start but still not enough. And most board certified obstetricians would wait for the ACOG to – you’ll excuse the pun – weigh in before they changed their practices.

I’m delighted to say that, in a commentary in the peer-reviewed journal Obstetrics & Gynecology, the ACOG has just come out in favor of limiting weight gain among obese pregnant women. My study, which was quoted in the commentary, appears to have been instrumental in effecting this turnaround.

Now that the ACOG is changing its recommendations, obstetricians are more likely to change how they manage their patients. Fewer women will be told that it’s fine to gain weight during pregnancy if you’re already obese. And that will mean healthier moms and healthier babies.

I’m proud to have played a role in helping to make this happen.

– Yvonne S. Thornton, MD, MPH