As a family physician, I had the honor and unmitigated privilege of attending the birth of over 1500 babies in my career. Each one was a special experience for me. And, as you can imagine, mothers-to-be always had tons of questions about pregnancy and their newborn-to-be. Of course, the issue of weight gain was always on the list. This is of great importance to many mothers-to-be, because the health of the newborn depends a lot on the mom’s weight. And now, for the first time in nearly two decades, officials at the Institute of Medicine (IOM) have issued new guidelines regarding weight gain during pregnancy. 
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Given the current epidemic of overweight and obesity in young people, including mothers-to-be, the new guidelines could not have come along at a better time. Especially since “excessive weight gain during pregnancy has short-term and long-term adverse effects, such as a greater risk of having a C-section and retaining those extra pounds for the mother,” USA Today reported.   
There is also an increased risk “of being born prematurely or large with extra fat for the baby. Women who are overweight to begin with also have a greater risk of developing pregnancy-related high blood pressure and diabetes.” 
These are problems that may be hard to avoid, considering that “half of all pregnancies are unplanned, so many women weigh too much when they conceive.”
According to a story in the Los Angeles Times, “more than 60 percent of US women of childbearing age are overweight or obese – a significant increase from 20 years ago.” 
Figures like those, alongside pregnancy complications and the “growing rates of obesity in children,” put “pressure on the” IOM “to revise a set of 1990 guidelines that were written primarily to prevent excessively low infant birth weights.” 
But, “with few exceptions, such as putting a limit on how much weight obese women should gain, the new guidelines are the old guidelines wrapped up in a lecture.”
For the majority of women, Time reported, “including those who are underweight, normal weight, or even overweight at conception,” the unchanged guidelines still suggest that:
 

• “women with a healthy body mass index, or BMI … of 18 to 25 are advised to gain 25 to 35 pounds during pregnancy,” while 
• “overweight women with a BMI of 25 to 29.5 should gain less, up to 25 pounds; 
• underweight women, with BMIs below 18.5, should gain more, up to 40 pounds.”

 
In regards to obese women, HealthDay noted that “obese moms-to-be should limit their weight gain during pregnancy to between 11 and 20 pounds,” whereas the 1990 guidelines “recommended that obese mothers-to-be gain at least 15 pounds during pregnancy.” 
The IOM committee is also urging clinicians to “provide diet and exercise counseling to women before conception so that women can achieve a normal BMI before becoming pregnant.”
Michael Katz, MD, senior vice president for research at the March of Dimes, a co-sponsor of the study, “said the aims of the report are laudable, but ‘the effects are very difficult to achieve'” through a “concerted effort,” MedPage Today reported. “While Dr. Katz said the new guidelines are more conservative than those past, others say they are not conservative enough.” 
Nonetheless, the report’s authors are calling “for further study of pregnancy in obese women, as well as the impacts of gestational weight gain on maternal and child outcomes.”