To Gain or Not to Gain
One of the more frequent questions I get from pregnant women concerns their weight. gaining weight throughout pregnancy. "Am I gaining too much weight," or "am I gaining too little weight for my baby?" "Why does my Facebook friend have a much bigger bump than I do at the same gestational age?" These obviously valid questions and concerns deserve to be addressed, so let’s take a brief look at weight gain during pregnancy. This is an important issue for many reasons. Studies show that excessive weight gain during pregnancy is more difficult to lose postpartum. In addition, excessive pregnancy weight puts infants at risk for increased birth weight. Emerging evidence indicates the occurrence of infant weight pre-programming in the womb. In other words, a woman who gains too much weight during pregnancy, or who is diabetic, is placing her child at increased risk of obesity and diabetes later in the child’s life. On the other side of the coin, women gaining inadequate weight produces risks of its own, such as infants with decreased birth weight. These concerns prompted several organizations to publish recommended guidelines for appropriate weight gain based on an individual’s pre-pregnancy weight. These guidelines are slightly altered to take into account women carrying twins. As always, if you have concerns about any of these issues please schedule an appointment to see your physician.
For women with a singleton the total gain during pregnancy is as follows: Prepregnancy BMI* Recommended Recommended Rates of Weight
Weight Category Total Weight (lb) Gain†in the Second and Third Trimesters (lb) (Mean Range [lb/wk])
Underweight < 18.5 28–40 1 (1–1.3)
Normal Weight 18.5–24.9 25–35 1 (0.8–1)
Overweight 25–29.9 15–25 0.6 (0.5–0.7)
Obese >30 11–20 0.5 (0.4–0.6)
For women carrying twins, the recommended weight gain is 37-45lb for normal weight women, 31-50lb for overweight women, and 25-42lb for obese women. Weight gain for twins is not determined for underweight women.
*Body mass index(BMI) is calculated as weight in kilograms divided by height in meters squared or as weight in pounds multiplied by 703 divided by height in inches. †Calculations assume a 1.1–4.4 lb weight gain in the first trimester.
Modified from Institute of Medicine Weight Gain During Pregnancy: Reexamining the Guidelines. https://www.ncbi.nlm.nih.gov/pubmed/20669500