Normal weight women gain 25-35 lbs during their pregnancies. Underweight women may need to gain more and overweight women less. For overweight women, dieting is safe and beneficial during pregnancy. Most weight gain comes in the second half of pregnancy and often women have gained no weight or even lost weight by 20 weeks; this is healthy. We check your weight at every visit, but don’t focus on how much you gain. We are usually not worried about you gaining too little weight but instead gaining too much. Excess weight gain increases the risks of pregnancy, including the risks of preeclampsia, diabetes, fetal macrosomia, and cesarean delivery.
Many overweight women will gain no weight for the entire pregnancy or even lose weight if they’re actively dieting. This is not a bad thing. Maternal weight gain when it is excessive is associated with excessive fetal size; but gaining too little weight during pregnancy will not make your baby too small if you are overweight at the start of the pregnancy.