Pregnancy is a time of important health and nutrition choices to support the growth and development of your new baby. While it may be tempting to use pregnancy as an excuse to eat whatever you want, continuing to follow a well-balanced diet will help prevent an unhealthy weight increase. Weight gain is a natural and expected part of pregnancy, but how much weight to gain varies from person to person. While body mass index, or BMI, is not always an accurate indicator of body weight because it can be skewed based on muscle mass, it is generally an acceptable guide in determining how much weight should be gained during pregnancy. A physician or registered dietitian can suggest a recommended weight gain for your specific needs and can offer tips and advice about how to do so healthfully.
Normal Pre-Pregnancy Body Weight
For women with a normal pre-pregnancy weight, usually with a BMI of 18.5 to 25, weight gain should total between 25 and 35 lbs. over the course of nine months. This weight gain should be slow during the first trimester with only about 1 lb. gained each month. Some women may even experience some weight loss during the first trimester if nagging nausea and morning sickness affect their appetite. During the second and third trimesters, a good rule of thumb for healthy weight gain is about a pound a week.
Overweight and Obese Pre-Pregnancy
For women who start their pregnancies already overweight with a BMI between 25 and 29, a weight gain goal may be between 15 to 25 lbs., with about 1 or 2 lbs. gained in the first trimester and a half pound gained weekly thereafter. If your BMI is greater than 29, weight gain goals may be even lower. Talk with your doctor about how much weight you should gain, but generally you will only need to gain between 11 and 20 pounds. Although achieving and maintaining a healthy weight throughout life is important, pregnancy is not a time to start dieting or trying to lose weight.
Underweight Pre-Pregnancy
For women who start their pregnancy underweight, their total weight gain goals are higher than the average woman. In addition to gaining about 1 lb. per month during the first trimester, an underweight woman should try to gain about 1 to 2 lbs. weekly in the second and third trimesters for a total weight gain of about 28 to 40 lbs.
Carrying Multiples
For many reasons, being pregnant with multiples requires higher weight gain to support the growth of more than one baby. For twins, a woman of healthy weight pre-pregnancy should gain about 37 to 54 lbs. Overweight women at the beginning of their pregnancies should aim for a slightly lower weight gain with goals around 30 to 50 lbs.
