Obesity in Pregnancy

It’s no secret that obesity is common, and the prevalence continues to increase over time. In the last few decades the number of overweight and obese women in the United States who have become pregnant has grown substantially. Over one-half of women are overweight in pregnancy and just as many gain too much weight during pregnancy. As a result, many risks are increased, including early pregnancy loss, gestational diabetes, blood pressure complications, fetal growth restriction and birth defects.

So what is recommended to keep both an expectant mom and her baby safe and healthy?

Knowing your BMI to start is very important. This is based on height and pre-pregnancy weight and can be calculated with easy-to-use online tools, such as that found at the Centers for Disease Control and Prevention’s (CDC) website (www.cdc.gov). Normal weight is defined as a BMI of 18.5 to 24.9, overweight 25 to 29.9 and obese > 30.

Many obese women have difficulty with conception due to abnormal menstrual cycles, endocrine disturbances such as polycystic ovarian syndrome and increased risk of early miscarriage. Weight loss and consultation with your healthcare provider and, sometimes, reproductive or endocrine specialists can be beneficial when having difficulty establishing pregnancy.

Once successfully pregnant, women with obesity should meet with their healthcare provider to discuss weight gain and nutrition during pregnancy. Normal-weight women are expected to gain 25 to 35 pounds during a healthy pregnancy, about one pound per week in the second and third trimesters. On the contrary, the recommendation for overweight women is to gain much less: 15 to 25 pounds if overweight, 11 to 20 pounds if obese and generally about 0.5 pounds per week in the second and third trimesters.

Sticking to these weight-gain guidelines has been shown to improve outcomes for the expectant mom and baby alike. This can generally be accomplished with a healthy diet, nutritional counseling in some cases and a safe exercise regimen. In the first trimester your provider may also want to get some baseline blood work, including diabetes testing, kidney function tests and others as indicated. If you’ve had bariatric surgery, your provider or nutritionist will assess for nutritional deficiencies and determine if additional supplements are needed.

In the second trimester you’ll want to have a thorough anatomy ultrasound as the rate of some congenital anomalies is slightly increased for babies of obese women. The risk of birth defects overall remains low, however. Glucose testing will be done (or repeated if it was done in the first trimester) around 24 to 28 weeks. If gestational diabetes is diagnosed, it can often be treated with dietary changes alone. However, some women will require insulin or other medications to lower blood glucose. You will want to continue to stick your weight-gain guidelines and modest exercise regimen.

In the third trimester you will see your provider more frequently to monitor your blood pressure, screen for protein in your urine and ensure that your baby continues to grow adequately. You will want to be sure your little one is moving every day, and your provider can instruct you on kick counts or how to monitor fetal movement. Some women will need additional fetal testing or ultrasounds as the due date approaches.

For some women with obesity, labor can be a slower process than for normal-weight women; however, the pushing time is the same and most women with an otherwise uncomplicated pregnancy still go on to have a normal vaginal delivery. Breastfeeding is still encouraged for all women as a way to improve the health of mom and baby in the long term, as well as for a quicker return to pre-pregnancy weight.

With healthy living habits and close attention to guidelines specific to women with obesity, rest assured that you can still have a healthy pregnancy and delivery.

Margaret K. Chory, MD, is a general obstetrician/gynecologist practicing in Pittsburgh, PA.