News Review From Harvard Medical School -- Doctors Back Pregnancy Weight-Gain Limits
Doctors are urging overweight or obese women to gain less weight during pregnancy. The new guidelines come from the American College of Obstetricians and Gynecologists. These are the doctors who take care of most pregnant women. The guidelines say that overweight women should gain 15 to 25 pounds during the last 2 trimesters of pregnancy. Obese women should gain no more than 11 to 20 pounds. For women of normal weight, the doctors recommend a gain of 25 to 35 pounds. This should increase to 28 to 40 pounds for underweight women. The advice on weight gain is intended to lower risk to both the woman and the baby. Gaining too much weight during pregnancy can lead to gestational diabetes. This form of the disease disappears after childbirth. However, it increases the woman's risk of developing type 2 diabetes later. Excess weight also can increase the risk of cesarean section. Babies can grow to be very large, which increases their risk of obesity as children and in later life. But gaining too little weight can lead to babies being born too small and less healthy. The journal Obstetrics & Gynecology published the guidelines. HealthDay News wrote about them December 20.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
The more you weigh at the start of pregnancy, the fewer pounds you should gain during the final six months. That's the new advice from the American College of Obstetricians and Gynecologists (ACOG). Specifically, ACOG says:
- Obese women, with a body mass index (BMI) of 30 or more, should gain no more than 11 to 20 pounds.
- Overweight women, with a BMI between 25 and 29.9, should gain 15 to 20 pounds
Pregnant women starting at a normal weight should gain 25 to 35 pounds. A normal BMI is between 18.5 and 24.9. Underweight women need to gain more, 28 to 40 pounds.
This advice is very similar to what the Institute of Medicine recommended in 2009. It's reassuring to see this consistency in guidelines.
Some experts suggest that ACOG didn't go far enough. They say overweight and obese pregnant women should gain even fewer pounds. But ACOG was concerned that some women might make drastic dietary changes and not get enough vital nutrients. That's why the organization allowed more leeway for weight gain.
In fact, if an overweight or obese woman follows the ACOG guidelines, she would likely lose some body fat. Let's look at the numbers.
By the end of pregnancy:
- The baby weighs an average of 8 pounds
- Fluid around the baby (amniotic fluid) increases total body weight by 2 to 3 pounds
- Breast enlargement accounts for about 3 pounds
- The placenta weighs 1 to 2 pounds
- The uterus increases in size, adding 2 to 3 pounds
- Body fluid increases, about 6 pounds on average
That's a total of 22 to 25 pounds. On average, pregnant women put on an extra 5 to 8 pounds of fat.
But if an overweight or obese woman followed the guidelines and increased her body weight by only 20 pounds, she would actually lose 2 to 5 pounds of fat.
The advantages of minimizing weight gain for obese and overweight pregnant women include:
- A decreased chance of developing diabetes of pregnancy (gestational diabetes).
- A decreased risk of complications if a C-section is needed.
- A possible lower risk of developing preeclampsia. This pregnancy problem can be dangerous. It includes high blood pressure, excessive fluid buildup in the body and protein in the urine.
Research has shown that newborns are just as healthy if weight gain is kept in the recommended ranges. The babies are also less likely to be overweight. And there is some evidence of a lower risk of premature births.
What Changes Can I Make Now?
Ideally, it would be best for an overweight woman considering pregnancy to lose the weight before conception.
Once you become pregnant, you need to be even smarter about your diet. The first step to help minimize weight gain is to cut out all simple sugars. Start with sugary drinks and foods.
Keep meal portions small. One way to do this is to use small plates. Studies have shown that people like to finish whatever food is in front of them. With a small plate, you can't pile on the food.
Be sure you have a well-balanced diet with plenty of vegetables and some fruit. Low-fat cheese, lean meat and poultry, eggs and fish are good sources of protein. Avoid fish and other seafood that may contain higher levels of mercury. The ones to stay away from include swordfish, shark, king mackerel, tilefish, bluefish, lobster, saltwater bass and fresh tuna. Canned light or chunk light tuna is okay.
You will get hungry between meals. Choose healthy snacks, such as yogurt, a piece of fruit or unsweetened cereal. Drink low-fat regular or soy milk.
And take your prenatal vitamin every day. This provides insurance that you are getting the necessary vitamins and minerals, especially folic acid and iron.
What Can I Expect Looking to the Future?
We all know that maintaining a healthy weight improves quality of life and helps prevent many diseases. It's a bit surprising that we don't hear much about the importance of a healthy weight for mothers-to-be. For many women, this would be an added incentive to keep weight under control.