Pregnancy

I'm a plus-size woman and I've actually lost 10 pounds or so during my first trimester without trying — is this normal? Is it safe for my baby?

It's not uncommon for overweight women to lose some weight during pregnancy or to have only a small weight gain during pregnancy. Sometimes women experience a temporary drop in weight in the first trimester, and the weight returns slowly over the next two trimesters. This shouldn't harm your baby as long as you're eating a nutritious diet.

Weight loss may occur for various reasons. Part of the weight gain during pregnancy is to provide you with energy reserves in the form of stored fat, which you'll need during labor and nursing. But if you already have enough reserves, your body may adjust accordingly. The larger you are at conception, the less weight you may gain. (Read more about how much weight to gain during pregnancy.)

Also, your body uses more calories during pregnancy, so if you don't change your diet, you'll probably end up losing some weight. During pregnancy, your body's priority is to provide your baby with nutrition, so as the calories you intake go toward his growth, your body may resort to using fat stores to keep you going — leading to weight loss.

Additionally, many women lose weight in their first trimester thanks to the nausea of morning sickness, which causes them to lose their appetite.

But don't worry too much about weight loss hurting your baby. Studies of women with severe nausea and vomiting in pregnancy have shown that babies do well despite maternal weight loss. A small 1998 study also showed that for obese pregnant women, weight loss or minimal weight gain during pregnancy didn't affect the pregnancy's outcome.

Do tell your healthcare provider right away about any sudden, dramatic change in your weight — losing or gaining 10 pounds in a week, for example — as it may indicate an underlying problem.

The best thing to do is eat a nutritious diet to provide the nutrients that your baby needs to grow and that you need to stay healthy, and don't let yourself go hungry.

Reviewed by Paula Bernstein, M.D.