Why Am I Losing Weight While Pregnant?

Weight loss during pregnancy may be unnerving for new moms who know how important extra pounds can be in order to keep baby healthy and happy. But here's why can you lose weight while you're pregnant and why it's perfectly safe.

Mother-to-be holds her pregnant belly.
Photo: George Rudy/Shutterstock

You expect the numbers on the scale to start creeping higher after you learn you're pregnant, so it's natural to worry if they're not. But losing weight in early pregnancy is actually pretty normal, especially if you've got a bad case of morning sickness. Here's what to know about weight loss throughout your pregnancy if it should happen:

Weight Loss in the First Trimester

As many as 80 percent of moms-to-be experience some form of pregnancy nausea, which can make keeping even the blandest food down a real challenge — resulting in some looser-fitting jeans these days. Be assured that losing a few pounds at this stage has no impact on your baby's development. And to put things in perspective, you're not supposed to be gaining that much weight yet anyway! Normal-weight women shouldn't gain more than two to four pounds — total — in the entire first trimester. By week 14 or so, your morning sickness should subside and your appetite will likely return with a vengeance. At this point, the majority of women who lost weight early on quickly regain it — and then some.

The only time weight loss is a problem is if it becomes significant, like more than 10 percent of your overall body weight — a 150-pound woman dropping to less than 135 pounds, for example. If this happens, your doctor will likely prescribe medication to ease your morning sickness so you can eat again and start gaining weight healthfully.

Weight Loss Through Week 40

No need for a new maternity wardrobe? Don't worry. Plus-size women may not gain as much weight during pregnancy as normal-weight or underweight moms-to-be — and this is totally fine and should have no impact on your baby's development. We've seen larger women gain as little just five pounds, or in some cases, even lose weight, while they're expecting. Here's why:

During pregnancy, very little of the weight you gain goes to the actual growth of your baby. Most is used to build up fat stores so you have energy for the challenges that lie ahead (i.e., childbirth and nursing). If you already have enough stored, you won't pack on as many pounds as women who need to gain more.

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