A staggering statistic - at least one in 20 pregnant women suffers from an eating disorder.
Some are calling it "pregorexia," and it's dangerous for both mom and baby.
We met an Oklahoma woman who has been through three pregnancies all while battling a demon that won't go away.
"It's a daily battle," said Jennifer Lewis. "So it's not something you can just stop."
She looks like an average mom of three healthy kids. But Lewis carries around a secret struggle that threatened those young lives.
"I started eating and I would vomit every once in awhile," she said. "Then it became every other day, to daily, to five or six times a day."
Her bulimia began ten years ago after she lost 100 pounds. When Lewis got pregnant with her first child, she was able to stop purging at first.
"I went from binging and purging every day to keeping all my food down, so I gained a tremendous amount of weight. And even though I told the doctors and nurses that I had an eating disorder, they would tell me you're gaining too much weight. Slow down. Just stop," she said. "So then it threw me in a downward spiral, where there was no getting back up from that."
Dr. Meghan Scears specializes in treating eating disorders, and has seen her share of pregnant patients.
"Part of it is they lack perspective. "They're not able to fully see the other things that are going on," she said. "The things that others can easily see, they struggle to see."
You're much more likely to develop an eating disorder while pregnant if you've struggled in the past. And the risks are serious.
"It increases chances of stillbirth, miscarriage, of low birth weight babies, of respiratory distress upon birth," said Dr. Scears. "It increases the risk that the baby themselves will have an eating disorder."
There's also an increased risk of post-partum depression, which Lewis experienced.
More awareness of eating disorders during pregnancy comes as it gets its own name, pregorexia.
"Pregorexia is a new term for me, although I do believe it's a real condition," said Integris Canadian Valley OB-GYN Joseph Mitro.
Dr. Mitro says most women should gain 25-to-35 pounds while pregnant. Women who start out overweight should gain less. Underweight women should gain more.
Dr. Mitro watches his patients' weight gain carefully, knowing many keep their struggles a secret.
"Most women who have an eating disorder before getting pregnant are not going to be inclined to share those problems when they get pregnant," he said.
Lack of weight gain can be easily disguised as morning sickness. It was an excuse Lewis often used after throwing up.
"I would be in bathrooms or I'd be here and there, and I'd come out and say, 'Oh, morning sickness.' Because you're embarrassed by it. You're ashamed of it," she said.
That shame has transformed into a passion to get more women to seek help and to raise understanding. She realizes some people will hear her story and wonder how she could knowingly put her unborn children in danger.
"One most important thing that people need to realize is it's not controllable," she said. "It's not something you can control. It is a mental illness."
If you are pregnant and suffering from an eating disorder, the best thing you can do is tell your OB, who can send you to work with a nutritionist to make sure you're getting enough of the right foods for you and your baby.
We take a look at extreme diets while pregnant in the 2nd part of this series. One expectant mom is getting a lot of attention for her pregnancy diet. It includes eating 20 bananas a day.