Very thin pregnant women at risk of severe nausea

More bad research.

"Women who are underweight when they become pregnant have an increased risk of severe, potentially dangerous nausea and vomiting, a large study suggests.

Many women suffer "morning sickness" in the early months of pregnancy, but in a small percentage of cases, the nausea and vomiting progress to a condition known as hyperemesis gravidarum. Women with this condition have unrelenting, excessive nausea and vomiting that puts them at risk of malnutrition, dehydration and significant weight loss.

Because of the risks to the mother and fetus, severe vomiting may require hospitalization and IV fluids."

How did this likely very small percentage of women become underweight?

Bulimia?

Conclusion?

"It's not clear why pre-pregnancy weight affects the risk of hyperemesis, Cedergren said. But she speculated that underweight women get a more severe form of the condition, more often necessitating hospitalization.

Another possibility, she and her colleagues note, is that doctors are quicker to hospitalize underweight women out of concern that they will rapidly become dehydrated and malnourished."

They don't know.

But they do know how to get a headline.