Over an 11-year period beginning in 1995, the proportions of babies born with a rare birth defect known as gastroschisis have doubled, according to a large study from the University of South Florida (USF).

The study examined "4,713 cases of gastroschisis occurring in 15 states during 1995-2005, using public use natality data sets for denominators," the report states. In women under the age of 20, 11.45 cases out of 10,000 resulted in gastroschisis, almost double women between 20-24 years old. "In the multivariable analysis, using non-Hispanic whites as the referent group, non-Hispanic black women had the lowest risk of having a gastroschisis-affected pregnancy."

While the defect has no known origin, young mothers are at a greater risk for giving birth to a baby with the defect.

What is gastroschisis?

Gastroschisis is manifested in newborns as an opening in the baby's abdomen, through which vital organs can protrude and spill out while still in the mother's womb. Doctors can use an ultrasound to discover cases of gastroschisis in the second trimester of a woman's pregnancy. Rates for the defect have risen from 2.3 cases out of every 10,000 live births in 1995 to 4.4 out of every 10,000 in 2005.

"We have a pattern where the prevalence is very much highest among young women and it's growing more rapidly among that group than any other group," said Russell Kirby, a professor at USF and the lead author of the study.

A lot of unknowns populate the study, unfortunately, namely the defect's rise in prominence and even details behind the defect itself. What scientists have pinned down is the increased risk across certain races and age brackets. Non-Hispanic white women under the age of 25, and especially 20, were the most likely to see the defect in their child. Women in their late 20s and 30s experienced no heightened risk for delivering a baby with the defect.

A mother's exposure to certain chemicals has also been tied to the malformation, though not conclusively.

But while the rates are rising, a separate study conducted in 2007 reports survival rates hover around 90 percent. Performed by researchers at the University of Texas at Dallas, the study found fetal gastroschisis cases between 1998 and 2006 occurred at a rate of 1 per 2,000 deliveries — or 66 cases. In many of the cases, delayed closure was necessary because the fetuses were underweight when born.

Treatment For Gastroschisis

Gastroschisis requires surgery no matter how otherwise healthy the baby is at the time of birth. Often, doctors will attempt to tuck the protruding organs back into the baby's abdomen, but recent advances have allowed them to treat the herniated organs by entombing them in a plastic "silo," which constricts the organs and gradually pushes them back inside. The doctors can then stitch the area closed. The silo method allows the infant's bowel function to return to normal without undue pressure on surrounding organs.

Kirby speculated that nutrition could possibly have something to do with the trend, but more research is needed to figure it out.

"We know that there are influences of different vitamins and nutrients that definitely affect fetal development," he said. But as far as their relation to gastroschisis, "that's just a suspicion."