March 18, 2005

Rise in dramatic intestinal birth defect probed

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Aungela Phillips and her son, Jacobe, have been dealing with the effects of gastroschisis.
photo by Dana Johnson

Rise in dramatic intestinal birth defect probed

Researchers at the Monroe Carell Jr. Children's Hospital at Vanderbilt say a nearly three fold increase in a rare birth defect called gastroschisis is raising questions about what is causing this dramatic defect.

Infants with gastroschisis are born with their intestines on the outside of their bodies.

Sonya Collins, M.D., a doctor with the Division of Neonatology and Preventive Medicine, says her instructors suspected rates of this birth defect were increasing in the state of Tennessee.

“For years, Drs. Mildred Stahlman and William Walsh had observed an increased number of babies referred to VCH with gastroschisis,” said Collins. “So we began a simple project inside the hospital to track the number of babies with the defect admitted to the intensive care nursery per year.”

Collins, under the guidance of her mentor, Marie Griffin, M.D., professor of Preventive Medicine, performed a review involving the birth certificate database and found a two-to-three fold increase in the number of babies born with gastroschisis in the state.

“It is very important to determine what is happening with this major birth defect,” Griffin said. “Several studies in multiple countries indicate that over the past 10 years, gastroschisis has doubled or tripled. The first step is to make sure the increase is real — not due to better reporting or other artifacts. Based on our review of the literature and the data Dr. Collins has gathered so far, we believe it is a real increase. The next question is why?”

“One theory is that very early in utero development something happens with the vascular supply to the abdominal wall that may lead to a decrease in blood flow to the developing area involved in the gastroschisis birth defect,” Collins said. Previous studies have come up with a few common associations. One strong risk factor appears to be the age of the mother.

“Mothers less than 20 years old appear to be at higher risk compared to an older mother,” Collins said. “It may be something a woman of young maternal age is exposed to more frequently than those of an older age or a combination of factors.”

When other studies have looked at what those mothers consumed, for example, they found an association with several things: vasoactive medications, including an over-the-counter cold medicine called phenylpropanalomine (that has been recently banned) and pseudoephedrine. Smoking, diet and economic status of the mother are also associated with an increased risk of developing the birth defect.

Eighteen-year-old Aungela Phillips' age certainly fits the profile. But the high school senior says she had a very healthy pregnancy.

“I was very active in dance,” said Phillips. “That may be why he was very healthy even though he was born four weeks early. He was bigger than they thought he would be at 5 pounds, 12 ounces.”

Her son, Jacobe, has a small gastroschisis defect. Doctors were able to tuck his intestines back into his belly just after birth and seal up the defect with a scar so small, it looks just like a part of his belly button.

While prenatal checkups found Jacobe's gastroschisis early and she had plenty of time to prepare, other families have far more to deal with. When too much of the intestines are outside the body, doctors sometimes use a protective sleeve to contain and protect the intestines. Gravity is then used to help the intestines settle back into the abdominal cavity by hanging the protective sleeve from a bar across the crib. If there is too much twisting and interruption of blood flow as the intestines settle back in, sections can die and the infants can become victims of short bowel syndrome (SBS), which can require a bowel transplant, or death due to lack of absorption of nutrients.

Now Collins and her team are reviewing the charts of 369 Tennessee babies born with gastroschisis or a similar defect called omphalocele. The team includes Collins, Griffin, William Cooper, M.D., associate professor of Pediatrics; Patrick Arbogast, Ph.D., assistant professor of Biostatistics; Margaret Rush, M.D., assistant professor of Neonatology; Brian Carter, M.D., associate professor of Neonatology; and William Walsh, M.D., professor of Neonatology and chief of neonatal intensive care.

They say they are finding nearly a three fold increase in the combined abdominal wall (gastroschisis and omphalocele) defect between 1985 and 2005. Collins said that in a future study they will also comb the prenatal charts of the mothers, looking for any factors associated with the defect. The abstract for the study was published in the Journal of Perinatology last September. Currently, the research is being reviewed for publication.

“Sonya's research will determine more precisely when the increase began and whether this increase was confined to particular locations in the state or specific age or risk factors,” said Griffin. “Answering these questions may provide clues to why this is happening, and hopefully lead to ways to prevent these rare, but very serious birth defects.”