A Utah-led study published in the online British Medical Journal found women who had both infections one month before getting pregnant or during their pregnancy had a four times greater risk of their babies being born with gastroschisis, compared to uninfected women.

Gastroschisis happens when the developing baby's abdominal wall fails to fully develop, leaving the intestines to develop in the amniotic fluid. It can be found during an ultrasound, but surgery to repair it cannot be performed until after a baby is born.

About 25 babies are born with the defect each year in Utah, where it is more prevalent than in the rest of the country. Worldwide, the problem is much more common among mothers under 20, the same age group at most risk for STDs, which can cause urinary tract infections.

Researchers interviewed mothers in 10 states, including Utah, whose children had the defect and asked whether they had a variety of illnesses before or during their pregnancies. While lead author Marcia Feldkamp, director of the Utah Birth Defect Network, can't say how many women with STDs and urinary tract infections will have children with the defect, the study did find an elevated risk.

Feldkamp said Friday it's unclear why those infections would cause the defect. Doctors also can't say when or how the defect develops, meaning it may be too late to prevent gastroschisis during pregnancy. However, both infections should be treated during pregnancy to avoid other complications.

"Where we really have to intervene is before conception - making sure women know there may be a risk for a birth defect if they have an [STD] and a urinary tract infection," said Feldkamp, who expects to see gastroschisis numbers continue to jump in Utah since teen pregnancy and STD rates are up.