- Associated Press - Friday, May 2, 2014

DENVER (AP) - A study of birth defects detected in fetuses in Garfield County found no common underlying cause for the problems, the state health department announced Friday.

The investigation looked at 22 rare anomalies detected by ultrasounds at two clinics in Glenwood Springs in late 2013. Epidemiologists looked at more than a dozen factors, including where the babies were conceived, drinking water sources, smoking and alcohol use and proximity to active oil and gas wells.

Some had suspected that the defects could be the result of oil and natural gas drilling in the county.

The study found that 70 percent of the mothers lived more than 15 miles away from the nearest active drilling well and 30 percent lived between 5 and 8 miles from a well. None lived in the same neighborhood. The mothers, who ranged in age from 20 to 37, includes some from cites outside the county, including Meeker and Snowmass.

None of the water samples tested contained elevated levels of disinfection by-products containing trihalomethane, the study found. The powerful carcinogen can be a byproduct of oil and gas drilling but can also be found in agricultural fertilizers, Colorado’s chief medical officer, Larry Wolk, said.

“While some may have expected the investigation would identify one or two risk factors that link these cases, no such link was found,” he said in a statement. “It is natural to look at even a single birth anomaly and ask why. But sadly, birth anomalies do occur.”

Various anomalies were reported, including heart and chromosomal problems as well as two cases of molar pregnancies, which occurs when either an abnormal growth, rather than a fetus, or an unviable fetus, develops in the uterus.

The state mainly tracks birth defects in babies once they are born, including stillbirths, but not when they are still in the womb. Because of that, the study noted that there’s no way to know whether the number of anomalies reported in Garfield County are higher than normal.