Recent research revealed that residents near oil and gas wells might have increased risks of spontaneous preterm birth or the termination of pregnancy before 37 weeks of gestation. 

The study is population-based research that aimed to study how environmental factors may affect pregnancy. It was published in Environmental Epidemiology on June 5. 

The proximity of residences to oil and gas wells and spontaneous preterm birth in California focused on in this research. 

The lead author of the study, David Gonzalez of Stanford University's School of Earth, Energy & Environmental Sciences (Stanford Earth), noted that oil and gas exposure receive minimal attention in California despite having 2.1 million Californians and 17 million U.S. residents within one mile of active oil or gas wells. 

Researchers studied 225,000 cases of births from mothers who are residing within six miles of oil and gas wells in San Joaquin Valley for 13 years. Women with multiple births and pre-eclampsia were excluded from the study subject. 

Research areas were limited to wells with most emissions: oil wells that are preproduction stage or are under construction. There were about 83,000 wells, but only 12,000 of which are in preproduction. The study considered mothers living within six miles of these wells were considered of higher risk of exposure.

Higher Risks of Spontaneous Preterm Risks 

The study results were alarming: 8 to 14 percent of women living near the wells were found to experience spontaneous preterm birth at 20 to 31 weeks. From the 225,000 births studied for the past 13-years, 28,000 were spontaneous preterm births. It also revealed that women who were Hispanic, Black, or had fewer than 12 years of education were the most vulnerable to living near the oil wells. 

Spontaneous preterm birth is also the leading cause of death in infants in the United States. 

The researchers noted that the environmental contaminants and stressors that the residents are most exposed to were drinking contaminated water, stress from drilling noise, or breathing higher levels of polluted air around the wells. The researcher hopes to investigate further why spontaneous preterm birth is associated with living near the wells.

"We don't understand what causes preterm birth, but we understand that certain factors increase your risk, and environmental exposures are among those factors," Gonzalez says.

More Studies on Proximity of the  Oil and Gas Well to Sensitive Sites 

A previous study on residents living near oil and gas development establishments reported increased risks of low birth weight and early gestational age, but not preterm birth. Researchers noted that the previous study did not look closely into preterm birth, which this study focused on. 

According to Marshall Burke, a co-author and an associate professor in the earth system science department, as California is developing a regulation on how close to sensitive sites like schools, should oil and gas facilities operate. These studies should be carefully be considered in making such policies.  

The next crucial step is to study the distance of facilities to the well for it to cause harm, Burke added.