Living Near Fracking Sites During Pregnancy Tied to Poor Birth Outcomes

By Linda Carroll

April 06, 2022

NEW YORK (Reuters Health) - Babies born to women who lived near a hydraulic-fracturing site during pregnancy are at increased risk of being small for gestational age and having major congenital anomalies, a new study suggests.

The population-based retrospective cohort study also showed the risk of spontaneous preterm birth was heightened when mothers-to-be lived near many wells, researchers report in JAMA Pediatrics.

"If there was at least one well within 10 km - compared to no wells - there was an increased risk of small for gestational age (from 6.5% increased up to 7.3%) and major congenital anomalies (from 0.7% up to 0.9%)," said senior author Dr. Amy Metcalfe, an associate professor at the University of Calgary and director of the maternal and child health program at the Alberta Children's Hospital Research Institute in Calgary, Canada.

"These are statistically significant (risk increases), but when looking at absolute changes in risk, they're small," Dr. Metcalfe told Reuters Health by email. "However, we observed a much bigger increase in risk associated with living near high-density operations, that is, greater than 100 wells within 10 km compared to 1-24 wells within 10 km, with an increased risk of spontaneous preterm birth (from 4.5% up to 7.5%) and small for gestational age (from 8.0% to 12.6%). The changes observed with living near high-density versus low-density fracking are both statistically and clinically meaningful. So while there appears to be some degree of risk associated with living near any fracking operations, the main point to highlight is that living near high-density fracking operations seems to be what's driving these adverse outcomes."

To take a closer look at the potential impact of fracking on pregnancies, Dr. Metcalfe and her colleagues took a look back at data for all reproductive-aged women who were living in a rural area of Alberta, Canada, and had a pregnancy between 2013 and 2018.

The study included more than 26,000 women with some 34,000 pregnancies and a mean age of 28 years.

After accounting for factors such as parental age, multiple births, infant gender, obstetric comorbidities and area-level socioeconomic status, the relative risk of delivering a small-for-gestational-age baby was 1.12 and that of having a baby with major congenital abnormalities was 1.31 among women living within 10 km of one or more wells.

Compared with women living near 1-24 wells, those who lived in proximity of 100 or more wells had a 64% increased risk of having a spontaneous preterm birth after adjustment, and a 65% increased risk of having a baby that was small for gestational age.

It's not yet known exactly how proximity to the wells could be related to increases in adverse birth outcomes, Dr. Metcalfe said. "However, potential mechanisms would likely relate to air pollution or surface spills impacting the quality of ground water."

The new findings add to the growing body of evidence suggesting living near fracking sites may raise the risk of adverse birth outcomes, said Dr. Joan Casey, an assistant professor of environmental health sciences at Columbia University's Mailman School of Public Health in New York City.

"I would say there are now probably 10 studies that have found adverse birth outcomes linked to fracking," said Dr. Casey, who was not involved in the new research. "This is the first large-scale study to be done in Canada. The others have been done in Pennsylvania, Texas, Colorado and California."

No one knows yet how these well might be adversely impacting pregnancies, Dr. Casey said. "So many different exposures could be related to fracking, including air and water pollution," she added. "Other researchers have talked about psychosocial stress of this new industry moving into our community."

Dr. Casey pointed to a Harvard study that investigated a connection between fracking and all-cause mortality. That study, she said, found an increased risk associated with being downwind.

Until we can explain how the wells might be associated with adverse outcomes, it won't be possible to offer suggestions for how people can protect themselves, Dr. Casey said.

SOURCE: JAMA Pediatrics, online April 4, 2022.