Living near active oil and gas wells may put pregnant people at higher risk of having low-birth-weight babies, especially in rural areas, finds a new study of birth outcomes in California.
The study, funded by the California Air Resources Board, is one of the largest of its kind and the first in the state. It analyzed the records of nearly 3 million births to people living within 6.2 miles (10 km) of at least one oil or gas well between 2006 and 2015. Unlike previous studies, it examined births in both rural and urban areas and people living near both active and inactive oil and gas sites.
The study found that, in rural areas, pregnant people who lived within 0.62 miles (1 km) of the highest producing wells were 40% more likely to have low-birth-weight babies and 20% more likely to have babies who were small for their gestational age compared with people living farther away from wells or near inactive wells only. Among term births, babies were 1.3 oz (36 g) smaller, on average, than those of their counterparts.
People living near active wells in urban areas also had slightly increased odds of having small for gestational age babies than their counterparts. The study did not find a significant relationship between proximity to oil and gas wells and premature births.
“Being born of low birth weight or small for gestational age can affect the development of newborns and increase their risk of health problems in early childhood and even into adulthood,” said Rachel Morello-Frosch, a professor of public health and of environmental science, policy, and management at the University of California, Berkeley, and senior author of the paper. “When you see a shift of over 30 grams of birth weight among term infants, from an individual clinical perspective, it may not seem like a lot. But when you see that kind of large population shift in birth weight—that can have significant population level implications for infant and children’s health.”
The findings, published on 3 June in the journal Environmental Health Perspectives, add to a growing body of evidence linking proximity to oil and gas wells to a variety of adverse birth outcomes, including premature birth, heart defects, and low birth weight.
Oil production in California has generally declined over the past 3 decades, and Gov. Gavin Newsom last year issued stricter regulations on new hydraulic fracturing permits in the state. However, the state issued 24 new hydraulic fracturing permits in early April, and another 282 are awaiting review.
“This study is the first to characterize the implications for perinatal health of active oil and gas production in the state, and I think the results can inform decision-making in regulatory enforcement and permitting activities.” Morello-Frosch said. “Results from health studies such as ours support recent efforts to increase buffers between active well activities and where people live, go to school, and play. This scientific evidence of adverse health effects facing vulnerable populations, including pregnant women, should be taken into account as Californians debate the extent to which we to want to expand oil and gas drilling in our state.”