Pregnant women living close to a high density of natural gas wells drilled with hydraulic fracturing were more likely to have babies with lower birth weights than women living farther from such wells, according to a University of Pittsburgh Graduate School of Public Health analysis of southwestern Pennsylvania birth records.

[Photo: Dr. Bruce Pitt]

The finding does not prove that the proximity to the wells caused the lower birth weights, but it is a concerning association that warrants further investigation, the researchers concluded. The study was funded by The Heinz Endowments and published in PLOS ONE.

“Our work is a first for our region and supports previous research linking unconventional gas development and adverse health outcomes,” said co-author Dr. Bruce Pitt, chair of Pitt Public Health’s department of environmental and occupational health. “These findings cannot be ignored. There is a clear need for studies in larger populations with better estimates of exposure and more in-depth medical records.”

Unconventional gas development includes horizontal drilling and high volume hydraulic fracturing, known as “fracking.” It allows access to large amounts of natural gas trapped in shale deposits. Prior to 2007, only 44 wells were known to be drilled in Pennsylvania’s Marcellus Shale with such technology. From 2007 to 2010, that expanded to 2,864 wells.

The Pitt Public Health research team cross-referenced birth outcomes for 15,451 babies born in Washington, Westmoreland, and Butler counties from 2007 through 2010 with the proximity of the mother’s home to wells drilled using unconventional gas development. They divided the data into four groups, depending on the number and proximity of wells within a 10-mile radius of the mothers’ homes.

Mothers whose homes fell in the top group for proximity to a high density of such wells were 34 percent more likely to have babies who were “small for gestational age” than mothers whose homes fell in the bottom 25 percent. Small for gestational age refers to babies whose birth weight ranks them below the smallest 10 percent when compared to their peers.

The researchers took into account many factors that could influence a newborn’s weight – including whether the mother smoked, her prenatal care, race, education, age, and whether she had previous babies, as well as the gender of the baby – and the finding still held.

Dr. Shaina L. Stacy, a recent graduate of Pitt Public Health, is lead author on this research, and Dr. Evelyn Talbott, epidemiology professor at the school, is senior author. Additional authors are Dr. LuAnn L. Brink, and Dr. Bernard D. Goldstein, both of Pitt Public Health; and Dr. Jacob C. Larkin, and Dr. Yoel Sadovsky, both of Magee-Womens Research Institute and Pitt School of Medicine.

For more information visit http://www.upmc.com/media/NewsReleases/2015/Pages/plos-one.aspx.