A new study in the wake of the Flint, Michigan, water contamination crisis uncovered unsettling trends in fertility rates and fetal deaths during the time period the city was grappling with high levels of lead in its water supply. The working paper by West Virginia University's Daniel Grossman and University of Kansas' David Slusky concluded that "between 198 and 276 more children would have been born had Flint not enacted the switch in water."

Fetal deaths, when pregnancies last longer than 20 weeks but don't result in a live birth, rose 58 percent from April 2014 to 2016. Fertility rates dropped by 12 percent during that time period. "Either Flint residents were unable to conceive children, or women were having more miscarriages during this time," Slusky said.

The timing of these shifts is notable, as it was in 2014 when Flint's water was contaminated with dangerous levels of lead after the local government, under a state-appointed emergency manager, changed the city's water sources. The Centers for Disease Control and Prevention say that lead "can damage a developing baby's nervous system, causing miscarriages and stillbirths, as well as infertility in both men and women," USA Today reported.

The Michigan Department of Health and Human Services, however, concluded in July 2015 that there was no "evidence that indicates the water switch" affected fetal death rates. Becca Stanek