After the city of Flint, Michigan had its water source switched to a source that resulted in more toxic lead coming from people's taps, the birthrate dropped and the number of women suffering miscarriages rose by a "horrifyingly large" amount.

In 2014, Michigan officials switched the water source from the stable and relatively clean Great Lakes to the Flint River.  But the untreated river water leached lead from Flint's aging pipes.  Officials waited for months to tell the people, while lead levels exceeded the amount to be considered hazardous waste.  State officials are now facing criminal charges for their role.

Part of the impact on the people's health is now becoming clear.  Researchers from West Virginia University and the University of Kansas examined fertility and fetal mortality rates - they found that the birth rate,declined by 12 percent among Flint's women, while the fetal death rate increased by 58 percent.  And while that is described as "horrifyingly large", the authors of a new report (.pdf link) believe it's an undercount because it doesn't include miscarriages that happened before the 20th week of gestation, which is when most hospitals start counting.

"Overall, we found that approximately 275 fewer children were born in Flint than we would have expected had the city not changed its water source," said the report's co-author Dr. David Grossman in a statement. 

The babies born after Flint's lead crisis were slightly less healthy than average, but it's too early to know if they will suffer lead exposure's negative health impacts.  These include "decreased educational attainment, increased behavioral problems and criminal behavior, and worse labor-market outcomes," the authors write.