Not only did the water crisis in Flint, Michigan, cause illness in many of the city’s children due to lead exposure, it also had a severe, negative impact on pregnancies.

According to an article published yesterday in The Washington Post, a new working paper argues that a decline in fertility rates during the time the city drew its water from the Flint River was driven by an increase in fetal deaths and miscarriages. Per The Post:

The paper estimates that among the babies conceived from November 2013 through March 2015, “between 198 and 276 more children would have been born had Flint not enacted the switch in water,” write health economists Daniel Grossman of West Virginia University and David Slusky of Kansas University.

Flint’s water crisis was prompted by an April 2014 decision by the city to switch Flint’s water source from the Great Lakes Water Authority, which also provides water to Detroit, to the Flint River. Although residents immediately alerted city officials that the water had an odor, they were assured it was safe for more than one year.

In 2015, pediatrician Dr. Mona Hanna-Attisha tested blood lead levels in her young patients and, as previously reported by Colorlines, “Her research found that many of Flint children’s blood lead levels had doubled, and even tripled in some cases, after the city switched its drinking water source.” Her findings—though initially discredited—helped bring global attention to the crisis.

While the effects of lead exposure on children’s health have been extensively documented, less is known about how it impacts fetal health. In their study, Grossman and Slusky compared birth and fetal death rates in Flint with those in other Michigan cities from the time when the water source switched. Per The Post:

What they found was “a substantial decrease in fertility rates in Flint for births conceived around October 2013, which persisted through the end of 2015. Flint switched its water source in April 2014, meaning these births would have been exposed to this new water for a substantial period in utero (i.e., at least one trimester).”

During this time period, residents in Flint were generally unaware of the amount of lead in their water. “Because the higher lead content of the new water supply was unknown at the time, this decrease in [the general fertility rate] is likely a reflection of an increase in fetal deaths and miscarriages and not a behavior change in sexual behavior related to conception like contraceptive use,” Grossman and Slusky conclude.

While the city switched its water source back to Lake Huron in October 2015, residents of the majority-Black city are still dealing with the effects of the crisis. This includes a continued need to use water filters in their homes and the threat of property liens against people who stopped paying water bills for lead-poisoned water. These problems are exacerbated by the fact that, according to Census data released last week, Flint is the poorest city in the United States.