FLINT, MI - Flint's lead-in-water contamination crisis caused lower fertility rates and higher infant death rates, a new study says.

David Slusky and Daniel Grossman - two economics professors from the University of Kansas - released their findings from a working paper on Wednesday, Sept. 20, after analyzing data and comparing Flint birth and death certificates with those issued in other Michigan cities in a several-year time period before Flint changed water sources and after its use of contaminated water in April 2014.

According to Slusky and Grossman's analysis, after Flint switched its water source from Detroit to Flint River water in 2014, the city's fertility rates decreased by 12 percent among Flint women, while fetal death rates rose by 58 percent.

The overall health of Flint children at birth decreased as well, compared with children from other Michigan cities, the study reported.

"This represents a couple hundred fewer children born that otherwise would have been," Slusky said.

The economists' study looked to chart the potential causes of lead in Flint, as the effects of lead in the water on fertility and birth outcomes have not been well-established, Slusky said in the study.

Children born in the wake of Flint's use of lead-contaminated water were also affected, the study said. Researchers found a five percent decline in the average birth weight of Flint babies during the time the city was using contaminated water, compared with other Michigan children after accounting for potential selection of effects where lead caused the mother with the smallest fetuses to miscarry or have stillbirths.

The researchers also analyzed Flint's Google search data, to find when residents began searching lead and lead poisoning-related terms, which could indicate concerns about the effects of the lead in the water and could possibly influence potential parents' decision to having children, the study said.

However, results showed that residents did not begin searches on lead poisoning until research on the lead in Flint's water came to light in September 2015.

Less sexual activity was also not reported during the time period, meaning that "either Flint residents were unable to conceive children, or women were having more miscarriages during this time," Slusky said.

The information from the University of Kansas seemingly contradicts information in a draft report developed by the Michigan Department of Health and Human Services in July 2015, concluding that there is no "evidence that indicates the water switch" in Flint caused higher fetal death rates and other negative birth outcomes in the city.

A spokesperson for the DHHS was not immediately available for comment on the University of Kansas study.

Flint has a history of high infant mortality rates, nearly double the rate of the state as a whole from 2011 until 2015, according to Genesee County Health Department statistics.

Health professionals, including Dr. Mona Hanna-Attisha, have raised questions about whether the elevated level of lead in Flint's drinking water after the city's water source changed in April 2014 may have caused those rates to rise even further.

The city's water source was changed to the Flint River for 17 months in a cost-saving move while Flint was being run by emergency financial managers appointed by Gov. Rick Snyder.

The water source was changed back to the Great Lakes Water Authority in October 2015 after local, state and federal officials said improperly treated river water had damaged lead service lines and home plumbing, causing the toxin to leach into drinking water.

The Center for Disease Control says too much lead in a pregnant woman's body puts her at risk of miscarriage as well as increasing the risk of babies being born too early or too small.

The agency says lead can also damage a baby's nervous system and affect behavior and intelligence because lead can cross the placental barrier, exposing both mother and unborn child.

In January 2016, pregnant women and children under age six in Flint were advised by local, state and federal officials to stop using even filtered tap water unless it had been tested for lead.

In February 2016, both DHHS and Hanna-Attisha said they were separately examining any potential link between fetal deaths and Flint water.

Hanna-Attisha previously told MLive that her work in that area is incomplete. An MDHHS spokesperson previously said that the state's study examined six years of birth data for Flint.

Marc Edwards, the Virginia Tech professor who helped reveal rising levels of lead in water in Flint, published a study late in 2013 that linked stillbirth rates in Washington, D.C., with rising levels of lead in the water there.

Edwards has expressed doubt about being able to establish a similar connection here because the pool of affected residents was much larger in Washington and because lead levels there were about five times higher than Flint, the professor has said.

Fetal death means the death of a fetus that has completed at least 20 weeks of gestation or weighs at least 400 grams, including stillbirths, according to state law.

In addition to fetal deaths, DHHS tracks and requires reports on infant mortality, pre-term births and low birth rates -- all factors that could be a part of the agency's study.