(CNN) State officials are investigating to see whether lead-contaminated Flint River water had any effect on the rate of miscarriages in the city, said Jennifer Eisner, a spokeswoman for the Michigan Department of Health and Human Services.
Dr. Mona Hanna-Attisha, the Michigan doctor who warned authorities about high levels of lead and iron in the Flint's water, is leading a separate investigation, according to the Detroit Free Press.
So far, the state and Hanna-Attisha say it's too early to tell whether the Flint water caused an increase in miscarriages.
In fact, the state says nobody knows if miscarriages increased while women in Flint drank the contaminated water because statistics are not available yet.
The state's investigation is proactive and not based on citizen complaints.
"It's something that our epidemiologists are looking at, because we know lead can have effects throughout the life course," Eisner said.
The state gets yearly statistics on miscarriages and other subjects, she said.
"We have 2013 data up on our website," she said. "The 2014 data will be tested soon. We pulled the 2014-2015 data for our epidemiologists to take a look at."
The Centers for Disease Control and Prevention says there is "consistent evidence" that pregnant women exposed to high lead levels have a higher risk of "spontaneous abortion," or miscarriage, which is defined as the loss of a fetus before the 20th week of pregnancy.
High levels of lead can also cause physical and mental developmental problems in children, such as low birth weight.
Dr. Jeanne Conry, past president of the American Congress of Obstetricians and Gynecologists, said research of smelting workers with high levels of chemical exposure shows a clear association with miscarriages.
It's harder to analyze with people with low exposure, she told CNN, because of other variables, including diabetes and obesity, two conditions that are especially prevalent in impoverished cities such as Flint. Women who are healthy with a low lead-level exposure may have less risk of miscarriage.
Conry, who echoed the mantra that there is no safe level of lead, called for more research.
Hanna-Attisha plans to collect children's teeth over the next five years, the Free-Press reported.
"Teeth are like tree rings," she said. "You can see if the kid was lead-exposed, how much lead exposure there was, and when the kid had it. We're also looking at newborn heel spots (the blood taken in hospitals from the heels of all newborns) because lead in water impacts newborns. We're going to get lead levels from those heel spots."
Flint, an economically depressed city of about 100,000 people, became aware of high levels of lead in the drinking water last year.
About two years ago, the city started getting its water from the Flint River. It previously bought Lake Huron water through the city of Detroit. The state government made the switch to cut costs.
Soon after the change, the water started to look, smell and taste funny.
It was discovered the Flint River water had high levels of iron and contained lead from the connecting pipes. A local hospital discovered the percentage of Flint children with elevated lead levels nearly doubled after the switch, according to CNN affiliate WDIV-TV in Detroit.
The governor declared a state of emergency. The city switched water supplies but the damage was already done to the lead pipes. The state is now handing out filters and bottled water with the National Guard.
Meanwhile, Michigan Gov. Rick Snyder and Darnell Earley, Flint's former emergency manager, have been called to testify before the House Oversight and Government Reform Committee about Flint's water crisis, WDIV reported. The hearing will be held in March.
Snyder turned down an invitation to testify before Congress a few days ago, saying he had to deliver a budget presentation to the state Legislature that day.
Also on Friday, the city of Flint lifted a boil-water advisory issued after a February 9 water main break.
"Affected residents no longer need to boil their filtered water because testing did not reveal any bacteria during or after the repair of the water main break," the city said.