The Waterloo Region District School Board is investigating after several staff members at one Waterloo school suffered miscarriages within three months.

Between late May and early August, four of the 38 staff members at Sandowne Public School suffered miscarriages.

“We have started an investigation, working with these individuals to find out some of the background and see if we can understand the situation better,” says Graham Shantz, the WRDSB’s assistant superintendent of human resource services.

Shantz says the school board considers it an “isolated incident” unless the investigation determines otherwise.

As part of that investigation, school board officials are talking to the four staff members, as well as consulting with school board and Region of Waterloo Public Health specialists.

Region of Waterloo Public Health officials contacted by CTV News would not comment on whether what happened to Sandowne staff members was a medical or statistical anomaly.

Medical experts say as many as 25 per cent of women may experience miscarriages before 20 weeks of pregnancy.

One issue being looked into is an insecticide that was sprayed on school property last in to help deal with an ant problem.

 “It is a product that is common across the province, but it is part of our investigation,” says Shantz.

The school board is looking into whether the product was applied at other schools.

Greg Weiler, president of the Elementary Teachers’ Federation of Ontario’s Waterloo Region branch, says the teachers’ union is watching the situation closely.

“We’re monitoring things right now and at whatever point it becomes clear that there is an appropriate action that needs to be taken or a concern that comes up from the school, then we’ll follow up on that,” he tells CTV News.

Shantz says it’s not clear how long the investigation will take.

“We don’t have a defined timeframe,” he says.

“As we continue to work forward, we’ll keep all people who need to know up-to-date on information.”

Parents of children at Sandowne Public School received a letter informing them of the situation Thursday afternoon.