A new study conducted on the students in Indiana suggested that the season in which a child was conceived could affect its future academic achievement. Children that were conceived from June to August scored lower than other kids on math and language tests.

The hypothesis is that mothers' and in turn fetuses' exposure to the high pesticides used during summer months may play a significant role, a cause-and-effect that has yet to be proven.

The team of researchers studied more than 1.5 million Indiana students from grades 3 to 10 who took the Indiana Statewide Testing for Educational Progress (ISTEP) exam. They compared the test scores with the month in which each student had been conceived. The results showed a correlation between the ISTEP scores for math and language and the season of conception where the children conceived in months June to August had the lowest scores.

During the summer months, there is a stark jump in pesticides’ levels, such as atrazine, and fertilizer chemicals, such as nitrates found in streams and other waters. Past studies showed that pregnant women exposed to pesticides were more likely to develop hypothyroidism. Women who suffered from hypothyroidism while carrying a child were more prone to having children with cognitive performance issues.

Thyroid hormones are crucial to how well the brain functions, and while their brains are developing, the babies depend on their mothers’ thyroid gland.

The study results may not apply to the whole nation because they studied only the children from Indiana. More research is needed on higher level to confirm Indiana results.