Season of conception a factor in how a child does in school

May 8 2007

According to the latest research the time of year a woman conceives may affect her child's academic performance.

In a study led by Dr. Paul Winchester of Indiana University School of Medicine, the researchers found that when they linked test scores to the month in which each student had been conceived, children who were conceived between June and August scored significantly lower on math and language tests than children conceived during other months of the year.

The 1,667,391 students in grades 3 through 10 had taken the Indiana Statewide Testing for Educational Progress (ISTEP) examination and the researchers say the correlation between test scores and conception season remained even when factors such as race, gender, and grade level were taken into account.

Dr. Winchester suggests a possible explanation may be that the pesticides used to control pests in fields and homes and the nitrates used to fertilize crops and gardens are at their highest level in the summer.

Environmental pesticides in turn influence nitrate levels in the surface water such as streams and ponds during that same time period.

Dr. Winchester says exposure to pesticides and nitrates can alter the hormonal balance of a pregnant woman which can affect the developing fetal brain.

This theory has the support of other research which has linked exposure to pesticides and nitrates to low thyroid hormone levels ("hypothyroidism") in pregnant women.

Maternal hypothyroidism and lower maternal thyroid in pregnancy is associated with lower cognitive scores in offspring.

Winchester says that while the current findings do not provide conclusive evidence that pesticides and nitrates contribute to lower test scores, they strongly support such a hypothesis.

Dr. Winchester, the director of Newborn Intensive Care Services at St. Francis Hospital in Indianapolis, says more research needs to be done on the issue.

The research was presented this week at the Pediatric Academic Societies' annual meeting.