Approximately 1 percent of babies born in the United States are conceived through in vitro fertilization (IVF). IVF is generally considered safe, but several studies have identified short-term health risks, including neurological problems in children conceived by IVF, warranting longer follow-up studies. A recent study in Human Reproduction examined cognitive function in children conceived by IVF and found these children to consistently outperform their naturally-conceived peers on standardized tests.
The study contacted Iowa families with IVF-conceived children who were currently eight to 17 years old. Parents were mailed questionnaires about their kids’ educational development. They were asked if their child had skipped or been held back a grade, received remedial or advanced education, or been given a diagnosis of attention deficit or autism. Parents were also asked about their own highest level of completed education. Of 497 couples contacted, 295 couples with 463 children agreed to participate in the study. The majority of parents were white, college educated, and still married.
Using the results of the Iowa Tests of Basic Skills (grades 3 to 8) and Educational Development (grades 9 to 12), the study compared the scores of children conceived by IVF to those of a group of naturally conceived children matched by grade, year, gender, and school district. Both tests’ scores included subtest scores for reading, math, language, and a composite of the three, or core total. Scores were also obtained for vocabulary, which is found to strongly correlate with IQ.
The study found that IVF kids outperformed their matched peers on all subtests and across all grades. Among IVF children, the study also found several statistically significant associations among parent/child factors and test scores:
- Higher education levels of parents result in higher reading and vocabulary scores
- Older age of mother results in higher reading, math, language, core total, and vocabulary scores
- Lower current body mass index (BMI) of child results in higher language and core total scores
- Having divorced parents results in lower total scores overall
While the study benefited from the validity provided by a large sample size and objective measure of cognitive ability, there is always more to the findings than numbers alone. Researchers suggest that more privileged socioeconomic status and higher levels of parental involvement among IVF families could account, in part, for these kids’ higher test scores. The study findings are certainly reassuring, however, in suggesting that IVF does not have a negative effect on cognitive development. Looks like they don’t call them test tube babies for nothing!