Kids who get too early a start at life – even if they are born in the first half of the gestation period associated with "normal term" birth – appear more likely to struggle at reading and math by the time they reach third grade, new research suggests.
In a study published Monday in the journal Pediatrics, researchers aimed to find out whether there were differences in third grade reading and math scores among nearly 130,000 children considered to have been born within a "normal" gestational range between 37 and 41 weeks.
What they found was that those born at 37 weeks and 38 weeks had significantly lower reading scores compared to children born at 39, 40 or 41 weeks. Math scores were also lower for children born at 37 or 38 weeks.
Lead study author Dr. Kimberly Noble, assistant professor of pediatrics at Columbia University Medical Center and New York-Presbyterian Hospital, said the findings should give parents-to-be pause before opting for early birth for non-medical reasons.
"The evidence from this study would suggest that elective induction of birth should be approached cautiously," Noble said. "The data suggest that children born at 37 or 38 weeks may have problems with reduced school achievement later on."
Noble said that even after taking a number of other factors into account – among them birth weight, socioeconomic background and maternal education – the link between earlier birth and academic performance was still evident. She added that, while it was possible that some other unmeasured factor could be responsible for the connection, "until we have more data we would encourage parents and physicians to exercise caution when considering elective induction of birth prior to 39 weeks gestation."
The study is the latest addition to a growing body of evidence that purely elective induction of birth may be a bad idea. According to statistics from the U.S. Centers for Disease Control and Prevention, such births appear to be a growing trend. Only 9.5 percent of all births in 1990 were through elective induction. Compare that to 2007, which saw nearly 23 percent of all births electively induced.
Efforts by many hospitals to encourage full-term pregnancies appear to have blunted this trend in recent years.
"The thing to keep in mind is that a child born 36 weeks, 6 days has brain size two-thirds that of a term infant," said Dr. Bryan Williams, associate professor of family and preventative medicine at Emory University School of Medicine in Atlanta. "They're still at a deficit with regard to brain development."
Williams and his colleagues have done their own research in which they compared the academic performance of more than 300,000 children in Georgia to their pre-term or post-term birth status.
"We found similar results, and arguably even greater relationships between test failure and gestational age," he said. "We, in fact, found kids at lower gestational age, who were extremely premature, were 250 percent more likely to fail a math test."