A study published earlier this week claims that singleton babies born at 37 and 38 weeks may not do as well in school. As you can imagine, the study got quite a lot of attention.
Dr. Kimberly Noble, the lead author of the study and a pediatrician and developmental cognitive neuroscientist in Columbia University’s Department of Pediatrics and G.H. Sergievsky Center, took the time to talk with Kveller.
You recently published an article in the Journal Pediatrics that’s getting a lot of attention. Can you summarize the findings for us?
In this study we were able to link two databases, one from the New York City Department of Health (which keeps birth records with detailed info) and another from the Department of Education (a database with third grade reading and math test scores). What we found is that within full term range, which is defined as 37-41 weeks, babies born at later gestational stages performed better on reading and math tests.
What prompted this study?
We know from hundreds of studies that children born preterm, prior to 37 weeks, are at increased risk of developmental and academic difficulties. However, very little is known about any differences among children born within the full term range of 37 to 41 weeks. Brain development is ongoing during the last month of gestation, and so it is somewhat surprising that this hasn’t been looked at.
In the abstract of the article, you and your fellow researchers state that “achievement scores for children born at 37 and 38 weeks [were] significantly lower than those for children born at 39, 40, or 41 weeks.” What were the degrees of difference here? Were they very significant?
The differences were small but significant. Children at 37 weeks performed about a point below children at 41 weeks. This would not be noticeable from one child to the next, but it is important on a population or public health level, because it means that children in the early term range are more likely to have reading or math disabilities. For example, children born at 37 weeks are 33% more likely to have a severe reading disability and are 19% more likely to have a moderate math disability, relative to 41 weekers. Again, most children will perform normally, but there is an increased risk at earlier gestational age within the term range.
What do you think will be the practical implications of this study?
I think the most important implications come in the realm of early elective deliveries. Until we have further data, we urge parents and clinicians to exercise caution in scheduling elective deliveries for logistical regions (vacation, scheduling preference) in the “early term” range, prior to 39 weeks. Of course, if there is a medical indication for scheduling an early delivery, that is very different, and we recommend that women discuss this with their clinicians.
What might you say to those parents who have had children born at 37 or 38 weeks and might be concerned about these results? (Or to parents who already know that their child will be delivered prematurely)?
The differences that we found in average scores were small–only about a point on standardized tests. It is true that, at the lower end of the scale, children in the early term range have a somewhat increased risk of reading and/or math difficulties. However, increased risk is not the same as inevitability. Most children within the early term range of 37 or 38 weeks will perform normally. To the extent that early term birth confers risk, this may be used by pediatricians to identify children who may benefit from extra services.
I happen to know that you recently gave birth to a healthy baby girl—Mazal Tov! How did the results of this study–and what you know about neurocognitive development in general-affect you during your pregnancy? Did you find yourself thinking a lot about prematurity or did you just turn it off?
Thank you! I would say that what affected me more was having seen extremely preterm births during my training in the neonatal intensive care unit (at Columbia). In fact, during my own pregnancy, once I reached 37 weeks I was pretty relieved!
What’s it been like to be a pediatrician/mom, so far? Do you find that you reference your clinical and research knowledge as you watch the way your daughter makes eye contact or holds her head up? Or have you been able to just enjoy the burps and gurgles, unqualified?
I would say it’s a mixed blessing. There are definitely things I’ve worried about that I know I don’t need to, and it’s easy to wonder if every little thing is an indicator of some rare condition. I’m definitely glad to have a pediatrician (that’s not me!) who cares for my daughter, and even when I’ve known the answer to certain questions, I’ve tried hard to play mom instead of doctor to her.
Final question: if you could give a new parent just one piece of advice regarding child development, what would it be?
The most important ways parents can promote healthy child development are through early exposure to a cognitively stimulating and emotionally warm environment. Parenting is critical, and its effects far outweigh the small effects we see of gestational age within the term range.
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