Some believe that when a parent gives birth to a preterm infant, the clinical course of that infant can be so complex that it dissuades a family from wanting to have another child for fear a similar course may ensue. Yet how true is this? Alenius et al. (10.1542/peds.2017-1354) share with us the results of their study on this topic that begins with the knowledge that parents of extremely low birth-weight babies do have fewer subsequent children. What about less extreme degrees of prematurity? The authors use a large national cohort of infants from Finland and look at the effect of gestational age on the birth of a subsequent sibling. Interestingly enough, the authors found a correlation between gestational age and a decline in subsequent offspring that correlated with the earliest gestational age groups having the least number of offspring but an effect still being shown up to 36 weeks gestation. In fact, the number of subsequent “missing siblings” was far greater than the number of preterm infants who died at a particular gestational age.
What does this mean for our role as pediatricians and child health care professionals? We asked Northwestern University obstetricians and gynecologists Drs. Ashish Premkumar and William Grobman to weigh in with a commentary that reminds us that the Alenius study cannot prove causality (10.1542/peds.2017-3260). The commentary authors reframe the findings in terms of confounders that may not be recognized in this study and yet be more responsible for the findings of “missing siblings” than preterm gestational age will be. No matter what the cause, the association noted by Alenius is a most interesting one that will require more prospective study before we attribute premature births to lower rate of subsequent offspring birth. Have you seen this association in your practice? Any thoughts as to why it might be occurring? Share your thoughts with us by responding to this blog, adding a comment alongside the article on our website or posting your reflections on our Twitter or Facebook pages.