Low-Weight Babies Delivered Early Do Worse in School

Among babies who were severely small for gestational age, early induction of labor was associated with worse developmental and educational outcomes later on in childhood, according to results from an Australian retrospective study.

Infants who were severely small for gestational age (SGA) and who were iatrogenically delivered for suspected fetal growth restriction (FGR) had an increased risk of poor developmental outcomes at school entry compared to those who were not delivered early (aOR 1.36, 95% 1.07-1.74), reported Roshan John Selvaratnam, BMedSc, of Monash University in Melbourne and colleagues.

Small for gestational age infants delivered early for suspected fetal growth restriction also had worse educational outcomes at grades 3, 5, and 7, the researchers wrote in JAMA.

Among babies with a normal birth weight, however, the researchers observed no differences in childhood development and educational outcomes between those who were delivered iatrogenically for suspected fetal growth restriction and those who were not.

While the primary goal of iatrogenic delivery for suspected fetal growth restriction is to reduce stillbirth risk, the challenge is that clinicians must balance the risk of stillbirth with that of developmental outcomes and morbidities associated with prematurity, Selvaratnam’s group wrote.

“The findings in this study add to that challenge because infants with severe SGA correctly iatrogenically delivered for suspected FGR had poorer developmental outcomes at school entry and poorer educational outcomes compared with infants with the same degree of growth restriction, but who were not suspected of having FGR,” the authors stated.

In an accompanying editorial, Robert Silver, MD, and Nathan Blue, MD, both of the University of Utah in Salt Lake City, said that this study highlights a further need to evaluate the long-term outcomes associated with obstetric interventions for small for gestational age and fetal growth restriction. But they added that before we can truly investigate long-term outcomes, “foundational” knowledge gaps — such as how we define normal growth — must be addressed.

“Before screening and diagnostic approaches can be optimized, before predictive models for FGR-associated morbidity can be developed, and especially before testing the effect of interventions such as delivery timing, the nature of normal and abnormal fetal growth must be understood,” Silver and Blue wrote. “A standard definition is needed based on more than fetal/neonatal size and perinatal compromise.”

In this study, Selvaratnam and colleagues linked perinatal data from a birth database in Victoria, Australia to government data sources of developmental outcomes and school test scores. They included all singleton births that occurred at 32 weeks’ gestation or more from January 2003 to December 2013. The group followed children up until they reached grade 7, or until 2019. Stillbirths and neonatal deaths were excluded from the analysis.

Small for gestational age was defined as a birth weight below the 10th percentile, and severe SGA was defined as a birthweight below the third percentile. Infants were classified as iatrogenically delivered for suspected fetal growth restriction if they were delivered either by induction of labor or pre-labor cesarean delivery, and if the FGR diagnostic code was listed as the indication for delivery.

The researchers controlled for potential confounders including infant sex, hospital type, maternal age, socioeconomic status, maternal Indigenous status, and maternal region of birth.

Selvaratnam’s team analyzed nearly 706,000 live births. They linked around 180,000 children to early developmental outcomes data, and more than 425,000 to national school test score data. All births occurred at an average of 39 weeks’ gestation, and had a mean birthweight of 3,426 grams.

Infants with severe SGA and suspected FGR were delivered earlier on average compared to infants with SGA who did not have suspected FGR (37.9 vs 39.4 weeks, respectively).

Babies with severe SGA who were delivered iatrogenically were more likely to have poor developmental outcomes when they started school, compared to those who were not delivered early (16.2% vs 12.7%, respectively).

Additionally, these children had worse developmental outcomes at grades 3, 5, and 7. As childhood age increased, the gap in educational outcomes decreased, but it was never eliminated entirely.

Despite being born earlier, infants with a normal birthweight who were delivered iatrogenically for suspected fetal growth restriction did not have significantly worse developmental outcomes (aOR 1.17, 95% CI 0.95-1.45), or school performance at grades 3, 5, or 7.

Selvaratnam and colleagues recognized that no causal associations can be inferred from these results, which may be limited by confounders such as smoking during pregnancy, maternal BMI, and breastfeeding status. Additionally, they did not have detailed information on fetal biometry, Doppler studies, or other markers of pathology that may have helped differentiate babies who were physiologically small from those who were pathologically small.