Early delivery of low-birth-weight infants linked to poor school outcomes

Infants with severe small for gestational age who were delivered iatrogenically due to suspected fetal growth restriction, or FGR, had poorer developmental and neurocognitive outcomes than infants without suspected FGR, data show.

Researchers found no association between iatrogenic delivery and poorer outcomes among infants with normal growth who were suspected of having FGR vs. those without suspected FGR.

“The timely delivery of the growth-restricted fetus is not a simple decision,” Roshan John Selvaratnam, BMedSc, of the department of obstetrics and gynecology at Monash University in Australia, and colleagues wrote in JAMA. “When compounded by the risks of neurocognitive and intellectual impairment associated with FGR alone, the attending clinician faces a challenging dilemma: either intervene early to prevent a small risk of stillbirth but potentially cause immediate and lifelong harm to the child, or accept the increasing risk of stillbirth associated with prolonging the pregnancy to avoid more common neonatal and longer-term morbidities.”

Selvaratnam and colleagues conducted a retrospective, population-based cohort study using birth data from the Victorian Perinatal Data Collection, which were then linked to developmental and educational outcomes from the Australian Early Development Census and the Australian National Assessment Program — Literacy and Numeracy. The dataset included all live singleton births at 32 weeks’ or more gestation in Victoria, Australia, between Jan. 1, 2003, and Dec. 31, 2013. The participants were followed until grade 7 or 2019.

The analysis included 705,937 infants with a mean gestational age of 39.1 weeks and a mean birth weight of about 7.6 lbs. Among them, 181,902 infants had available information on developmental results and 425,717 had information on educational results.

Compared with infants with severe small for gestational age (SGA) who were not suspected of having FGR, those with severe SGA who were delivered for suspected FGR were born earlier (mean gestation, 37.9 weeks vs. 39.4 weeks) and had a significantly increased risk for poor developmental outcomes at school entry (16.2% vs. 12.7%; adjusted OR [aOR] = 1.36; 95%CI, 1.07-1.74), as well as poor educational outcomes in grade 3 (10.5% vs. 7.9%; aOR = 1.28; 95% CI, 1.06-1.55), grade 5 (12.3% vs. 9.7%; aOR =1.25; 95% CI, 1.02-1.54) and grade 7 (13.4% vs. 10.5%; aOR = 1.33; 95% CI, 1.04-1.7).

There was no significant difference between infants with normal growth who were delivered iatrogenically due to suspected FGR and those without suspected FGR in developmental outcomes (8.6% vs. 8.1%) or educational outcomes, despite being born earlier (mean gestation, 38 vs 39.1 weeks), according to Selvaratnam and colleagues.

“The primary goal of detecting the growth-restricted fetus is to reduce their stillbirth risk via timely delivery. The challenge is that it has been shown that early delivery in the setting of FGR comes at the cost of increased neonatal morbidity related to iatrogenic prematurity,” Selvaratnam and colleagues 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.”

In a related editorial, Robert M. Silver, MD, and Nathan R. Blue, MD, professors in the maternal-fetal medicine division at the University of Utah, said that the findings should be considered as “hypothesis generating” due to potential confounding, the lack of a consistent FGR definition and inaccurate assessments of SGA.

“In many pregnancies, gestational dating is uncertain, limiting the ability to accurately assess size or weight for gestational age. Although estimated fetal weight is a reasonably good approximation, it is prone to error, especially for fetuses measuring on the extremes of ‘normal’ fetal size,” Silver and Blue wrote. “Taken together, SGA status in the fetus or neonate correlates with adverse outcomes statistically but is a relatively poor discriminator of adverse outcomes.”

The added that the study underscores the “critical” need to assess the longer-term outcomes of obstetric interventions and to develop a standard definition of FGR that is "based on more than fetal/neonatal size and perinatal compromise.”

“Such a standard definition would need to be defined by biological evidence of abnormal placental function and corresponding fetal adaptation and be able to capture the wide range of clinical severity with which FGR presents,” they wrote. “In addition, critical outcomes that may not be apparent through 6 weeks after delivery but that may ultimately drive improvements in care should be assessed. Only then can diagnostic, management and interventional approaches to the complex problem FGR presents be investigated.”

References:

• Selvaratnam RJ, et al. JAMA. 2021;doi:10.1001/jama.2021.8608.
• Silver RM, Blue NR. JAMA. 2021;doi:10.1001/jama.2021.8381.