Performance of the INTERGROWTH-21st and World Health Organization fetal growth charts for the detection of small-for-gestational age neonates in Latin America

Abstract

Objective: To evaluate the performance of INTERGROWTH-21^st (IG-21^st ) and World Health Organization (WHO) fetal growth charts to identify small-for-gestational-age (SGA) and fetal growth restriction (FGR) neonates, as well as their specific risks for adverse neonatal outcomes.

Methods: Multicenter cross-sectional study including 67 968 live births from 10 maternity units across four Latin American countries. According to each standard, neonates were classified as SGA and FGR (birth weight <10^th and less than third centiles, respectively). The relative risk (RR) and diagnostic performance for a low APGAR score and low ponderal index were calculated for each standard.

Results: WHO charts identified more neonates as SGA than IG-21^st (13.9% vs 7%, respectively). Neonates classified as having FGR by both standards had the highest RR for a low APGAR (RR, 5.57 [95% confidence interval (CI), 3.99-7.78]), followed by those who were SGA by both curves (RR, 3.27 [95% CI, 2.52-4.24]), while neonates with SGA identified by WHO alone did not have an additional risk (RR, 0.87 [95% CI, 0.55-1.39]). Furthermore, the diagnostic odds ratio for a low APGAR was higher when IG-21^st was used.

Conclusion: In a population from Latin America, the WHO charts seem to identify more SGA neonates, but the diagnostic performance of the IG-21^st charts for low APGAR score and low ponderal index is better.

Keywords: developing countries; fetal growth; fetal growth restriction; growth standard; low birthweight; perinatal morbidity; perinatal outcomes; pregnancy; small for gestational age.