Customized birth-weight centiles and placenta-related fetal growth restriction

Area of Science:

• Obstetrics and Gynecology
• Perinatal Pathology
• Fetal Development

Background:

• Fetal growth restriction (FGR) diagnosis accuracy using customized vs. population-based birth-weight charts is debated.
• Previous studies often used non-specific proxies for FGR, potentially confounded by prematurity.

Purpose of the Study:

• To compare the diagnostic accuracy of customized versus population-based charts for identifying small-for-gestational age (SGA) infants associated with abnormal placental pathology.
• To assess the utility of customized charts in detecting specific types of placental pathology indicative of FGR.

Main Methods:

• Secondary analysis of a prospective cohort study in low-risk nulliparous women.
• Placentae underwent detailed histopathological examination.
• Small-for-gestational age (SGA) defined using customized (SGAcust) and population-based (SGAppop) charts; outcomes included maternal vascular malperfusion (MVM), chronic villitis, and fetal vascular malperfusion (FVM).

Main Results:

• SGAcust identified a higher proportion of infants with placental pathology (30.3% vs. 17.1%) and MVM (63.2% vs. 39.5%) compared to SGApop.
• SGAcust was associated with increased risk for chronic villitis and FVM, which SGApop was not.
• SGAcust demonstrated higher detection rates across various subgroups and for specific pathologies, with similar false-positive rates.

Conclusions:

• Customized birth-weight centiles appear superior to population-based centiles for detecting FGR associated with placental disease.
• This suggests customized charts offer improved diagnostic accuracy for FGR rooted in placental pathology.