Correlations of Free Beta-Human Chorionic Gonadotropin/Pregnancy-Associated Plasma Protein A Ratio, Pregnancy Characteristics, and Placental Pathology in Fetal Growth Restriction.

Abstract

Objective: We evaluated the clinicopathological correlations of maternal serum free beta-human chorionic gonadotropin (FBHCG)/pregnancy-associated plasma protein A (PAPP-A) multiple of the median ratio measured between 11 + 0 and 13 + 6 weeks of gestation, pregnancy characteristics, and placental histopathology in pregnancies affected by fetal growth restriction (FGR).

Subjects and methods: We investigated 69 pregnancies complicated with FGR. Different indicators of FGR, placental villous capillarization, placental weight to birth weight ratio, and placental histopathological entities were correlated with FBHCG/PAPP-A ratio.

Results: Complication of FGR with preeclampsia (p < 0.001) and birth weight below the 2nd percentile (p < 0.001) were significantly more common when the FBHCG/PAPP-A ratio was higher. Placental weight to birth weight ratio was significantly lower (<1:8) in cases of higher FBHCG/PAPP-A ratio. Distal villous hypoplasia (DVH), avascular villi (AV), and chorangiosis were more prevalent in cases with a higher FBHCG/PAPP-A ratio; however, villous capillarization, onset of FGR, oligohydramnios, and preterm birth did not have an association with it.

Conclusion: In FGR, a higher FBHCG/PAPP-A ratio could be an early indicator of placental villous underdevelopment, which is further supported by the fact that higher prevalence of DVH and AV was described in cases with a higher FBHCG/PAPP-A ratio. We conclude that this ratio could be an early marker of potential placental dysfunction (and consecutive FGR later in pregnancy), rendering it a helpful marker as early as the end of the first trimester for identifying pregnancies that warrant close monitoring throughout gestation.

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