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

OBJECTIVE: We evaluated the clinicopathological correlations of maternal serum free beta human chorionic gonadotropin (FBHCG)/ pregnancy-associated plasma protein A (PAPP-A) multiples of the median (MoM) ratio measured between 11+0 and 13+6 weeks of gestation, pregnancy characteristics and placental histopathology in pregnancies affected by fetal growth restriction (FGR). SUBJECT 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, avascular villi 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, 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 distal villous hypoplasia and avascular villi was described in cases with 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 a helpful marker as early as the end of the first trimester for identifying pregnancies that warrant close monitoring throughout gestation.