Correlation between placental weight and angiogenic markers sFlt-1 and PlGF in women with preeclampsia and fetal growth restriction

Objectives: The angiogenic factors sFlt-1 (soluble fms-like tyrosine kinase) and PlGF (Placental Growth Factor) play a key role in the pathophysiology, prediction and diagnosis of preeclampsia-associated pregnancy disorders. However, the correlation between maternal serum levels and the placental weight, especially in hypertensive pregnancy disorders is still unclear. Study design: Retrospectively, we analyzed data from a real-world cohort of patients with preeclampsia (PE), intrauterine growth restriction (IUGR), PE + IUGR and controls giving birth within 14 days from inclusion. Herein, correlational analyses were calculated between placental weight, maternal serum levels of sFlt-1, PlGF and the respective sFlt-1/PlGF-ratios. Main outcome measures and results: This study included n = 328 patients (n = 134 with PE, n = 40 with IUGR and n = 25 showed PE + IUGR) and n = 129 controls. The gestational age-adjusted placental weight was significantly decreased in patients with PE +/- IUGR, but not in PE alone, when comparing to controls. Correlation between PlGF and the placental weight was significantly positive and increasing with severity of disease (controls 0.134, p = 0.131, PE 0.419, p < 0.01, IUGR 0.517, p < 0.01, PE + IUGR r = 0.723, p < 0.01). Furthermore, an inverse correlation between the sFlt-1/PlGF-ratio and the placental weight was found. The sFlt-1/PlGF-ratio per gram placental weight was highest in patients with PE + IUGR and lowest in controls (0.6 (IQR 0.4-1.8) vs. 0.05 (IQR 0.02-0.15)). Conclusion: A correlation between the serum levels of sFlt-1 and PlGF and the placental weight is present in PE associated pregnancy disorders. This mirrors the model of an angiogenic continuum in the placenta where the serum sFlt-1 to PlGF ratio increases with severity of the disease.