Context: Soluble endoglin (sEng), a coreceptor for transforming growth factor with antiangiogenic properties, acts synergistically with sFlt1 to induce symptoms of HELLP syndrome in animal models and to promote a preeclamptic phenotype. Pregnant women with preeclampsia show increased sEng concentrations in circulation, whereas the sEng increase is detectable months before the clinical onset of the disease.

Objective: The aim of the study was to answer the question whether maternal sEng is altered in pregnancies with normotensive intrauterine growth restriction (IUGR).

Design: sEng and sFlt1 was retrospectively determined by a commercial ELISA.

Patients: The study includes 11 normotensive pregnancies with IUGR, 18 pregnancies with manifest preeclampsia and 15 gestational-age matched controls.

Results: Patients with preeclampsia showed significantly higher sEng concentrations compared to controls (57.0 ng/ml vs. 5.3 ng/ml, P < 0.001). Also IUGR pregnancies showed significantly elevated sEng concentrations (25.9 ng/ml, P < 0.001), but the levels were lower compared to the preeclamptic patients. There was a strong positive correlation between the sEng and sFlt1 concentration (Pearson 0.552, P < 0.01). Similar to sEng, the maternal sFlt1 concentration is highest in the preeclamptic patients (8388 vs. 2602 pg/ml, P < 0.01) but also significantly elevated in the IUGR patients (6952 pg/ml, P < 0.01).

Conclusions: Pregnancy with IUGR but without maternal symptoms are characterized by elevated sEng concentrations in circulation. Although this finding is less pronounced when compared to preeclampsia, sEng seems to be involved in different clinical manifestations of placental pathology.