Morphological and structural changes of umbilical veins and clinical significance in preeclampsia

Preeclampsia is a common complication of pregnancy that is characterized by high blood pressure. Preeclampsia can have both negative maternal and fetal effects, including impaired fetal development from reduced placental perfusion. Because umbilical vessels provide fetal blood supply, morphological changes in these vessels can critically affect fetal function. This study investigated morphological and structural changes in umbilical veins from 17 controls and 19 preeclampsia cases.

36 umbilical cords were collected, and take umbilical cord of placental, middle, and fetal segment to H&E and orange G staining. Microscope images were obtained by digital microscope, and wall thickness, lumen diameter, wall-luminal ratio and tunica media thickness, Area of smooth muscle, area of nuclei, nuclei density, and nuclear area density of smooth muscle in tunica media were tested by Image-pro Plus.

Lumen diameter of umbilical veins gradually decreased, while wall thickness, tunica media thickness, and wall-luminal ratio gradually increased, from placental to fetal segments of umbilical veins. Area of smooth muscle, area of nuclei, nuclei density, and nuclear area density did not significantly differ from placental to fetal segments of umbilical veins. Compared to controls, (1) Preeclampsia cases had a smaller lumen diameter and greater wall thickness, tunica media thickness, wall-luminal ratio; (2) Preeclampsia cases had higher nuclei density and nuclear area density, and had no difference in area of smooth muscle and area of nuclei. In fetal segments of umbilical veins from preeclampsia cases, correlation analysis showed that wall-luminal ratio negatively correlated with gestation age, birth weight, and Apgar score.

These results indicate that umbilical vein of preeclampsia cases has a thickened tunica media from smooth muscle proliferation, which may be an adapted reaction to hypertension. Altogether, this study demonstrates that morphological changes in umbilical veins adversely affect fetal development in preeclampsia cases.