Clinical data supporting the importance of vascular LH/hCG receptors of uterine blood vessels

Recent studies revealed functional extragonadal gonadotropin receptors at s everal sites of the human body. The human chorionic gonadotropin/luteinizin g hormone (hCG/LH) receptor messenger RNA and protein were found in the end othelial and vascular smooth muscle layers of the human uterine arteries. I n vivo administration of hCG decreased the blood flow resistance in the hum an uterus and in vitro increased vasodilating eicosanoids in the vascular w all. These findings initiated a further study investigating whether the adm inistration of hCG to patients with signs of threatened abortion has any be neficial effect. The patients were treated with either magnesium or progest erone and/or hCG. The results showed that the rate of patients reaching sec ond trimester was higher when hCG was included in the treatment protocol, a nd a parallel significant decrease in uterine blood flow resistance was als o found. Analyzing the long-term results, the rate of preterm and growth-re tarded deliveries was lower when hCG was administered in the first trimeste r. As a conclusion, the uterine vascular LH/hCG receptors play a significan t role in the peri-implantation period. The hCG might also participate in a ngiogenesis, enhancing long-term clinical results.