Spontaneous abortion is the most common complication of pregnancy and responsible for significant emotional distress to couples desiring children. Approximately 70% of human conceptions fail to achieve viability and an estimated 50% are lost before the first missed period (Edmond et al., 1982). More than 80 percent of abortions occur in the first 12 weeks of pregnancy, and the rate decreases rapidly thereafter (Harlap et al., 1980). Most of these pregnancy losses are unrecognized. Recent studies using sensitive assays for the the beta subunit of human chorionic gonadotropins (β-HCG) indicated that the actual pregnancy loss after implantation is 31% ( Wilcox et al., 1988). The aim of this work was to study the transvaginal color Doppler of the uterine artery in combination with serum CA-125 and beta-HCG levels in first trimesteric threatened abortion patients.