The major role of ultrasound in the first trimester of pregnancy is to establish the presence of a normal live intrauterine pregnancy and to distinguish this from either pregnancy failure or ectopic pregnancy. The most likely source of the CA-125 during pregnancy is the decidua and not fetal tissues or amnion. Vaginal bleeding in early pregnancy is associated with decidual destruction. Mechanical disruption of the decidua at the time of imminent abortion leads to the release of CA-125 into maternal blood. Progesterone is a C-21 steroid hormone, it has been regarded as the main pregnancy hormone balancing and inhibiting the stimulatory effect of estrogen until the last few weeks of pregnancy.