Relationship between serum CA 125 levels, endometrial thickness and corpus luteum function in different stages of ovarian activity

CA 125 is a cell surface antigen expressed in some derivatives of celomic epithelium, predominantly in ovarian cancer cells. However, it has also been detected in serum of healthy women and in patients with benign gynecologic diseases. The exact source or sources of the circulating levels of CA 125 and their elevations are not known. In the present study, the relationship between serum CA 125 levels, ovarian steroidogenesis and endometrial thickness is investigated at different periods: 1) mid-follicular, 2) midcycle, and 3) midluteal phases in normal cycles of fertile women, in patients stimulated for intrauterine insemination (IUI) and in patients stimulated for in vitro fertilization (IVF). Only in patients with mild and moderate ovarian hyperstimulation (OHSS) of the IVF group were luteal phase CA 125 levels (149.7 +/- 24.4 U/ml) significantly higher than midfollicular (21.2 +/- 1.9 U/ml) and midcycle phase levels (24.4 +/- 2.5 U/ml) (p < 0.001). The mean midcycle estradiol and midluteal progesterone concentrations in patients stimulated for IUI and IVF were significantly higher than those of normally cycling women (p < 0.001). Mean endometrial thickness in patients stimulated for IVF was significantly higher than in patients stimulated for IUI and normally cycling women (p < 0.001). Midluteal CA 125 levels correlated with midcycle endometrial thickness (r = 0.585, p < 0.05) and midluteal P levels (r = 0.497, p < 0.05) in patients with OHSS of IVF group. This correlation was not observed in patients who had no signs and symptoms of OHSS during stimulation for IVF and in patient stimulated for IUI and the controls.