Linear regression analysis of ultrasound follicular growth series: evidence for an abnormality of follicular growth in endometriosis patients.

Follicular diameter growth is a highly linear function of time. Recently, the potential utility of linear regression-derived parameters for describing and comparing cycles of follicular growth was described. The linearity of growth, growth rate constant (K), calculated date of growth onset (Do), total growth period (TGP), menstrual age at apparent ovulation (MAov), and peak follicular diameter (PFD) have been calculated from the follicular growth series of a group of patients with laparoscopically diagnosed endometriosis (n = 46). These parameters were compared with those of a group of normal volunteers (n = 18). The authors found significant differences between endometriosis patients and controls in follicular growth rate and total growth period. The effect of patients' clomiphene citrate usage on growth parameters in these patients was examined. Abnormalities in interrelationships between the growth parameters were detected, suggesting the possibility of subtle defects in the regulation of follicular growth in these patients.