Light microscopic and electron microscopic changes in human endometrium during treatment with a new norgestimate containing low dose combined pill (Cilest)

Endometrial morphology has been analyzed by means of light microscopy scanning and transmission microscopy in patients before and during treatment with a norgestimate-containing low dose combined pill (Cilest). Endometrial biopsies were taken after 1 (n=3) 2 (n=3) 3 (n=7) 5 (n=1) and 6 (n=4) oral contraceptive (OC) cycles. Light microscopy of the endometrium obtained during the OC-free pretreatment cycles shows a regular secretory transformed endometrium. During the 1st OC cycles of Cilest treatment slight growth retardation of the endometrial glands was observed. Endometrium after 3-6 OC cycles showed an increasing delay of the growth the endometrial glands in terms of an abortive secretion. Morphometric studies revealed a retardation of the development of endometrial glands and "an arrest of secretion". The degree of proliferation varied slightly; a general delay between the date of the menstrual cycle and endometrial dating was evident. Using scanning electron microscopy of the endometrium presented mostly a regular surface corresponding to the midcycle or late proliferative phase up to the early secretory phase. Infiltrative dysplasia or inflammatory changes as well as local proliferations could not be detected. In transmission electron microscopy with semithin and ultrathin slices stroma structure of glands and surface appeared to be normal. Furthermore no time delay between the endometrium and day of menstrual cycle was observed. During treatment with a norgestimate-containing low dose combined pill only slight changes in the endometrium in terms of a growth retardation of endometrial glands were seen in the 1st 6 treatment cycles. This delay in endometrial development could also be shown by electron microscopy. No proliferative infiltrative or inflammatory changes of the endometrium were noted. The data showed that a sufficient secretory transformation of the endometrium occurs in Cilest-treated patients. (authors) (summaries in ENG GER)