[Light and electron microscopy changes in the endometrium caused by the administration of a norgestimate-containing oral contraceptive (Cilest)].

: Endometrium morphology has been analysed by means of light microscopy, scanning and transmission microscopy in patients before and during treatment with a norgestimate containing low dose combined pill (Cilest). Endometrium biopsies were taken after 1 (N = 3), 2 (N = 3), 3 (N = 7), 5 (N = 1) and 6 (N = 4) OC cycles. Light microscopy of the endometrium obtained during the OC-free pretreatment cycles shows a regular secretory transformed endometrium. During the first OC cycles of Cilest treatment slight growth retardation of endometrial glands was observed. Endometrium after 3 to 6 OC cycles showed an increasing delay of the growth of 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 the endometrium presented mostly a regular surface corresponding to the midcycle or a 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 semi-thin and ultrathin slices, stroma, structure of glands and surface appeared to be normal. Furthermore, no time delay between the endometrium and the day of menstrual cycle was observed. During treatment with a norgestimate containing low dose combined pill, only slight changes of the endometrium in terms of a growth retardation of endometrial glands were seen in the first 6 treatment cycles.(ABSTRACT TRUNCATED AT 250 WORDS)