Effect of postovulatory adminstration of a “morning-after” injection on corpus luteum function and endometrium

Abstract

Five healthy female volunteers were given the “morning-after” injection intramuscularly 1–4 days after midcycle LH peak. The medication consisted of 12.5 mg of estradiol-benzoate and 10 mg of estradiol-phenylpropionate. In both control and treatment cycles, ovulation was determined according to the pattern of urinary total estrogens and LH as well as the rise in basal body temperature. After the LH peak, daily plasma samples were obtained for protein binding assay of progesterone. Plasma progesterone levels were unchanged in two cases and slightly suppressed in another two, while in one case the effect of the medication was moderate. At the end of treatment cycles, endometrial biopsies were taken and histological evaluation revealed dissociation or pronounced local epithelial proliferation of the secretory endometrium in three of five cases observed. The pattern of postovulatory basal body temperature recordings remained unchanged. The length of the mentrual cycle was shortened by two days in one of the participants and by four days in another one. Menstrual patterns after the treatment cycles were unchanged. No side-effects were recorded. In the efficacy study of 150 volunteers, treated so far, a low frequency of side-effects was reported. Unfortunately, four pregnancies considered to be method-failures, were seen in these 150 cases.