Compounds interfering with ovum implantation and development – The role of estrogens

Though this study was not statistically significant, it represented the first time that prevention of implantation was demonstrated – with DES usage – in humans


“It has been known for many years that estrogens interfere with early pregnancy in the rabbit and other specics.”…

…”In spite of evidence that success in the macaque should be paralleled by success in man, initial human experimentation was undertaken with some trepidation.

The first cases were rape cases. All of the subjects received 50 mg. of stilbestrol for 4 to 6 days after exposure. The chance of pregnancy following rape is uncertain for many obvious reasons. Sometimes no sperm could be found in the cervix or vagina. In a few instances, temperature charts were started; if no rise occurred, no drug was given. In most of the cases accepted for treatment, exposure occurred near midcycle and fern crystallization of cervical mucus as well as presence of sperm were demonstrated. In this small series of patients, none has become pregnant so far. The subsequent menstruation was generally unremarkable, although in some instances it was either scantier or more profuse or prolonged than usual. Side effects, when they occurred, were those usually associated with administration of estrogen; they consisted of nausea and breast soreness, which ceased shortly after medication was stopped.

A limited number of courageous volunteers furnished an opportunity for further and more adequate observation. Coitus took place at midcycle near the time of the temperature rise. Fern crystallization and Huhner tests with motile sperm were obtained
in most instances.

The apparent effect of 5 to 50 mg. of stilbestrol or 0.5 mg. of ethinyl estradiol on the biphasic temperature curve chart is to counteract the thermogenic effect of progesterone or to shorten the luteal phase.

From these charts it was anticipated that the secretory changes in the endometrium might be altered. However, instead of a proliferative or hyperplastic endometrium, endometrial biopsies taken on postovulation days 5 to 7 and 10 to 12 showed a progestational effect with secretion in some instances on both sides of the nucleus, occasionally almost suggestive of an Arias-Stella reaction. The stroma was dense in some areas, markedly edematous in others. Basal vacuolization often persisted up to menstruation, sometirnes giving an early secretory appearance late in the cycle.

In these preliminary trials there have been no pregnancies. While of interest, these clinical studies are incomplete and have as yet no statistical significance.” …


  • Compounds interfering with ovum implantation and development. 3. The role of estrogens, American journal of obstetrics and gynecology, NCBI PubMed PMID: 4959099, 1966 Nov.
  • Image credit thinglink.

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