DES mode of action as contraceptive agent

Letter: The “morning after” pill, 1973


The use of diethylstilbestrol (DES) as a postcoital contraceptive agent is discussed.

DES is associated with nausea, an increased risk of thrombosis, and is suspect in endometrial and breast cancer, and vaginal cancer in the progeny of mothers treated during pregnancy.

Postcoital estrogens do not seem to be as effective as conventional oral contraceptives. Although DES is most likely not an abortifacient agent, its mode of action is not certain. Nonetheless, the relatively high number of ectopic pregnancies among method-failures suggests that DES delays ovum transport.

It is concluded that routine postcoital use of DES is too hazardous, and that abortion is strongly indicated if the method fails.


  • Letter: The “morning after” pill, The Medical journal of Australia, NCBI PubMed PMID: 4765882, 1973 Nov.
  • Featured image hopectr.

Have your say! Share your views