Letter: Post-coital estrogen.

: The efficacy of Premarin as a postcoital contraceptive agent was eva luated in 194 women. The patients were instructed to take 4 2.5 mg tablets 3 times a day for 5 days. There were no pregnancies. Menses began on the average of 1.1 days before the expected menstrual period, and was not altered by the treatment. Should the treatment fail to prevent pregnancy, abortion is recommended if desired.