TABLE B1.4 Uses of RU 486


5–9 weeks of amenorrhea

Occasional luteal contragestion

Once-a-month menses induction

Emergency contraception

Once-a-month anti-implantation

"Endometrial" contraception

Suppression of ovulation

Medical Interruption of Pregnancy

Second trimester

Third trimester

Labor Induction

Medical Indications



Uterine fibroid

Breast cancer



Endocrine test

"Peripheral" hypercorticism


Wound/burn healing

observations made in vitro, as discussed above.

Thus, administration of RU 486 may produce effects in different directions, which have to be studied separately in each tissue. However, to provoke abortion or trigger labor, the effects on the decidua, endometrium, cervix, and even the trophoblast combine to make RU 486 a very efficient agent for the termination of pregnancy.

Voluntary Early Pregnancy Interruption

On the basis of animal experiments, we expected RU 486 to meet the recognized need for an efficient medical means of early abortion, to be safer than a surgical technique, and to be relatively convenient and cheap (no anesthesia, no operating room). To develop a medical method of abortion was a must in terms of women's health and potentially a step toward more privacy for those having taken the difficult decision of pregnancy termination.

Early abortion offered the first opportunity to test RU 486 activity in

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