CDRI, being one of the leading research labs of the country had obviously put enough attention and intellectual resources to develop safer and acceptable antifertility drugs. One of the main focus was to have an alternative to steroidal pills available in the market which were not free from side effects.

The need for a safer alternative to Progestogen - Estrogen combination pills has been felt ever since the sixties. Clearer understanding of the role of estrogen-progesterone balance in the development of fertilized ovum and the priming of the uterus for implantation served as the basis for developing an agent that would prevent pregnancy by interfering with implantation but without disturbing the hypothalamus-pituitary-ovarian axis. Researchers the world over have been designing and synthesising non-steroidal estrogen antagonists that would act by disturbing the delicate balance between estrogen and progesterone at the uterine level without interfering with their synthesis or blood levels. This task was sucessfully completed by CDRI when the first non-steroidal once a week pil, centchroman was devloped by CDRI taht reached the general public by the end of the 1980's.
Centchroman is a novel non-steroidal agent unrelated to any conventionally used contraceptive. This is the only anti-implantation agent approved for clinical use in the world. It offers a unique combination of weak estrogenic and potent antiestrogenic properties. Due to this subtle mix of estrogenic and antiestorgenic action it inhibits the fertilized ovum from nidation and thus prevents pregnancy, but at the same time it does not appear to disturb the other estrogen effects.

Use of Centchroman as a contraceptive has been extensively evaluated in more than 2000 women of the reproductive age groups who wanted to space their children. Intensive monitoring by clinical examination, haematology and biochemical tests as well as laparascopy and ultrasonographic examinations of ovaries and uterus have shown the drug to be quite safe. Centchroman does not cause nausea, vomiting, dizziness and break through bleeding and has no adverse effect on lipid profile and platelet function as is seen with steroidal contraceptives. Babies born to use failure cases have shown normal milestones. The contraceptive effect is readily reversible and subsequent pregnancy and its outcome is normal. It scores over steroidal contraceptive pills because it does not disturb the endocrine system and the normal ovulatory cycle is maintained.