Pharmacological Prevention of Pregnancy Female Contraception

The most effective means of preventing ovulation is by the oral administration of ovulation-inducing gonadal steroid derivatives at dosages that will prevent cyclic changes in LH and FSH secretion. This method has proven to be more than 99% effective over the past 40 years and is currently used by more than 50 million women worldwide. The treatment protocol is of four different types, all of which involve the use of synthetic steroid 

Structures of steroids used as oral contraceptives. (A) Combination pills containing an estrogen -P progestin. (B) The progestin-only pill. (C) RU-486 or mifepristone, which can be utilized as an abortifacient. [Reproduced with permission from S. W. Norman and G. Litwack, Hormones, 2nd ed. San Diego Academic Press, 1997]. 

Fixed combined dose of estrogen -f progestin daily ( combination pill )  

Biphasic type fixed dose estrogen + two different doses of progestin  

Triphasic type fixed dose estrogen - - three different doses of progestin (stepwise increase at 1-week intervals) and 

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