Pregnancy rate of a progestogen oral contraceptive

The results of this survey show that 0.5 mg of ethynodiol diacetate (Femulen) is a reliable oral contraceptive with a pregnancy rate calculated by the Pearl Index of 0.52 per 100 women years. This is superior to the failure rates for both 0.075 mg dl norgestrel and 0.35mg norethisterone and approximates more closely with the claimed failure rates for combined oestrogen/progestogen preparations. There is no evidence which suggests that side effects occur with prolonged use of Femulen therapy.