[Estrogens in contraception].

Ehtinylestradiol (EE) and Mestranol (ME) are oral highly effective estrogens. They inhibit pituitary FSH and LH and thus cause inhibition of ovulation. This effect is synergistically increased by progestogens. 50 micrograms EE or ME per day are the minimal dose for inhibition of ovulation for a duration of 8 days. The metabolism of EE and ME is different from that of natural estrogens. They are very little metabolized and have a longer half life. Oral hormonal contraceptives with an estrogen contain either EE or ME. Their doses have been lowered in the last years. The possibilities of contraception with one-phase-, two-phase-, and step-up-preparations and especially the estrogen part of their effects and some side effects are discussed.