Hormonal contraception is a modern method of preventing unwanted pregnancy with 99.9% contraceptive success when used correctly and, most importantly, the return of reproductive functions after stopping them! Oral contraceptives are made of two ingredients – estrogen and progesterone. Ethinylestradiol is the most commonly used estrogenic ingredient found in all modern oral contraceptives. And while at the beginning of the 1960s the estrogen component was present in a very high dose – usually around 100 and more mcg, today the “low-dose” ones are preferred. Most contraceptives in use today contain 20 or 30 mcg of ethinyl estradiol. Estrogens in preparations cause most of the side effects of combined oral contraceptives. Some of these effects are dose-dependent. Reducing the estrogen dose is characterized by an increase in so-called breakthrough bleeding and “spotting” (bleeding or soiling of underwear that occurs outside the expected period of menstruation). Regarding contraceptive effectiveness, both 30 mcg and 20 mcg oral contraceptives provided highly effective protection, with no significant difference in terms of unintended pregnancies occurring. The frequency of breakthrough bleeding and spotting is more frequent with the lower-dose contraceptives – with 20 mcg of ethinyl estradiol. However, there is an established tendency to decrease the frequency of breakthrough bleeding with increasing duration of administration. The question of bone density in girls taking oral contraceptives during adolescence is raised. Estradiol is known to be a hormone extremely important for good bone health in both women and men. The minimum osteoprotective dose is thought to be about 10 mcg of ethinylestradiol. The variety of progesterone ingredients in oral contraceptives is wide. There are 4 generations, and today the “third” and “fourth” generation progesterones are preferred. Progestogens of the “first” generation are synthesized from steroids of plant origin. The main progestogen of the “second” generation is levonorgestrel. It quickly established itself in practice and became one of the most widely used progestogens in oral contraceptives. Unfortunately, it turns out that in addition to its higher affinity for the progesterone receptor, it also has a threefold higher affinity for the androgen receptor. The sought-after effects of modern progestogens are to have a high binding effect to the progesterone receptor and a low binding effect to the androgen receptor, such as the effects of “third” and “fourth” generation progestagens. How do they achieve their contraceptive effect? Oral contraceptives do not simply suppress ovarian activity and thereby achieve contraception, but provide a complex approach, such as: Suppress ovulation; They change the endometrium (the inner layer of the uterus); They change the cervical mucus (secretion released by the glands of the cervix); Changes in fallopian tube function.NEWS_MORE_BOX The main mechanism is, of course, suppression of ovulation, but with the other three additional effects, they become a 99.9% safe contraceptive method. Assessment of the effectiveness in terms of the contraceptive effect is done through the so-called “Pearl index” – number of pregnancies per 100 women using a certain method for 1 year, and it takes into account all pregnancies that occurred, both due to the ineffectiveness of the method and as a result of errors in its use. Nearly 50 years after its creation, the pill is an effective enough method of contraception. By drastically reducing the dose of ethinyl estradiol to 20 or 30 mcg over the years (and there are also 15 mcg preparations on the market) in combination with a progestagen of the “third” or “fourth” generation, it was possible to achieve a significant reduction in the side effects of the medication. Oral contraceptives also have additional non-contraceptive health benefits, which we will address in another article.