Are birth control pills an effective means of contraception, or can condoms also be used for this to be sure?

Birth control pills prevent pregnancy usually by inhibiting ovulation, thickening mucus in the cervix and altering the endometrium to prevent embryo implantation. Contraceptive pills, like any medicinal product, were tested for efficacy before being placed on the market for use by patients. When a pharmaceutical company placed a drug on the market, it had to prove that it was effective and safe for patients. Therefore, she conducted so-called clinical trials first on experimental animals, and then on humans. Properly taken contraceptive pills are a very effective method of protection against pregnancy. By "correctly" I mean not only not skipping the pills, but also taking them regularly - at fixed intervals. Although it is not a 100% effective method, the probability of pregnancy is very low and many couples do not opt for additional methods of pregnancy prevention if the partner takes contraception correctly. In combination with a condom, the tablets give a near-zero risk of pregnancy, but it is never and will not be zero, although the probability that both methods will fail at once is negligible. Each contraceptive pill has a specific so-called Pearl index, which can be found in the leaflet or Summary of Product Characteristics. The Pearl Index (index) represents the number of unwanted pregnancies that occurred during regular sexual intercourse in 100 couples using a given method of contraception for a year. The lower the value of the Pearl index, the more effective the contraceptive method. Pills, but also other hormonal contraceptives are effective methods. However, there are occasional unplanned pregnancies - this is more likely if a woman does not use the pills correctly, e.g. she takes them irregularly or skips them, or if there are factors that reduce the effectiveness of the drug. I submit materials that may be useful: https://www.gdziepolek.pl/artykuly/jak-prawidlowo-stosowac-antykoncepcje https://www.gdziepolek.pl/artykuly/jakie-leki-oslabiaja-skutecznosc-antykoncepcji