‘Prevision’ is one of the earliest brands of oral contraceptive pills known as ‘first generation’ pills. Monophasic pills (like the one shown at the bottom of this image) are taken for 21 days, at the same time each day, with a week in between packets. The pill suppresses ovulation, which is the release of eggs into the womb. They also make it difficult for sperm to reach an egg, or for an egg to implant itself in the lining of the womb, all preventing pregnancy. First generation pills were introduced in the 1960s. They had high levels of hormones, which caused heart problems and increased the risks of heart attacks and strokes. Later contraceptive pills had much lower doses of hormones. The pills are shown with other oral contraceptives.