Blister packs reminded women when to take the pill. Manufacturers designed special packaging such as this soon after the oral contraceptive pill launched in the 1960s. Monophasic pills such as Norinyl-2 (shown on the top left) are taken for 21 days with a week in between packets. The first pill is taken on the fifth day of a period and then at the same time of day for 21 days. 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. The pills are shown with other oral contraceptives.