In order to protect you from becoming pregnant, Apri works in three ways.
The birth control pill affects ovulation. Ovulation is when an egg is released from the ovary. The pill might stop ovulation completely but it’s not a guarantee.
Apri has an effect on the mucus in your cervix too. When you’re using the pill, it thickens the mucus so it’s harder for sperm to get through, and then reach an egg.
The hormones in Apri also impact the uterine lining. This lining, when you aren’t using hormonal birth control, builds up naturally over the month. When the lining comes away, this is when you have your period. But when you’re using Apri birth control pills, this lining doesn’t build up as normal. As a result, your lining is much thinner and your bleed tends to be a lot lighter than it normally would be.