Both periods and withdrawal bleeding lead to shedding of the uterine lining. However, withdrawal bleeding tends to be less heavy because the synthetic hormones in birth control prevent the lining from building up as much. Additionally, an egg is only released during a normal period (not during a withdrawal bleed).

Why is my withdrawal bleeding heavy?

Much like a regular menstrual period, withdrawal bleeding is caused by a drop in hormone levels in the body. The drop in hormones triggers the release of some blood and mucus from the lining of the uterus out through the vagina.

What does a withdrawal bleed look like?

Withdrawal bleeding is usually lighter and slightly different than the period you had before taking the pill. Some people experience only very light bleeding or don't bleed at all during placebo pill days. Your bleeding on the pill is likely to change over time.