If you started birth control pills for the first time can your first period be shorter or lighter than usual?

On hormonal Birth Control you no longer menstruate.

They pill works by stopping your menstrual cycle to prevent ovulation, no ovulation means no menstruation. The bleeding you experience on the pill is a withdrawal bleed caused by the drop in synthetic hormones when going from active to inactive pills.

It takes time for your body to adjust to this change so irregular bleeding is normal for the first three months on any new form of hormonal birth control. Withdrawal bleeds are also lighter than menstrual bleeds as the pill also prevents uterine lining build-up.