Mini pills that contain only one hormone (progestin). They do not contain estrogen and may be prescribed in women who are breastfeeding or in women who experience nausea with estrogen. there are side effects of birth control pills, although the majority are not serious. Side effects include: Nausea, Weight gain, Sore or swollen breasts, Small amounts of blood, or spotting, between periods, Lighter periods, Mood changes...