Hi,
Menstrual cycle starts from the 1st day of cycle to the first day of the next cycle. The cycle is divided into two phase
follicular phase and luteal phase separated by ovulation.
Estrogen and
Progesterone are the hormones that play roles in maintenance of menstrual cycle.
Menstruation is the shedding of the developed uterine endometrial lining which is otherwise accommodate the fertilized egg and maintains the
pregnancy. If the egg released during ovulation is not fertilized, the progesterone levels falls over time which induces shedding of the uterine tissue.
Birth control pills contain either both estrogen and progesterone or progesterone only acts as contraceptives by preventing the ovulation, inhibits the growth of uterine endometrial lining and changes the consistency of the cervical mucus which in turn inhibits sperm motilization. Side effects of the drug causes nausea, headache, breast tenderness, spotting and the withdrawal bleeding. This may be the reason for heavy bleeding. If the bleeding not controlled in time, visit the gynecologist for further management.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Pradeepraj, General & Family Physician