Heavy menstrual bleeding (HMB) has been defined as menstrual blood loss of 80 ml or more.¹ Abnormal uterine bleeding (AUB) is a broad term that describes abnormalities in the menstrual cycle involving regularity, frequency, duration and volume of flow outside of pregnancy.²

HMB can be caused by fibroids (growth that appear on the uterus), uterine polyps (clumps of cells) or endometriosis (a disorder in which the tissue that normally lines the uterus grows outside it). Coagulation disorders and endocrine disorders can also cause HMB.³ One of the causes of AUB is friable endometrial tissue, which is the inner lining of the uterus. The friable endometrial tissue is likely caused by unopposed oestrogen, which leads to heavy, continuous uterine bleeding.⁴

Medical therapies to treat HMB include oral contraceptives, which contain the hormones oestrogen and progesterone. They suppress ovulation (process by which a mature egg is released from the ovary) and fertility and regulate the ovulatory cycle by thinning the endometrium (inner lining of the uterus), which eventually leads to a lighter withdrawal bleed. This kind of bleeding is different from the bleeding that occurs during the natural ovulatory cycle. This therapy is conducted in a 21-day treatment cycle followed by a 7-day break.³

Progesterone is a hormone that is produced during the luteal phase (in the second half of the menstrual cycle, after ovulation) of the menstrual cycle. It leads to the secretory transformation of the endometrium. In the absence of fertilization, bleeding occurs once the oestrogen and progesterone levels fall.³ Combined oral contraceptive pills or oral progestins can be used as treatment for acute AUB. According to a study, treatment with either medication for 1 week stopped the bleeding within 3 days for 76–88% of the women.⁴

References:

1. Sriprasert I, Pakrashi T, Kimble T et al. Heavy menstrual bleeding diagnosis and medical management. Contracept Reprod Med. 2017;2:20.
2. Davis E, Sparzak PB. Abnormal uterine bleeding. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022.
3. Beebeejaun Y, Varma R. Heavy menstrual flow: current and future trends in management. Rev Obstet Gynecol. 2013;6(3/4):155–
4. Walker MH, Coffey W, Borger J. Menorrhagia. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022.