Breakthrough bleeding


Breakthrough bleeding is any of various forms of vaginal bleeding, usually referring to mid-cycle bleeding in users of combined oral contraceptives, as attributed to insufficient estrogens. It may also occur with other hormonal contraceptives. Sometimes, breakthrough bleeding is classified as abnormal and thereby as a form of metrorrhagia, and sometimes it is classified as not abnormal.
In the context of hemophilia, the term describes a bleeding that occurs while a patient is on prophylaxis.

Presentation

The bleeding is usually light, often referred to as "spotting," though a few people may experience heavier bleeding.
Breakthrough bleeding generally is greatest in the first 3 to 4 months after starting oral contraceptives, and it steadily declines and stabilizes by the end of the fourth cycle.
It is estimated that breakthrough bleeding affects around 25 % of combined oral contraceptive pill users during the initial 3 months of use.

Mechanism

Breakthrough bleeding is commonly due to 4 factors: physiologic effects of OCs on the endometrium, OC-related parameters, , patient behavior, and benign or malignant pathology.
As for the first factor, studies have shown that an increased estrogen dose in combined OCs leads to a lower incidence of breakthrough bleeding. Studies also reported that the ratio of estrogen/progestin in combined OCs may be more important than the absolute value of estrogen in the incidence of breakthrough bleeding.

Treatment

Breakthrough bleeding that does not resolve on its own is a common reason for women to switch to different pill formulations, or to switch to a non-hormonal method of birth control.