RESEARCH TRIANGLE PARK, NC -- Modern contraceptive methods can profoundly affect menstrual bleeding patterns, with disturbances ranging from heavier bleeding, to prolonged or irregular bleeding, to no bleeding at all.
When discussing contraceptive method choices with their physician or other health provider, many women may not consider such disturbances or may minimize them. Unless bleeding irregularities result in medical problems, such as anemia, they are typically minor concerns. Disturbances may be transient or will change over time, reproductive health scientists say in the current issue of Network, the quarterly health bulletin of Family Health International. Some women, however, will not tolerate bleeding changes that are acceptable to others.
Women notice even minor changes in menstrual bleeding, according to a study conducted by the World Health Organization (WHO) of 5,322 women in 10 countries. Most women surveyed (well over half in most of the countries), including rural and urban women from various socioeconomic strata and various religious groups, did not want their menstrual cycles to change.
Among the ways contraceptives may influence menstrual cycles are the following:
Hormonal contraceptives that use progestins, like Norplant and the three-month injectable depot-medroxyprogesterone acetate (DMPA), change menstrual bleeding patterns in the majority of users. Progestin-only methods rarely increase the number of days of heavy bleeding, but they often increase the number of days of light bleeding or spotting, irregular bleeding and -- particularly in the case of injectables -- amenorrhea (absence of bleeding). The majority of women using progestin-only injectables report prolonged or irregular menstrual bleeding or amenorrhea in their first year of use. Later, injectables are associated with amenorrhea, with approximately two of every three DMPA users experiencing amenorrhea by the end of the second year.
Combined oral contraceptives (OCs or COCs), which use an estrogen hormone with a progestin, commonly decrease the number of days of bleeding and blood loss, with menstrual flow decreasing by 60 percent or more. However, missed periods, very scanty bleeding, spotting or breakthrough bleeding may occur. Amenorrhea also may be a side effect, especially in women using low-estrogen pills.
Increased menstrual bleeding is frequently reported by women using intrauterine devices (IUDs). With Copper T IUDs, menstrual blood loss is increased moderately (defined as a 30 percent to 50 percent increase in bleeding compared with the average loss for women not using modern contraceptive methods). FHI research conducted in 23 developing countries, however, indicates that Copper T IUD-related bleeding disturbances tend to decrease after the first few months of use.
Hormone-releasing IUDs significantly reduce the volume of menstrual bleeding. Progestasert, which releases the naturally-occurring hormone progesterone, is costly, not widely available, and is approved for only a year of use in the United States. A levonorgestrel-releasing IUD, called LNg-IUD, is available in several European and Asian countries, but not in the United States. The number of bleeding and spotting days in LNg-IUD users is markedly reduced when compared with non-users. A substantial proportion of users experience amenorrhea.
Further research is needed to determine whether sterilization can cause menstrual disturbances. A review of more than 200 studies on menstrual and hormonal changes in women who undergo tubal sterilization concluded that the procedure was not associated with an increased risk of menstrual dysfunction, painful menstruation, or increased premenstrual distress in women who underwent it after age 30.
