Only about 10% of DMPA users have normal cycles in the first year of use. DMPA users can expect to have irregular bleeding in the first six months and then infrequent bleeding or amenorrhea in the next six months and beyond. By comparison, in a WHO trial of six OCs, 59% to 87% of women had normal bleeding patterns after one year (349).

NET EN has somewhat less effect on bleeding patterns than DMPA. In a comparative trial bleeding episodes in the first six months were significantly shorter among NET EN users than among DMPA users. Bleeding patterns after six months were similar, however. Amenorrhea lasting more than 90 days was significantly less common among NET EN users (342).

With monthly injectables, about half of women have regular bleeding during the first year of use (see Table 5). Users tend to have irregular or prolonged bleeding in the first three months and then increasingly regular patterns by the end of the first year (272, 331). In particular, the first bleeding interval may be shorter than usual (157). With monthly injectables, most women have bleeding 10 to 15 days after the first injection and then every 30 days after that. Thus women have regular bleeding 10 to 15 days after each injection (336).

Bleeding patterns may differ among ethnic groups. Southeast Asian women using DMPA, for example, report more days of bleeding and spotting than women in the Caribbean, Europe, South Asia, or North Africa. North African women report amenorrhea more often than European women. The full reasons for these differences are not known. Some of the variation may be due to regional differences in the nutritional status of users, sensitivity to menstrual changes and thus reporting, and accuracy of menstrual diaries (32).

Individual differences may also affect bleeding patterns. For example, among DMPA users in a WHO trial, heavy women tended to have more amenorrhea and less bleeding than lighter women. Among women using NET EN, however, there was no relationship between weight and amenorrhea (341). Bleeding patterns of individuals cannot be predicted.

Discontinuation of use because of menstrual bleeding changes or amenorrhea in WHO trials reflected their differing effects on bleeding patterns. After one year 15% of DMPA users had discontinued use because of bleeding changes, and about another 12%, because of amenorrhea. NET EN users discontinued for bleeding problems at about the same rate as DMPA users, but only 7% discontinued because of amenorrhea. About 7% of users of monthly injectables discontinued for bleeding problems, and only about 2% discontinued because of amenorrhea (89, 157, 331, 338, 340, 342). Frequent bleeding or a worsening pattern—a change from a regular pattern to amenorrhea or infrequent bleeding, for example—was especially likely to lead to discontinuation (103, 337).

Discontinuation rates vary widely among regions. In a one-year study of DMPA, for example, Thai women had a median of 4.7 months without bleeding or spotting, but none discontinued because of amenorrhea. Egyptian women, in contrast, had a median of 5.0 months without bleeding or spotting, and 27% discontinued because of amenorrhea (338). Counseling may have influenced these discontinuation rates.

The reasons that women give for stopping a method, however, may not always be the real reasons. Some may want to stop for a personal reason, but, afraid the provider will not accept it, they give medical reasons instead. Others may have been troubled by a number of side effects but tell providers only about the one that made the most difference. For example, in a clinical trial of DMPA, almost two-thirds of women who discontinued citing other medical or nonmedical reasons or who were lost to follow-up after several injections had severely disrupted bleeding patterns (339).

Clinical implications. Since bleeding patterns vary among injectables, programs may offer clients a choice. In Namibia, for example, providers recommend NET EN over DMPA for younger clients partly because, providers say, it causes less menstrual disruption (186). In introductory trials of Cyclofem in Indonesia, Jamaica, and Thailand, 36% to 45% of women had switched from DMPA mainly because of bleeding problems (110). Offering several injectables may pose logistical problems, however (see Chapter 9.2 Ensuring Reliable Supplies. Counseling can help women deal with menstrual bleeding changes or amenorrhea (see Chapter 7 Counseling Issues and Counseling Guide).

Some women using progestin-only injectables cannot accept frequent bleeding despite counseling. They have no choice but to continue for several months, until the injectable wears off. Providers have used several approaches to decrease bleeding.

If estrogens are not contraindicated, providers have given one to three weeks of combined oral contraceptives or of estrogen, which temporarily reduce or stop most episodes of bleeding. For example, in a WHO study among women with bleeding lasting seven days or more during the first six months of DMPA use, 93% of women given ethinyl estradiol stopped bleeding while under treatment compared with about three-quarters of women given a placebo, a significant difference (60). Women also have used OCs for a few months to get over initial irregular bleeding caused by DMPA.

Over the long term, however, estrogen may be no more helpful than counseling. After treatment in the WHO study, women given ethinyl estradiol had fewer bleeding days but more varied patterns than women given the placebo, and after one year rates of discontinuation for bleeding were the same for both groups (60).

Anti-inflammatory drugs (except aspirin) also have helped to control bleeding. Ibuprofen and other nonsteroidal anti-inflammatory drugs block the synthesis of prostaglandins, which induce bleeding (299).

Giving the next injection of DMPA or NET EN early can temporarily reduce bleeding among women who want to continue despite bleeding problems. Injections generally should not be given sooner than four weeks after the previous injection, however (299).

Women with heavy or prolonged bleeding—twice as much or twice as long as usual for them—require special care. Such bleeding is unusual and rarely requires treatment. A survey of 35 researchers in 20 countries found that 1% to 2% of users have heavy bleeding (88). Only 6 of 1,200 women participating in a WHO multicenter trial required treatment for heavy bleeding, and in the first 10 years of the McCormick Family Planning Program in Thailand, only two of more than 70,000 DMPA users had very heavy bleeding that was considered a medical complication (20, 346). Nevertheless, programs must ensure that women using injectables can be treated for heavy bleeding.

Before treating heavy bleeding, providers should consider other causes of bleeding, such as pregnancy, cancer, or sexually transmitted disease, and should check for anemia. If estrogen is not contraindicated, providers may give women one to three weeks of combined OCs or 30 to 50 micrograms of ethinyl estradiol daily for 14 to 21 days. Uterine evacuation is not necessary unless another medical condition is suspected (299, 333).

Giving combined OCs to induce bleeding in amenorrheic DMPA users is not recommended. Counseling and reassurance are often effective. Providers may consider switching women to monthly injectables, however. WHO is studying the effect of switching DMPA users who dislike amenorrhea to Cyclofem (60).