Other Effects
After menstrual changes, weight gain, headache, and
dizziness are the most common side effects reported by users of
progestin-only injectables. Other reported side effects include
abdominal distension or discomfort, acne, anxiety, backache,
decreased libido, fatigue, hair loss, moodiness, tender breasts,
and weight loss. Rates of discontinuation for all these side
effects combined have ranged from 3% to 9% after 12 months in WHO
trials (336, 338, 340, 342). Progestin-only injectables change
cholesterol metabolism in ways that are suspected to increase
users' risk of atherosclerosis (thickening and hardening of
arterial walls).
Weight gain. Most users of injectables gain weight. On
average, DMPA users gain 1.5 kg to 2.0 kg in the first year (285,
333, 338, 341). Some users may continue to gain weight thereafter
at about the same rate (276). A Thai study found that long-term
DMPA users gained weight steadily for five years and then stopped
gaining weight (315). NET EN users gained an average of 1.5 kg in
a 1-year WHO trial (341). Among users of Cyclofem and Mesigyna in
a WHO trial, weight gain averaged 0.8 kg per year (336). In
contrast, the vast majority of women using OCs do not gain weight
(116).
The range of weight change is wide. In studies some users
have gained considerably more than 2 kg a year, others' weight
has not changed, and some women have lost weight (8, 54, 122,
190, 270, 285, 338). In a 1-year trial, for ex- ample, the
average weight gain among 607 DMPA users was 1.5 kg, but six
women discontinued because they gained between 4 kg and 13 kg
(338). A study of NET EN users found an average gain of 5 kg
among 20% of women and an average loss of 5 kg among 15% of the
women after one year (122). In a 3-year study of Mesigyna,
one-third of users gained 3 to 8 kg (157).
The reason for weight gain is unclear. The extra weight is
mainly from fat rather than water retention. Some users report
increased appetite (8, 112, 315). In contrast, among OC users
both increased water retention and fat may cause the occasional
weight gain (116). Some weight gain is normal with increasing
age, of course. For example, in a multiyear Swedish study, normal
weight gain accounted for about half of the average weight gain
of DMPA users (285).
Few women discontinue injectables because of weight gain.
Among DMPA and NET EN users in a 2-year WHO trial, the rate of
discontinuation for weight gain was about 2 per 100 woman-years
(342). There are regional differences in women's perceptions of
weight gain, perhaps reflecting cultural differences in women's
ideal weight. In a WHO introductory trial of Cyclofem, rates of
discontinuation for weight gain ranged from 0.4 per 100 after one
year in Indonesia to 4.0 per 100 in Thailand (110).
Cholesterol metabolism. Most studies
find that DMPA and NET EN increase levels of low-density lipoprotein (LDL)
cholesterol and decrease levels of high-density lipoprotein (HDL) cholesterol
(see Table 4). LDL
cholesterol has been linked to atherosclerosis, while HDL cholesterol
reduces the risk of atherosclerosis. Atherosclerosis is a major cause
of heart attack, stroke, and other vascular disease (360). There is little
direct epidemiologic information, however, on the risk of vascular disease
among users of injectables.
Headache and dizziness. In clinical trials anywhere from 3%
to 19% of users of injectables have reported headache or
dizziness. Few women discontinue use for these reasons (80, 270,
336, 340, 341, 342). For example, among DMPA and NET EN users in
one clinical trial, the rate of discontinuation for headache in
both groups after two years was about 2 per 100 woman-years of
use. The rate of discontinuation for dizziness was 1.2 per 100
woman-years among DMPA users and 1.6 per 100 among NET EN users
(342). Among 2,320 users of monthly injectables in a one-year
study, about 2% had headaches or dizziness, but less than half of
these women discontinued for these reasons (336).
Headaches may not be caused by injectables but rather may
occur at rates typical of the general population. In a
comparative trial of IUD and Norplant users, for example, 7% to
10% of IUD users reported headaches (253). Most headaches in
adults are caused primarily by muscle tension rather than
vascular problems and thus clearly are not related to hormonal
contraception (366). There is no medical reason for women to
discontinue injectables because of headaches, even migraine
headaches, unless they are accompanied by focal neurologic
symptoms—difficulty seeing, speaking, or moving (332). Women may
choose to discontinue for personal reasons, however.
Clinical implications. For women reporting side effects on
return visits, providers should first consider other causes. For
women with severe headaches, providers should consider sinus
infection, high blood pressure, and stroke. Anemia, high or low
blood pressure, or low blood sugar could cause dizziness. Lack of
exercise or pregnancy could cause weight gain. In some instances
providers can encourage women concerned about weight gain to diet
and exercise more.
If other causes are unlikely, these side effects often can
be handled through counseling. Clients may need reassurance that
these side effects are not dangerous and are not symptoms of more
serious problems. If, after counseling, a client insists that
side effects are unacceptable, providers should recommend that
she choose another method and help her to do so without
expressing criticism or disapproval (259).
To provide support and reassurance, providers emphasize that
clients should return for help whenever they have problems or
questions. If possible, clients who receive injections at a
clinic should return there for help because those providers are
trained to handle side effects of injectables. Inexperienced
providers at other clinics may respond inappropriately—for
example, treating bleeding by dilation and curettage (23).
Because of the effect of progestin-only injectables on cholesterol levels,
a group of experts assembled by WHO recommends that women with severe
vascular diseases (such as severe hypertension, a history of stroke, or
ischemic heart disease) or with diabetes involving vascular complications
should not use these injectables unless other methods are not available,
or, in a provider's careful clinical judgment, other methods would not
be acceptable. Women who develop these conditions while using progestin-only
injectables or who develop recurrent severe headaches with focal neurologic
symptoms should see a doctor or nurse and switch to a nonhormonal contraceptive
method because there is some concern that such headaches sometimes progress
to stroke (332) (see Chapter 9.3 Eligibility
Criteria.
