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Progestin Contraceptive Injections

By

Frances E. Casey

, MD, MPH, Virginia Commonwealth University Medical Center

Last full review/revision Feb 2022
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Depot medroxyprogesterone acetate (DMPA) is a long-acting injectable formulation of medroxyprogesterone acetate in a crystalline suspension. Other contraceptive injections are available elsewhere in the world.

With DMPA, pregnancy rates in the first year are 0.2% with perfect use and about 6% with typical use (ie, delays between injections).

DMPA may be given as an IM (150 mg) or subcutaneous injection (104 mg) every 3 months. The injection site is not to be massaged because doing so may increase the rate of absorption. Effective contraceptive hormonal serum levels are usually attained as early as 24 hours after injection and are maintained for at least 14 weeks although levels may remain effective for up to 16 weeks. If the interval between injections is > 16 weeks, a pregnancy test should be done to rule out pregnancy before the next injection is given. DMPA may be started immediately (a quick-start protocol) if DMPA is given within the first 5 to 7 days of the menstrual cycle. If it is not started during this time frame, a backup contraceptive method should be used concurrently for 7 days.

DMPA may also be given immediately after a spontaneous or induced abortion or immediately postpartum regardless of breastfeeding status.

Adverse effects

The most common adverse effect of DMPA is irregular vaginal bleeding. In the 3 months after the first DMPA injection, about 30% of women have amenorrhea. Another 30% have spotting or irregular bleeding (usually light) > 11 days/month. Despite these bleeding abnormalities, anemia does not usually result. With continued use, bleeding tends to decrease. After 2 years, about 70% of DMPA users have amenorrhea.

Because DMPA has a long duration of action, ovulation may be delayed. After the last injection, a regular menstrual cycle resumes in about half the women within 6 months and in about three fourths within 1 year. However, ovulation may be delayed for up to 18 months. After ovulation occurs, fertility is usually rapidly restored.

Women typically gain 1.5 to 4 kg during the first year of DMPA use and continue to gain weight thereafter. Because changes in appetite rather than metabolism are thought to be responsible, women who want to take DMPA are usually advised to limit caloric intake and increase energy expenditure.

In some studies, 1 to 5% of women using DMPA reported depression of mood changes. However, baseline scoring before starting DMPA was not accounted for. In well-designed studies, no evidence of exacerbation of preexisting depression by DMPA was found.

Headache is a common reason for stopping DMPA, but severity tends to decrease over time. Most women using DMPA do not have headaches, and preexisting tension headaches or migraines usually do not worsen.

Mild, reversible deterioration of glucose tolerance and lipid profile may occur.

Although bone mineral density may decrease when estrogen levels are low, there is no evidence of increased fracture risk, and bone scanning is not recommended for women who use DMPA. Adolescent and young women who use DMPA, like those who do not, should consume 1500 mg of calcium and 400 units of vitamin D daily; supplements should be taken if necessary. Bone density usually returns to baseline after injections are stopped.

Benefits

Unlike combination oral contraceptives, DMPA does not increase the risk of hypertension. Progestins are not believed to increase the risk of thromboembolism; however, some data in some studies suggest that use of DMPA may increase the risk of thromboembolism; DMPA is associated with an increase triglyceride and low-density lipoprotein (LDL) cholesterol levels. However, the association between DMPA and thromboembolism is not well-established, and DMPA is considered safe for women with contraindications to estrogen use.

DMPA does not appear to increase the risk of breast, ovarian, or cervical cancer.

DMPA reduces the risk of

Some evidence suggests DMPA may reduce the incidence of painful crisis in women with sickle cell disease.

DMPA may be an appropriate contraceptive option for women with a seizure disorder because it does not interact with antiseizure drugs that induce liver enzymes.

Drugs Mentioned In This Article

Drug Name Select Trade
PROVERA
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NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
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