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DEPO-PROVERA*
Depot Medroxyprogesterone Acetate (DMPA) was approved in late 1992 by
the FDA for use as a long-acting, injectable contraceptive. Prior to 1992, many clinicians
had used DMPA for this purpose without explicit FDA approval.
 150 mg of DMPA are injected IM every three months, giving failure rates
of slightly less than 1%.
It is believed to exert its' contraceptive effect by some or all of the
following:
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Inhibiting ovulation
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Changing cervical mucous
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Changing the lining of the uterus
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Altering fallopian tube function
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Other, as yet unclassified mechanisms
Timing of Injections
The first injection is given within 5 days of the onset of menses. It is
considered effective 7 days after it is given.
DMPA should be given every 3 months, but there is a 2-4 week "grace
period" at the end of the three months during which DMPA can be given and
contraceptive efficacy remains unchanged.
If the injection is more than 2-4 weeks late, then backup contraception
should be used for the first month.
It may be given post-partum.
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For women not breast-feeding, it should be administered within the first
5 days after delivery.
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For women who are exclusively breast-feeding, it should be administered
during the 6th post-partum week.
Contraindications
The following are considered reasons to avoid giving DMPA. Some might be
considered absolute contraindications, while others are more relative. In general, you
should avoid both.
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Undiagnosed vaginal bleeding
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Known or suspected pregnancy
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Known or suspected breast cancer
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Active thrombophlebitis
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History of embolism or cerebrovascular disease
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Active liver disease or dysfunction
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Known hypersensitivity to DEPO-PROVERA
Bone Loss
Measurable changes in bone mineral density occur, but this loss is not
associated with an increased risk of pathologic fractures.
The greatest loss is early in the use of DMPA and slows with longer use. The clinical significance of this finding is uncertain. |
Menstrual Abnormalities
Menstrual changes are the rule and not the exception among women using DMPA.
Half of all women will develop amenorrhea by the end of one year's use.
Spotting and intermenstrual bleeding intermenstrual bleeding are also common.
Occasionally, this bleeding can be heavy.
These abnormalities are often simply tolerated and considered an
acceptable side-effect of this form of contraception. Alternatively, you may discontinue
the injections and allow the drug to wear off. Finally, you may treat the abnormal
bleeding with small doses of estrogen or oral contraceptive pills,but the impact on
contraception of such treatment is unknown and patients should use backup contraception
methods while BCPs or estrogen is being given.
Return of Fertility
Ovulation resumes, on average 4.5 months after the last injection. Delay
to conception after the last injection is approximately 10 months.
Weight Gain
In an uncontrolled study, 60% of women using DMPA gained weight during
the first 6 months of use. The magnitude of the weight gain was 5 pounds at the end of 1
year, and 15-16 pounds at the end of three years.
The problem with this study was the absence of a satisfactory control
group. Many BCP studies have demonstrated the trend of women, as a group, to gain weight
over time, whether they take BCPs or not.
DMPA use probably does lead to some degree of additional weight gain,
but the magnitude of this gain is uncertain.
Headaches/Breast Tenderness/Psychological
Changes
These side-effects have all been described, but are uncommon. They may
be temporary, so simply watching to see if they disappear is warranted unless the symptoms
are severe.
Among the psychological effects are diminished libido, fatigue,
depression, and nervousness. There is no way of reversing the effects of DMPA other than
letting it wear off, a process which takes 4.5 months, on the average.
Pregnancy while on DMPA
If pregnancy occurs despite the use of DMPA, there is no good evidence
that the DMPA will be harmful to the pregnancy. Because of theoretical concerns, DMPA
should not be taken if pregnancy is known or suspected.
*DEPO-PROVERA is the registered trademark of Pharmacia
& Upjohn Company, Bridgewater NJ
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