Drugs.com explains that the chemical name for methylprogesterone is 17 alpha-hydroxy-6 alpha-methylprogesterone. This is more commonly known as medroxyprogesterone. Given by injection every 3 months, medroxyprogesterone prevents pregnancy by blocking follicular maturation and ovulation. Drugs.com warns that long-term use of this method of contraception should be avoided because of the severity of potential side effects.
Bone Density
Medroxyprogesterone lowers bone density. A 1991 study published in the "British Medical Journal" measured the bone density of 30 women who had been taking this drug for 5 years or more, and compared their findings to the bone density of both premenopausal and postmenopausal controls. The study found a 7.5 percent difference between the density of women taking the drug and premenopausal controls. The difference was even more pronounced when compared to postmenopausal controls. Subsequent research showed that this loss of bone density is dependent upon dose and duration of use.
Bleeding and Spotting
The American Academy of Family Physicians, or AAFP, reports that unscheduled uterine bleeding and spotting is a common side effect. The AAFP notes although this bleeding is rarely harmful, it is one of the leading reasons why women discontinue this type of contraception. The bleeding tends to diminish after the first 3 months of use. If bleeding continues to be problematic, the AAFP advises physicians to consider prescribing supplemental estrogen and a nonsteroidal anti-inflammatory drug.
Birth Defects
Drugs.com warns that this drug should never be administered during pregnancy because of the high incidence of genital abnormalities in both male and female babies. For example, the risk that the opening of the urethra will be located on the side of the newborn's penis instead of the tip is approximately doubled if the mother used medroxyprogesterone during pregnancy.
References
- "British Medical Journal": Bone Density in Women Receiving Depot Medroxyprogesterone Acetate for Contraception
- Drugs.com: Medroxyprogesterone
- UpToDate: Management of Unscheduled Bleeding in Women Using Contraception
- American Academy of Family Physicians: Abnormal Uterine Bleeding Associated with Hormonal Contraception
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