Depo-Provera is used to prevent pregnancy in women. It is administered every 12 weeks and prevents pregnancy by preventing ovulation, increasing the natural mucus at the neck of the womb and making the lining of the womb unprepared for implantation. Depo-Provera contains medroxyprogesterone acetate, a synthetic form of progesterone. At high doses, Depo-Provera can be used to treat cancers. Because it alters a woman's hormones, long-term Depo-Provera use can cause significant side effects.
Bone Loss
Depo-Provera causes a reduced level of estrogen, which in turn causes bone to be reabsorbed over bone formation. The November 2006 issue of "Fertility and Sterility" published a study which showed that women on Depo-Provera had up to 7.7 percent bone loss. The same study showed that though this bone loss is reversible after 18 months of stopping Depo-Provera, bone loss still had not returned to control levels.
Bleeding Irregularities and Fertility
Depo-Provera can stop menstrual bleeding, a condition called amenorrhoea, in over half of women who have been on the drug for 12 months, according to a study published in the March 1996 issue of the "International Journal of Fertility and Menopausal Studies." Over 60 percent of women studied who were on Depo-Provera for longer than 12 months had amenorrhoea. Other patients may experience irregular bleeding or spotting while using Depo-Provera as a contraceptive. Depo-Provera has also been linked to infertility after stopping using the drug, though this was found not to be permanent in the 1996 study.
Cancer Risks
A number of contraceptives have been linked to an increase in the risk of developing cancer. Depo-Provera has been found to have no overall increased risk of ovarian, breast, liver or cervical cancer. However, women starting Depo-Provera under the age of 35 years did show a small significant increase risk of developing breast cancer. A review published in September 1996 in the journal "Drug Safety" showed that the risk of breast cancer declined with time since the last use of Depo-Provera. Women who had not used Depo-Provera for over 5 years but who had previously used Depo-Provera for 2 years actually showed a reduced risk of developing breast cancer.
References
- "Fertility Sterility"; Bone mineral density loss and recovery during 48 months in first-time users of depot medroxyprogesterone acetate; M.K. Clark, et al.; November 2006
- "International Journal of Fertility and Menopausal Studies"; Long-active Contraceptive Options; A.M. Kaunitz; March 1996
- "Drug Safety"; Depot Medroxyprogesterone Acetate and Breast Cancer. A Review of Current Knowledge; C.E. Chilvers; September 1996
