Depo-Provera is a form of contraception (also known as birth control) and is injected every three months. The injection is a brand name for medroxyprogesterone acetate. Depo-Provera is a form of hormonal contraceptive which contains a derivative of 17a-hydroxyprogesterone and the injection does not contain oestrogen. Depo-Provera is an intramuscular injection given to women every 12 weeks.
Depo-Provera works by preventing the ovaries from releasing eggs and it has a success rate of 99.7 %.
Benefits of Depo-Provera
Depo-Provera is a highly effective treatment with many advantages, which include:
- Very high success rate for preventing pregnancy (99.7 %).
- One injection required every 12 weeks; there is no need to remember to take a pill every day as all patients have to do is remember to arrange appointments to have the injection every 3 months.
- No oestrogen decreases the threat of deep vein thrombosis (DVT), strokes, heart attack (myocardial infarction) and pulmonary embolism.
- Cultural benefits: some cultures believe that injections are more acceptable than other forms of treatment.
- Privacy: the injection is given by a doctor in the privacy of a treatment room and its use cannot be detected by other people.
- Fewer drug interactions: the injection has fewer drug interactions than other types of contraceptive and is therefore suitable for most people who are already taking medication.
- Decreased threat of endometrial cancer: studies suggest that Depo-Provera can lessen the threat of endometrial cancer by up to 80 percent; this is believed to be the result of progestogen on the lining of the womb and the reduced levels of oestrogen, which is caused by the prevention of the release of eggs by the ovaries.
- Reduced symptoms of endometriosis.
- Reduced risk of PID (pelvic inflammatory disease), uterine fibroids, iron deficiency anaemia and ectopic pregnancy.
- Reduced prevalence of ovarian pain, heavy periods (primary dysmenorrhoea) and ovarian cysts.
- Reduced frequency of seizures in females with epilepsy; this is because Depo-Provera is not influenced by enzyme-inducing anti-epileptic medications.
- Reduced symptoms in females with sickle cell anaemia.
- Depo-Provera can take up to 14 days to be effective and therefore it is important to use additional forms of contraception to prevent pregnancy during the first fortnight.
- If the injection is given after the initial 4 days of the menstrual cycle it can take up to 7 days to be effective; if the injection is administered during the first 4 days it will take effect immediately.
- Depo-Provera does not offer defence against sexually transmitted infections.
- Depo-Provera can affect the menstrual cycle; research suggests that after one year of use 55% of females experience amenorrhoea (the absence of menstrual bleeding) and this figure increases to 68% after two years. It is common for women to experience irregular bleeding and spotting during the first few months of use.
- Depo-Provera reduces fertility for a period of time after the user stops having injections; it can take up to ten months for fertility rates to return and up to 18 months for fertility to return to normal levels (similar to women who have used other forms of contraception).
- Studies suggest little to no increased threat of breast cancer; however, recent research suggests that there is a slightly elevated risk for women aged less than 35 who have recently started using the injection; the increased risk is similar to that associated with taking the oral contraceptive pill.
- Babies that were born to women who used Depo-Provera during pregnancy are more likely to die within the first 12 months; studies show that the risk is 80 percent higher in babies exposed to the injection during pregnancy.
- Depo-Provera increases the risk of bone loss and the risk increases the longer the injection is used; the risk is likely to stay the same even after the woman has stopped using the injection.
Clinical trials revealed the following side-effects:
- Irregular menstrual bleeding
- Irregular periods
- Feeling anxious or nervous
- Changes in weight
- Abdominal pain
- Feeling weak and tired
Patients with certain health conditions may be advised against using Depo-Provera as a form of contraception. In the following cases it is believed that the risks outweigh the benefits of using Depo-Provera:
- Pulmonary embolism (PE) or Deep vein thrombosis (DVT)
- Several threats for arterial cardiovascular disease
- Migraines with aura symptoms (when using Depo-Provera)
- Unexplained vaginal bleeding
- Predisposition to breast cancer
- Liver disease (including conditions such as cirrhosis, acute viral hepatitis and liver tumours, which may be benign or malignant)
- Breast cancer (either current or recurrent)
- Conditions which may be affected by lower levels of oestrogen and HDL, such as a history of strokes, ischemic heart disease, high blood pressure, vascular disease and diabetes.