Depot contraception

Depo-Provera Injection 150mg (Medroxyprogesterone Acetate)

The major advantage of depo-provera is that the patient doesn’t have to remember to take a pill and being a progesterone only contraception, has fewer contraindications to those found with oestrogen. However, the injections usually cause a cessation of periods and a delay in return to fertility. All patients need to be counselled re benefits and risks and given a PAL to read before starting depo-provera.

Action

Inhibits ovulation, thickens cervical mucous and alters endometrium.

Advantages

Reliable with a failure rate of only 0.3%
Only needs an injection every 12 weeks.
No periods – usually.
Low risk of ectopic pregnancy and PID.
Can be considered for use if a history of migraine, hypertension (controlled), diabetes, HOWEVER IHD, DVT and cardiovascular disease assigned WHO 3 risk and a lower dose method should be considered eg implanon or Mirena IUD.
May benefit endometriosis, adenomyosis, uterine fibroids, epilepsy and sickle cell disease.
Not thought to be affected by enzyme inducing drugs.
Not known to be teratogenic, though if used in first 4 – 5 months of pregnancy may cause some masculinisation of a female foetus.

Disadvantages

Injections
Effects not reversible for duration of injection
Menstrual disturbance – amenorrhoea, spotting or heavy prolonged bleeding are all possible.
Weight gain. Vaginal dryness.
Delay in return of periods, and fertility could be delayed for up to a year.
?Some loss of bone density, though more likely in those at high risk of osteoporosis eg steroid users. Should not be considered as first line method in adolescents or over 45 yrs.

Contraindications

Pregnancy or wishes to get pregnant in near future.
Breast cancer, unresolved hydatidiform mole or active choriocarcinoma.
Liver disease.
Cardiovascular disease or BP over 160/110
Porphyria or coagulation disorders.
Undiagnosed genital tract bleeding.
Unable to tolerate menstrual disturbance.
If breast-feeding, delay for 6 weeks until well established or consider POP.
Post severe endogenous depression.
Allergy to constituent.

Administration

A deep intramuscular injection usually given into the gluteal muscle UNLESS BMI greater than 35, then give injection into the deltoid muscle. Do not massage the site after injecting.

Depo-Provera should be shaken well before the needle is attached or the air is expelled from the pre-filled syringe.
The first injection should be given within the first 5 days of menstruation; otherwise condoms need to be used for 7 days as well.
Subsequent injections should be given at 12 week intervals, except – the second injection can be given up to 4 weeks earlier to control breakthrough bleeding.
Late injections can be given without loss of effect up to 5 days late (licensed use), however research has found that repeat injections can be given up to 2 weeks late and to use condoms for a week, but consult with GP first as unlicensed use, otherwise rule 5 needs to apply.
If 1 - 2 weeks late may have repeat injection but only if pregnancy test is negative and if intercourse has taken place within 72 hours then needs emergency contraception and must use condoms for 7 days after the injection.
Over 2 weeks late then next injection has to be postponed until there has been a total of 14 days of safe contraception or abstinence since last intercourse plus a negative pregnancy test plus use of condoms for 7 days after injection.

Review

Annual BP and weight. Discuss sexual health and risk of STIs. If necessary screen for STIs. Check smear status.

Indications for stopping

No longer required – menopause, other FP method, wishes to get pregnant.
Not tolerating side effects – menstrual disturbance, weight gain.
Pregnancy
New risk factor – breast ca, acute liver disease, IHD, unacceptable risk of osteoporosis.
BP over 160/110
Age over 45?

References

Glasier,A Gebbie,A Family Planning and Reproductive Health Churchill Livingstone
Guillebaud,J Contraception Today. Taylor and Francis
www.ffprhc.org.uk