Progestogen-only injectable contraception

Depo-Provera is an injectable contraceptive containing medroxy progesterone acetate. It is licensed for long and short term use.

Provided that it is reasonably certain that the woman is not pregnant, the use of injectable contraceptives may be started:

• up to and including the fifth day of the menstrual cycle without the need for additional contraceptive protection
• at any other time in the menstrual cycle, but additional barrier contraception should be used for the first 7 days after the injection
• immediately after first- or second-trimester abortion, or at any time thereafter
• at any time post-partum

Contraceptive efficacy

• progestogen-only injectable contraceptives act primarily by preventing ovulation (1,2)
• pregnancy rate associated with injectable contraceptives, when given at the recommended intervals, is very low (fewer than 4 in 1000 over 2 years) and the pregnancy rate with Depo medroxyprogesterone acetate (DMPA) is lower than that with norethisterone enantate (NET-EN)
• DMPA should be repeated every 12 weeks and NET-EN every 8 weeks
  • an injection of DMPA can be administered up to 7 days late (up to 14 weeks after the last injection) without the need for additional contraceptive precautions (outside the product licence for IM DMPA). If necessary, an early repeat injection of DMPA can be administered from 10 weeks and from 6 weeks for norethisterone enantate (NET-EN)(outside product licence) (3)
• may be a delay of up to 1 year in the return of fertility after stopping the use of injectable contraceptives
  • if a woman stops using injectable contraceptives but does not wish to conceive, she should start using a different contraceptive method immediately even if amenorrhoea persists

Administration: intramuscular (IM) medroxyprogesterone acetate (DMPA) injection

• gluteal muscle in the buttock is the preferred site for IM DMPA administration but it can be administered into the deltoid muscle of the upper arm. In women with deep adipose tissue in the gluteal area, standard-length needles may not reach the muscle layer and SC DMPA or deltoid administration of IM DMPA should be considered (3)

Dose and frequency of administration (4)

• Single IM injection (150mg/1ml) on day 1-5 of the menstrual cycle with no need for additional protection.
• IM DMPA can be started at any time after day 5 if it is reasonably certain that the individual is not pregnant. Additional precautions are then required for 7 days after starting and advise to have follow up pregnancy test at 21 days if there was a risk of pregnancy
• When starting or restarting IM DMPA as quick start after levonorgestrel emergency contraception, additional contraception is required for 7 days and follow up pregnancy test at 21 days is required.
• In line with FSRH guidance, individuals should delay starting or restarting hormonal contraception for 5 days following use of ulipristal acetate for emergency contraception. Avoidance of pregnancy risk (i.e. use of condoms or abstain from intercourse) should be advised for a further 7 days and follow up pregnancy test at 21 days is required.
• IM DMPA dose should be repeated 13 weeks after the last injection.
• If required a repeat injection can be given up to 14 weeks after the previous dose with no additional contraceptive precautions.
• If required on an occasional basis, IM DMPA injection may be repeated as early as 10 weeks after the last injection.
• If the interval from the preceding injection is greater than 14 weeks the injection may be administered/supplied - the professional administering the injection should refer to FSRH current guidelines for advice on the need for additional contraception and pregnancy testing.

Administration: subcutaneous medroxyprogesterone acetate (SC-DMPA) injection (5)

Dose and frequency of administration (5)

• Single pre-filled injection (104mg/0.5ml) on day 1-5 of the menstrual cycle with no need for additional protection
• SC-DMPA can be started at any time after day 5 if it is reasonably certain that the individual is not pregnant. Additional precautions are then required for 7 days after starting and advise to have follow up pregnancy test at 21 days if there was a risk of pregnancy
• When starting or restarting SC-DMPA as quick start after levonorgestrel emergency contraception, additional contraception is required for 7 days and follow up pregnancy test at 21 days is required.
• In line with FSRH guidance individuals should delay starting or restarting hormonal contraception for 5 days following use of ulipristal acetate for emergency contraception. Avoidance of pregnancy risk (i.e. use of condoms or abstain from intercourse) should be advised for a further 7 days and follow up pregnancy test at 21 days is required.
• SC-DMPA dose should be repeated 13 weeks after the last injection.
• If required a repeat injection can be given up to 14 weeks after the previous dose with no additional contraceptive precautions.
• If required on an occasional basis, SC-DMPA injection may be repeated as early as 10 weeks after the last injection.
• If the interval from the preceding injection is greater than 14 weeks and unprotected sexual intercourse (UPSI) has occurred the injection may be administered/supplied - the professional administering the injection should refer to FSRH current guidelines for advice on the need for additional contraception and pregnancy testing.

For guidance on changing from one contraceptive method to another, and when to start after an abortion and postpartum, refer to the Faculty of Sexual and Reproductive Healthcare (FSRH) guidelines.

Risks and possible side effects

• DMPA use may be associated with an increase of up to 2-3 kg in weight over 1 year
  • use of DMPA appears to be associated with weight gain, particularly in women under 18 years of age with a body mass index (BMI) >30 kg/m2 (3)
  • women who gain more than 5% of their baseline body weight in the first 6 months of DMPA use are likely to experience continued weight gain (3)
• DMPA use is not associated with acne, depression or headaches
• DMPA use is associated with a small loss of bone mineral density, which is largely recovered when DMPA is discontinued
• no evidence that DMPA use increases the risk of fracture
• there is a weak association between cervical cancer and use of DMPA for 5 years or longer. Any increased risk appears to reduce with time after stopping and could be due to confounding factors (3)
  
• Ulipristal acetate (UPA) has the potential to reduce the efficacy of hormonal contraception. For women using the progestogen-only injectable, additional precautions are advised for 14 days after taking UPA for emergency contraception (outside product licence) (3)
• unscheduled bleeding - assess unscheduled bleeding as per linked item then (3):
  • women who experience unscheduled bleeding during use of a progestogen-only injectable and who are medically eligible can be offered a combined oral contraceptive (COC) for 3 months. This can be taken in the usual cyclic manner or continuously without a hormone-free interval (outside product licence). Longer-term use of the injectable and COC has not been studied and is a matter of clinical judgement (3)
  • women with unscheduled bleeding during use of a progestogen-only injectable contraceptive can be offered 500 mg mefenamic acid up to three times daily for 5 days

Possible additional benefits:

• DMPA is a contraceptive option for women with sickle cell disease and may reduce the severity of sickle crisis pain (3)
• amenorrhoea or reduced bleeding is common in progestogen-only injectable users and may benefit women with menstrual problems (3)

Before prescribing, check the Summary of Product Characteristics of any of the drugs mentioned.

Reference:

1. BNF 7.3
2. NICE (September 2014). Long-acting reversible contraception
3. FSRH (December 2014). Progestogen-only injection contraception.
4. Patient Group Direction (PGD) (NHS Specialist Pharmacy Service).Administration of intramuscular (IM) medroxyprogesterone acetate (DMPA) injection . (Accessed 17th March 2021).
5. Patient Group Direction (PGD) (NHS Specialist Pharmacy Service).Supply and/or administration of subcutaneous medroxyprogesterone acetate (SC-DMPA) injection . (Accessed 17th March 2021).