Progestogen only injection

• Overview:

  • Also known as depot medroxyprogesterone acetate (DMPA)
  • Given at 12 to 13 week intervals as IM or SC injection
  • More than 99% effective with perfect use
  • 94% effective with typical use
  • Can take 12 months for fertility to return after stopping injections
• There are two versions commonly used in the UK, all containing medroxyprogesterone acetate:

  • Depo-Provera: given by intramuscular injection
  • Sayana Press: a subcutaneous injection device that can be self-injected by the patient
• Noristerat is an alternative to the DMPA that contains norethisterone and works for eight weeks. This is usually used as a short term interim contraception (e.g. after the partner has a vasectomy) rather than a long term solution.
• Contraindications:

  • Absolute contraindication = active breast cancer
  • Risks outweigh benefits:
  • Ischaemic heart disease and stroke
  • Unexplained vaginal bleeding
  • Severe liver cirrhosis or cancer
• The DMPA can cause osteoporosis - not recommended in women under 18 or over 50

  Also consider alternative for patients on steroids
• Mechanism:

  • Main action is to inhibit ovulation - inhibiting FSH secretion by the pituitary gland - prevents development of follicles in the ovaries
  • Thickens cervical mucus
  • Alters endometrium - prevents thickening
• Timing the injection:

  • Starting on day 1-5 of the menstrual cycle offers immediate protection
  • Starting after day 5 of the menstrual cycle required 7 days of extra contraception
  • Need injections every 12-13 weeks, delaying past 13 weeks creates risk of pregnancy
• Changes to the bleeding schedule is one of the primary considerations with progestogen only contraception

  • Bleeding often becomes more irregular, and in some women it may be heavier and last longer
  • This is usually temporary
  • After a year of regular use, most women will become amenorrhoeic
• Other side effects:

  • Weight gain
  • Acne
  • Reduced libido
  • Mood changes
  • Headache
  • Flushes
  • Hair loss
  • Skin reactions at injection site
• Reduced bone mineral density (osteoporosis) is an important side effect of the depot injection. Oestrogen helps maintain bone mineral density in women, and is mainly produced by the follicles in the ovaries. Suppressing the development of follicles reduces the amount of oestrogen produced, and this can lead to decreased bone mineral density.
• The depot injection may be associated with a very small increased risk of breast and cervical cancer.
• Weight gain and osteoporosis are 2 side effects that are unique to the progestogen only injection - do not occur with other contraception
• The FSRH guidelines suggest taking the combined oral contraceptive pill (COCP) in addition to the injection for three months when problematic bleeding occurs, to help settle the bleeding. Another option is a short course (5 days) of mefenamic acid to halt the bleeding.
• There are several possible benefits of the injection, with evidence that it:

  • Improves dysmenorrhoea (painful periods)
  • Improves endometriosis-related symptoms
  • Reduces the risk of ovarian and endometrial cancer
  • Reduces the severity of sickle cell crisis in patients with sickle cell anaemia