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7.3.2 Progestogen-only contraceptives

**New contraception interaction advice - see Drug Safety Update June 2011**
Oral progestogen-only contraceptives
Parenteral progestogen-only contraceptives
Medroxyprogesterone acetate (Depo-Provera) injection
Significant long-term side-effects of Depo-Provera (DMPA) include:


1. Weight gain - many women will gain up to six pounds during the first year.

2. A delay in the resumption of fertility of up to one year after cessation of use.

3. A possible reduction in bone mineral density. It is almost certainly not sufficient to cause an increased risk of fracture in pre-menopausal women. It may be sensible, however, to discontinue at the age of 45 to allow for recovery of bone mineral density before post-menopausal loss ensues.

Etonorgestrel (Nexplanon)

There have been rare reports of Nexplanon implants migrating from their initial sub-dermal insertion site, sometimes with potentially serious consequences (including the lung via the pulmonary artery). Implants that cannot be palpated  must be located - imaging should be used with a view to possible removal - see MHRA DSU. Intra-uterine progestogen-only contraceptive

Levonorgestrel (Mirena) intra-uterine system (for severe dysmenorrhoea)  
Intrauterine contraception: uterine perforation – see DSU.


Efficacy of contraceptive methods

Method failure rate
(rate/100 woman years)
User failure rate
(rate/100woman years)
COC 0.1 2-8
POP 3 10
DMPA 0.4 0.4
Mirena 0.2 0.2
Spermicides 4-28 4-28

The method failure rate (reflecting perfect use measured during clinical trials) is compared with user failure rates reflecting rates among average users who sometimes forget to use the method or make mistakes. 

It has been estimated that Levonelle-2 prevents 85% of expected pregnancies. Efficacy appears to decline with time after intercourse (95% within 24 hours, 85% 24-48 hours, 58% if used between 48 and 72 hours).


For link to BNF section: 7.3.2 Progestogen-only contraceptives