Synonyms: POP, mini-pill
Approximately 5% of women aged 16-49 years in the UK use the progestogen-only contraceptive pill (POCP). It is particularly used when combined hormonal contraception is contra-indicated, eg breast-feeding mothers.
Levonelle® is progestogen-only emergency contraception.
Mode of action
- Ovulation is inhibited in about 60% of cycles (although it does not occur in 100% of cycles normally). With desogestrel, ovulation is inhibited in 97% of cycles.
- Transport of the ovum is delayed.
- The cervical mucus becomes more viscous and impenetrable to sperm.
- The endometrium becomes unsuitable for implantation.
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Advantages of a progestogen-only contraceptive pill compared with a combined oral contraceptive pill
- It is an effective and safe form of contraception and is often used when oestrogens are contra-indicated - eg venous thromboembolism, past history of it or tendency to venous thromboembolism, or migraine with aura.
- It contains an even lower dose of progestogen than low-dose combined contraceptives and no oestrogen.
- It is a suitable alternative for those aged over 35 who need to be changed from a COCP, heavy smokers, those with hypertension, valvular heart disease, diabetes mellitus, migraine. There are, however, very little data on cardiovascular risk and the progestogen-only contraceptive pill (POCP).
- It can be used during breast-feeding.
- It is suitable for women with valvular heart disease and those about to undergo major surgery or surgery on their legs.
- It is suitable for those who want a minimal dose of hormone, as it gives a very low dose.
- It is no less effective in women weighing over 70 kg.
Disadvantages of a progestogen-only contraceptive pill (compared with a combined oral contraceptive pill)
- It has to be taken meticulously at the same time each day. The error for forgotten pills is just 3 hours late for progestogen-only contraceptive pills (POCPs), with the exception of Cerazette®, which has a licence for 12 hours.
- It is just as susceptible to substances that cause enzyme induction, like rifampicin, many anticonvulsants and St John's wort. It is not affected by broad-spectrum antibiotics.
- It does not give the regulation of menstruation like the combined oral contraceptive pill (COCP) - including its tendency to alleviate symptoms of premenstrual tension, dysmenorrhoea and making menstruation lighter:
- It may produce irregular menstruation or amenorrhoea. This may be trouble enough for some to lead to cessation of the method.
- If oestrogen levels fall and cause amenorrhoea there may be concern that there is a risk of osteoporosis:
- This has been studied more in relation to depot and implant contraception. An overview of the relationship between use of POCPs and bone mineral density found little evidence about this in users of the POCP, but the study involved only a small number of lactating women.
- There is an increased risk of ovarian cysts, perhaps up to 30%. They are usually reversible and do not require operation.
- The data on the risk of breast cancer with POCP users do not suggest a causal link. However, large randomised controlled trials are still needed to confirm this.
- The progestogen-only contraceptive pill (POCP) must not be used in the presence of breast cancer as this is a hormone-dependent tumour. It may be considered if there has been no evidence of disease for five years if other methods do not seem acceptable.
- The risk of thromboembolism is much less than with the combined oral contraceptive pill (COCP) but, in the presence of DVT or pulmonary embolism, it should be avoided.
- There is concern about reduction in the levels of high-density lipoprotein (HDL), although this may be less marked with the newer progestogens. Hence, they are better avoided in established coronary heart disease (CHD) or stroke.
- As with any other form of hormonal contraception, it should be avoided in liver disease.
Instructions for use
- It is usually started on the first day of menstruation and then no additional contraceptive is required.
- After childbirth it can be started on day 21, irrespective of whether the woman is breast-feeding. There is no need for contraception before then. There is a theoretical risk of intermenstrual bleeding if started earlier but the guidelines suggest that, if the woman requests earlier contraception, this can be offered.
- It can be started immediately after termination of pregnancy in any trimester and it is immediately effective.
- If changing from a combined oral contraceptive pill (COCP) to a progestogen-only contraceptive pill (POCP), start at the end of a COCP pack, moving straight on from the last COCP to the POCP the following day. If the COCP is an every day (ED) pack then start after the last active pill.
- Pills must be taken at about the same time each day. It is regarded as late if it is taken more than 3 hours after the usual time or 12 hours with Cerazette®. The missed pill should be taken as soon as possible. The subsequent pills should be taken as usual but additional contraception should be used until pills have been taken correctly for two days.
- Vomiting or severe diarrhoea may impair absorption of the hormone. Additional contraception should be used during this phase and for two days afterwards.
- Women using the POCP should be advised that the efficacy of these methods may be reduced by enzyme-inducing drugs and that they should use an alternative method. Women using the POCP with a short-term course of enzyme-inducing drug (≤2 months) could be offered a one-off injection of depot medroxyprogesterone acetate (DMPA).
- Women should be advised that there is no evidence of reduced efficacy with non-liver enzyme-inducing antibiotics and additional contraceptive protection is not required.
- Irregular menstrual pattern may settle with time or a change to a different formulation.
Desogestrel is a newer progestogen that is converted in the body to the active form of etonogestrel. The only contraceptive pill containing desogestrel, currently licensed in the UK, is Cerazette®. The feature of this formulation that is likely to have the greatest impact is the 12-hour window for 'forgetfulness' rather than just 3 hours.
Amenorrhoea is more likely to occur than with levonorgestrel use - approximately 40% of users. The overall failure rate for the desogestrel-only pill has been found to be 0.41 per 100 woman-years. There are insufficient data to compare types of POCP to each other.
Further reading & references
- Contraceptive Medical Eligibility Criteria, World Health Organization
- No authors listed; Is Cerazette the minipill of choice? Drug Ther Bull. 2003 Sep;41(9):68-9.
- Milsom I, Korver T; Ovulation incidence with oral contraceptives: a literature review. J Fam Plann Reprod Health Care. 2008 Oct;34(4):237-46.
- Progestogen-only Pills, Faculty of Sexual and Reproductive Healthcare (2009)
- Banks E, Berrington A, Casabonne D; Overview of the relationship between use of progestogen-only contraceptives and bone mineral density.; BJOG. 2001 Dec;108(12):1214-21.
- Sitruk-Ware R; New progestogens: a review of their effects in perimenopausal and postmenopausal Drugs Aging. 2004;21(13):865-83.
- Contraceptive choices for breastfeeding women, National Guideline Clearing House 2008
- Missed Pill Recommendations, Faculty of Sexual and Reproductive Healthcare (2011)
- Drug Interactions with Hormonal Contraception, Faculty of Sexual and Reproductive Healthcare (2011)
- Cerazette®; Cerazette®, New Product Review, Faculty of Family Planning and Reproductive Health Care (2003)
- Summary of Product Characteristics (SPC) - Cerazette® 75 microgram film-coated tablet; Merck Sharp & Dohme Limited, electronic Medicines Compendium. December 2011.
- Ray S, Sovani VB; A postmarketing observational study assessing acceptability and reliability of J Indian Med Assoc. 2006 Nov;104(11):653-6.
- Grimes DA, Lopez LM, O'Brien PA, et al; Grimes DA, Lopez LM, O'Brien PA, et al; Progestin-only pills for contraception. Cochrane Database Syst Rev. 2010 Jan 20;(1):CD007541.
|Original Author: Dr Laurence Knott||Current Version: Dr Hayley Willacy||Peer Reviewer: Dr Hannah Gronow|
|Last Checked: 19/10/2011||Document ID: 471 Version: 5||© EMIS|
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