The basics - Prescribing oral contraception

Check competence and contraindications before prescribing the COCP.

Note BP, BMI and smoking status
Note BP, BMI and smoking status

Before prescribing any contraception, the patient's competency should be considered.

An adult is competent if they can understand and retain information and use that information to make an informed decision.

If the patient is under 16, the law states contraception advice and treatment can only be provided without parental consent if Fraser guidelines are met.

These criteria ensure that the girl understands the information given, even if she cannot be persuaded to inform her parents or allow a healthcare professional to inform them, that she is likely to continue to have sex with or without contraception, that her physical or mental health will suffer if contraception is withheld, and that it is in her best interests to provide contraceptive advice without parental consent.

Questions to ask
Ask and document age, medical conditions, medications and family history. Ask about problems that may contraindicate the use of combined oral contraceptive pills (COCP) using the UK Medical Eligibility Criteria (UKMEC). UKMEC categories three and four rule out a COCP's use in primary care.

Enquire about a history of VTE or migraine with aura. A family history of DVT in a first-degree relative under 45 or BRCA1-positive breast cancer is a contraindication.

Note the BP, BMI and smoking status. The COCP is a UKMEC category three or four if the patient is known to be hypertensive (BP is ≥140/90), if BMI is ≥35, or if the patient is over 35 and smokes or stopped smoking less than one year ago. In the above circumstances all other contraceptive methods are indicated.

How to start
First line is a monophasic preparation containing 30 micrograms of estrogen plus either norethisterone or levonorgestrel.

The COCP is taken in a 28-day cycle. An active pill is taken daily for 21 days followed by a seven-day pill-free interval, during which the reduction in estrogen and progesterone causes a withdrawal bleed. Ideally start on day one-five of menses for immediate contraception.

The pill can be started at other times of the cycle but first exclude pregnancy and inform the patient they will require additional protection for the first seven days of taking the pill.

If the patient is already using another COCP, patch or progesterone-only pill, start the new COCP straight away or at the end of the current packet, omitting the pill-free interval, for immediate contraception.

If the COCP is being used after depot injection, it should be started when the repeat injection would have been given.

If the patient had used an IUD, immediate contraception is provided if the COCP is started on days one-five of menstruation.

Missed pills
A missed pill is when one is taken more than 24 hours later than the usual time. In all cases, take the last missed pill immediately and continue with the current packet as usual. If a pill is missed in week three, advise to complete the current pack and immediately start a new packet, omitting the pill-free interval. If greater than seven pills are missed, advise to recommence as if the pill had never been used.

The riskiest time to miss a pill is within the first seven days when ovulation has not yet been inhibited, or if the missed pill extends the pill-free interval beyond seven days. fpa (formerly The Family Planning Association) regards loss of contraception when either two or more 20-microgram pills are missed (two for 20) or three or more 30 - 35 microgram pills are missed (three for 30).

If contraceptive protection is reduced, use extra protection until seven consecutive pills have been taken.

Interactions
If patients are on antibiotics or have diarrhoea and vomiting for more than 24 hours, advise extra precaution during and then for seven days afterwards.

If this extends into the last seven pills of a packet, omit the pill-free interval and commence a new packet immediately. COCPs also interact with certain medications. Check UKMEC if new medications are commenced.

Other information
Warn that the COCP can initially cause unscheduled bleeding so encourage its use for three months before considering an alternative. Remind the patient its use does not protect against STIs and condoms must be advised.

Explain the COCP carries risks of blood clots so seek immediate medical help if they experience any chest pain, calf pain or problems breathing. Arrange a review for in three months.

  • Dr Taylor-Walker is a GP locum in Leicestershire
  • Contraception Awareness Week is 8-14 February 2010
Key points
  • Assess competency.
  • Rule out contraindications using UKMEC.
  • Record BP and BMI.
  • Discuss the method and inform how to use.
  • Give written and verbal advice regarding missed pills, new medications, antibiotics, diarrhoea and vomiting.

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