COCP

• Overview:

  • Combined oral contraceptive pill contains a combination of oestrogen and progesterone
  • More than 99% effective with perfect
  • 91% effective with typical use
  • Licensed for use up to the age of 50
• The COCP prevents pregnancy in three ways:

  • Preventing ovulation (this is the primary mechanism of action)
  • Progesterone thickens the cervical mucus
  • Progesterone inhibits proliferation of the endometrium, reducing the chance of successful implantation
• preventing ovulation:

  • Oestrogen and progesterone have a negative feedback effect on the hypothalamus and anterior pituitary
  • Suppresses the release of GnRH, LH and FSH
  • Without the effects of LH and FSH, ovulation does not occur - pregnancy cannot occur
• The lining of the endometrium is maintained in a stable state while taking the combined pill. When the pill is stopped the lining of the uterus breaks down and sheds. This leads to a “withdrawal bleed“
• There are two types of COCP to be aware of:

  • Monophasic pills contain the same amount of hormone in each pill
  • Multiphasic pills contain varying amounts of hormone to match the normal cyclical hormonal changes more closely
• Different formulations vary in the amount of oestrogen (ethinylestradiol) and the type of progesterone they contain. Examples of monophasic combined contraceptive pills are:

  • Microgynon contains ethinylestradiol and levonorgestrel
  • Loestrin contains ethinylestradiol and norethisterone
  • Cilest contains ethinylestradiol and norgestimate
  • Yasmin contains ethinylestradiol and drospirenone
  • Marvelon contains ethinylestradiol and desogestrel
• Pills with levonorgestrel or norethisterone (e.g. Microgynon or Leostrin) should be used first line as these choices have a lower risk of VTE
• Pills containing drospirenone:

  • Yasmin
  • First line for PMS
  • Drospirenone has anti-mineralocorticoid and anti-androgen activity which may help with symptoms of bloating, water retention and mood changes
  • Continuous use instead of cyclical use may be more effective for PMS
• Dianette:

  • Contains cyproterone acetate
  • Treatment of acne and hirsutism
  • Has anti-androgen effects
  • The oestrogenic effects mean it has a 1.5-2 times greater risk of VTE compared to first line choices
  • Usually stopped three months after acne is controlled due to VTE risk
• The combined pill can be taken in different regimes to suit the individual. These regimes are equally safe and effective. Three common options are:

  • 21 days on and 7 days off
  • 63 days on (three packs) and 7 days off (“tricycling“)
  • Continuous use without a pill-free period
• Side effects and risks:

  • Unscheduled bleeding is common in the first three months and should then settle with time
  • Breast pain and tenderness
  • Mood changes and depression
  • Headaches
  • Hypertension
  • Venous thromboembolism (the risk is much lower for the pill than pregnancy)
  • Small increased risk of breast and cervical cancer, returning to normal ten years after stopping
  • Small increased risk of myocardial infarction and stroke
• The benefits of the combined pill include:

  • Effective contraception
  • Rapid return of fertility after stopping
  • Improvement in premenstrual symptoms, menorrhagia (heavy periods) and dysmenorrhoea (painful periods)
  • Reduced risk of endometrial, ovarian and colon cancer
  • Reduced risk of benign ovarian cysts
• Contraindications:

  • Uncontrolled hypertension (particularly ≥160 / ≥100)
  • Migraine with aura (risk of stroke)
  • History of VTE
  • Aged over 35 and smoking more than 15 cigarettes per day
  • Major surgery with prolonged immobility
  • Vascular disease or stroke
  • Ischaemic heart disease, cardiomyopathy or atrial fibrillation
  • Liver cirrhosis and liver tumours
  • Systemic lupus erythematosus (SLE) and antiphospholipid syndrome
• It is worth noting that a BMI above 35 is UKMEC 3 for the combined pill (risks generally outweigh the benefits).
• Starting the pill:

  • No additional contraception is required if the pill is started before day 5 of the menstrual cycle
  • If started after day 5 of cycle, extra contraception is required for 7 days
  • Ensure not pregnant prior to starting
  • When switching between COCPs, finish one pack and then immediately start the new pill pack without the pill-free period
• Missed pills:

  • Missing one pill is when the pill is more than 24 hours late
  • 48 hours since the last pill was taken
• Missing one pill (less than 72 hours since the last pill was taken):

  • Take the missed pill as soon as possible (even if this means taking two pills on the same day)
  • No extra protection is required provided other pills before and after are taken correctly
• Missing more than one pill (more than 72 hours since the last pill was taken):

  • Take the most recent missed pill as soon as possible (even if this means taking two pills on the same day)
  • Additional contraception (i.e. condoms) is needed until they have taken the pill regularly for 7 days straight
  • If day 1 – 7 of the packet they need emergency contraception if they have had unprotected sex
• Vomiting, diarrhoea and certain medications (e.g. rifampicin) can all reduce the effectiveness of the pill, and additional contraception may be required. A day of vomiting or diarrhoea is classed as a “missed pill” day, as the illness may affect the absorption.
• The COCP should be stopped 4 weeks before a major operation or any procedure that required the lower limb to be immobilised - to reduce risk of thrombosis