Combined oral contraceptive pill

Good practice for the first prescription of the combined oral contraceptive (COC) pill is described in the separate article Combined Oral Contraceptive Pill (First Prescription). This article covers good practice for follow-up, safe ongoing prescribing and issues which may be encountered in doing so.

When to follow up

After the first prescription, review at three months. If all is well, follow up at 6- to 12-monthly intervals. Supplies of up to a year may be issued.

Stress to the woman that she should return earlier if she develops any problems or side-effects, or if she has any concerns.

What to do in the follow-up consultation

• Ask:
  

  • Has she found it easy to use/remember?

  • Has she noticed any adverse effects?

  • Does she understand how to take it?

  • Does she know how to manage missed pills?

  • Has the pattern of withdrawal bleeds been regular?

  • Has there been any breakthrough bleeding (BTB)?

  • Have there been developments in her medical history (eg, new medication) or social history (eg, age and smoking) which need to be considered.

• Examination:
  

  • Check blood pressure.

  • Measure body mass index (BMI)

• Consider whether contraception is still required and if the combined pill is still the most appropriate and the safest method.

• Check whether cervical screening is due.

• Give the patient the opportunity to ask questions

Common problems

Breakthrough bleeding (BTB)

See the separate article Breakthrough Bleeding with Combined Hormonal Contraception. Women should be advised that this can occur with the COC pill, most commonly in the first few months. If there has been no vomiting or diarrhoea and there have been no missed pills, it has not been shown to indicate reduced efficacy. Consider sexually transmitted infections, pregnancy, missed pills, and malabsorption as possible causes, but BTB is a common side-effect.

Weight gain

Cochrane reviews have consistently failed to show any evidence that significant weight gain is a side-effect of the pill¹ .

Interactions

There are many commonly used medications which can affect the efficacy of the pill:

• Antibacterials - enzyme inducers only (eg, rifampicin, rifabutin).

• Antidepressants - St John's wort (which can be bought over the counter).

• Anticonvulsants - carbamazepine, oxcarbazepine, eslicarbazepine, phenobarbital, phenytoin, primidone and topiramate, due to their enzyme-inducing activity. Also lamotrigine which has a specific safety warning - there is an increased risk of seizure whilst taking the COC pill with lamotrigine, and a risk of toxicity during the pill-free week, when levels rise. Therefore, risk may outweigh benefit (UKMEC category 3).

• Antiretrovirals - in particular, ritonavir-boosted protease inhibitors.

• Ulipristal acetate (the 'morning after pill' ellaOne®).

Women on medication which may interact with the contraceptive pill should be advised to carry out a pregnancy test and seek medical advice if there is a very light or no withdrawal bleed. They should also seek advice if they have BTB, which may indicate reduced efficacy in this situation.

Other medications may cause lack of efficacy of the contraceptive pill by causing side-effects such as diarrhoea or vomiting. Women on the anti-obesity pill orlistat who experience severe diarrhoea, for example, are advised to use additional contraceptive precautions as there is a theoretical risk of lack of absorption.

Concomitant administration of the COC pill with some medications may increase levels. This may be the case with theophylline, and levels should be monitored. Tacrolimus levels may also be increased, and effect should be monitored.

Diarrhoea and vomiting

• Vomiting within two hours of taking the pill, or very severe diarrhoea, can affect the absorption of the pill.

• The advice for women who experience vomiting or diarrhoea for more than 24 hours is to follow the same advice as if they had missed pills.

Surgery

For any woman on the COC pill about to undergo a major elective operation, the risk of thromboembolism needs to be balanced with the risk of unwanted pregnancy. Usually the COC pill would be discontinued four weeks before elective major surgery and restarted on day one of the next period, occurring at least two weeks after mobilisation² . Progestogen-only contraception can be offered as an alternative during this time.

Women requiring emergency surgery should receive subcutaneous heparin and compression stockings.

This does not apply to women having minor surgery where there are short periods of anaesthesia, such as tooth extractions or laparoscopic sterilisation.

Amenorrhoea

• There can be amenorrhoea following cessation of using the COC pill. This is usually due to the pill's withdrawal bleeds masking an underlying problem.

• Any amenorrhoea lasting more than six months after stopping the pill should be investigated as for secondary amenorrhoea.
  

Mature women

This is detailed in the separate Contraception from 40 to the Menopause article.

Other uses for the combined hormonal contraceptive pill

Menorrhagia and dysmenorrhoea

• In women with heavy and/or painful menses the COC pill has been shown to be beneficial. There is evidence for its efficacy in reducing menorrhagia, similar to mefenamic acid³ . There is weak evidence for its efficacy for primary treatment of dysmenorrhoea⁴ . There is no evidence for benefit of one type of COC pill being better than any other.

• It can also make the cycle more manageable by running packs together, and in avoiding the pill-free week, women can avoid the withdrawal bleed. This is particularly useful for travel, but also for athletes. It is good practice to advise women that they can manipulate their cycle in this way.

Polycystic ovary syndrome (PCOS)⁵

• Women who have PCOS are often oligo-amenorrhoeic.

• Endometrial cystic hyperplasia is associated with prolonged periods of anovulation, as found in PCOS.

• There is an association between PCOS and endometrial hyperplasia and carcinoma. They should be offered protective therapy from prolonged exposure to relatively unopposed oestrogen. The COC pill does this effectively, as well as providing contraception. However, cardiovascular risks should be taken into account, as women with PCOS are also at risk of the metabolic syndrome, and may be more likely to be overweight.

• The COC pill may be superior to metformin for controlling hormonal effects of PCOS (eg, hirsutism), but evidence reviewed is generally low in quality⁶ .

Acne⁷

• Randomised controlled trials have shown significant improvements in acne vulgaris whilst using the COC pill.

• This evidence is specific for preparations containing the progestogens levonorgestrel and norethisterone. There is no consistent evidence to support the use of any particular pill as being more effective than another for this purpose.

• Dianette® is also indicated for use in acne or moderately severe hirsutism. It should be withdrawn if there is no improvement after three months of use. Dianette® carries a 50-80% greater risk of venous thromboembolism (VTE) than COC pills containing levonorgestrel, but no higher than those containing gestodene, desogestrel, or drospirenone with 30-35 micrograms of ethinylestradiol⁸ .

Reducing the risk of cancer

• The pill has been shown to reduce the risk of ovarian, endometrial, and colorectal cancer, and lymphatic and haematopoietic cancer⁹ .

• The risk reduction is most significant for ovarian cancer. For every five years of use, there is a 20% reduction in the risk of ovarian cancer, and after 15 years of use a woman's risk is half that of a woman who has never taken the pill¹⁰ .

• There is currently insufficient evidence for the use of the COC pill for the primary prevention of ovarian cancer. Modelling suggests that BRCA mutation carriers should consider using the oral contraceptive pill for chemoprevention¹¹ .

• An increased risk of breast cancer seen in current and recent users seems to be lost within approximately five years of stopping oral contraception, with no evidence of increased risk in 'ever' users with time⁹ . For BRCA1 and BRCA2 mutation carriers, the association between COC pill use and breast cancer risk is still unclear, so indications other than contraception should be avoided and non-hormonal contraceptive methods should be discussed¹² .