Combined Oral Contraceptive (First Prescription)

Synonyms: COC, combined pill, 'The Pill', COCP.

This article is based on the Faculty of Family Planning and Reproductive Healthcare Guidance.¹
The combined oral contraceptive pill (COCP) is a highly effective form of contraception and used by over 17% of women aged 16 to 49 years in the UK to control fertility.²

The COCP prevents conception by acting on:

• The hypothalamic-pituitary-ovarian axis to suppress synthesis and secretion of follicle-stimulating hormone and the mid-cycle surge of luteinising hormone, thus inhibiting the development of ovarian follicles and ovulation.
• Cervical mucus to prevent penetration of sperm.
• The endometrium to inhibit blastocyst implantation.

The efficacy of any contraceptive method depends on the protection afforded by the technique itself and how consistently and correctly it is used.³

• The failure rate for the COCP when used correctly is estimated to be only 1 pregnancy per 1000 women per year. However, the typical failure rate is closer to 5 pregnancies per 100 women per year.⁴ This is favourable compared to other contraceptive methods - see: Contraception - An Overview.
• The efficacy of the COCP may be decreased by severe vomiting or diarrhoea and concurrent use of other medications.

To ensure that the woman fulfils the criteria of eligibility for use:⁵

• A full clinical history must be taken:
  • Current and previous medical conditions.
  • Drug use including prescription, over-the-counter and herbal remedies.
  • Family history.
• Specifically enquire about migraine and cardiovascular risk factors (smoking, obesity, hypertension, thrombophilia, previous venous thromboembolism - VTE and hyperlipidaemia).
• The patient's preference and individual concerns about the COCP must be addressed e.g. there is no evidence of weight gain associated with COCP use.⁶ Be mindful of ethnocultural issues.
• Record blood pressure and BMI.

The patient should be aware that:

• There is a very small increased risk of breast cancer associated with use, but this is reduced to no additional risk 10 years after stopping the pill.
• There is also a small additional risk of cervical cancer that increases with extended duration of use.

Ensure that none of the following apply to the patient:

• Women over 35 years who smoke are NOT recommended to take the COCP. There is a very small increased risk of MI with current COCP use in non-smokers, which increases further in smokers. Women over 35 years who have stopped smoking for more than 1 year may be considered for use.
• Women with a BMI over 35 have an increased risk of MI and VTE, and risks of use outweigh benefits.
• Women who have blood pressure above 140mmHg systolic and/or above 90mmHg diastolic should not use the COCP.
• Women with a personal history of VTE, or who are known to have a thrombogenic mutation should not use the COCP. A thrombophilia screen should NOT be routinely performed before prescribing. Any results should be interpreted with a haematologist.
• Women who have had migraine with aura should not use the COCP. Women aged over 35 years with migraine, but no aura, should not use the COCP.

If the patient is at risk of sexually transmitted infections, advise about continuing use of a barrier method e.g. condom for protection.

Consider whether any of the following apply to the patient:

• Liver-enzyme inducers such as carbamazepine, phenytoin and rifampicin accelerate the metabolism of oestrogen and progestogen and may reduce the efficacy of hormonal contraceptives (See Contraception and Special Groups record).
• The bioavailability of drugs such as theophylline and ciclosporin is increased by the COCP and may have toxic effects.

Advise the patient that:

• The use of short-term (<less than 3 weeks) broad-spectrum antibiotics may alter gut flora, which affects the enterohepatic circulation of oral hormonal contraceptives and reduces their efficacy. Extra precautions will be needed whilst taking the antibiotic and for 1 week after.
• Long-term, non enzyme inducing antibiotics do not require additional protection.

Take time to explain that the COCP is taken for 21 consecutive days, at approximately the same time of day (mobile phones can also act as alerts/alarms). This is followed by 7 pill-free days (or 7 days of neutral tablets) to allow endometrial shedding and a withdrawal bleed. Contraception is still provided during the hormone-free interval.¹

• Ideally the COCP should be started on the first day of menstrual bleeding, but can be started up to day 5 without the need for extra protection.
• It can be started at any other time IF THE PATIENT IS SURE SHE IS NOT PREGNANT, but additional protection e.g. condoms will be needed for the first 7 days.

Give advice on missed pills:⁷

• Advise that the leaflet in the packet contains specific recommendations, but that missing one pill, at any time does not compromise contraception.
• If vomiting occurs within 2 hours of taking the COCP, then another should be taken as soon as possible.

Extended cycling

The patient should be informed that avoidance of bleeding can be managed by extended or continuous administration of the COCP:

• It has become popular for the treatment of endometriosis, dysmenorrhoea and menstrual-associated symptoms.⁸
• Women may be given the option of 'tricycling' packets of pills to avoid menstrual periods for reasons of personal choice.
• Women are likely to report less and lighter bleeding with reduced menstrual pain and bloating.
• Similar rates of breakthrough bleeding are found with single or extended cycling.¹

Patients may also be interested in using the COCP for:

• Reduction of menstrual pain and bleeding.
• Reduction in incidence of functional ovarian cysts.
• Reduction in risk of ovarian and endometrial cancer.
• Reduction in risk of colo-rectal cancer.
• Improvement in acne vulgaris.⁹

The woman may have a particular brand she has heard of, or had recommended by family/friend. If not, or it is unsuitable consider:⁴

• A suitable first choice is a monophasic preparation with 30-35µg ethinyloestradiol and low dose norethisterone or levonorgestrel.
• A preparation with the lowest oestrogen and progestogen content, which is able to provide adequate cycle control (less breakthrough bleeding) with minimal side-effects, should be used for each individual.
• The choice of progestogen is likely to be the most important factor in cycle control and third generation pills may be considered at follow-up for those with unacceptable side-effects from other progestogens.
• Low dose oestrogen pills e.g. Loestrin®, Mercilon® and Femodette® are particularly appropriate for women with risk factors for circulatory disease, or who have a lower risk of conceiving through natural decline in fertility e.g. the mature woman.

Dianette®

Dianette® is used where acne or moderately severe hirsutism is a problem. It should be withdrawn if there is no improvement after 3 months of use. It carries a four times higher risk of VTE than other COC pills and should not be used indefinitely.

• Ideally follow-up should be after 3 months, but advise the patient to come if she becomes concerned. Provide information on signs that should prompt medical opinion e.g. new headache or VTE.
• Women should be encouraged to persist for 3 months before considering an alternative.
• Repeat blood pressure measurement and document.
• Enquire about adverse effects or problems.