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Community pharmacists are increasingly seen as advocates for women’s reproductive health in Ireland. Since 2018, community pharmacists have been providing emergency contraception directly to patients without a prescription. The introduction of the free contraception service in 2022 by the Department of Health, has been a welcome initiative, enabling greater access to contraception for women aged 17 to 35 years of age.
Combined hormonal contraception (CHC) is one of the most popular methods of contraception used in Ireland. CHC can be administered in oral form (combined oral contraception, known as ‘the pill’), as a transdermal patch or a vaginal ring. CHC contains a combination of an oestrogen and a progestogen and it primarily works as a contraceptive by preventing ovulation. It is considered suitable to prescribe CHC for up to one year at a time, according to the Faculty of Sexual and Reproductive Health (FSRH).
The United Nations report that 65 per cent of Irish women use a form of contraception and a survey in 2020 commissioned by the Dublin Well Woman Centre found that 73 per cent of respondents had used the contraceptive pill at some point (no distinction was made between the combined oral contraceptive pill and the progestogen only pill). A much smaller percentage used the contraceptive patch (6 per cent) or the vaginal ring (5 per cent). Therefore, CHC is a medicine commonly dispensed in community pharmacies.
CHC has many benefits for patients including being a convenient and effective form of contraception. If used ‘perfectly’, CHC has a very low rate of failure and results in an unintended pregnancy in 0.3 per cent of users. However, the rate of unplanned pregnancies which result from typical use of CHC is estimated at 9 per cent. As well as this, there is a quick return to fertility upon stopping CHC. CHC also boasts many non-contraceptive benefits, including:
Like all medicines, CHC can cause side-effects. However, many of the side-effects associated with CHC, such as skin changes, mood disturbances, headaches, genital irritation, tiredness, bloating, and menstrual pain, can be attributed to the hormone-free interval. The standard, licenced posology of administration of all CHC is use of the active for 21 days followed by a seven day hormone-free interval or break. Research studies have shown that there is no physiological need for a monthly bleed, as there is no evidence of histological abnormalities or endometrial thickening in the absence of a monthly bleed. The 28-day regimens for CHC were designed in the 1950s, and the inclusion of a seven-day hormone-free interval was driven by social and cultural factors, rather than having any basis in biology or drug safety/efficacy. This has resulted in the FSRH supporting tailored regimens for the use of CHC, which reduce the frequency of withdrawal bleeds, reduce the symptoms associated with the hormone-free interval and potentially increase the contraceptive efficacy of CHC. Tailored regimens can theoretically increase the contraceptive efficacy of CHC with ‘typical’ use, as most failures of CHC occur around the hormone-free interval — if the hormone-free interval is extended due to errors in CHC taking, ovulation can occur and an unintended pregnancy can result.
CHC administration regimens can be tailored in different ways. Standard use of CHC involves 21 days of active CHC, which can be 21 days of taking the oral contraceptive pill, insertion of one vaginal ring for 21 days or one transdermal patch applied weekly for three weeks, followed by a seven-day hormone-free interval. Tailored use of all CHC methods (oral pill, vaginal ring or transdermal patch) is supported by the FSRH but is unlicensed. CHC regimens can be tailored as follows:
The oestrogen and progestogen used in CHC can vary. The oestrogen choice in CHC is most often ethinylestradiol but the daily dose varies between different oral preparations. The dose of ethinylestradiol is between 20 and 40 micrograms per pill. The low strength (20 micrograms) is found in pills such as Microlite and Yasminelle, whereas the standard strength of between 30 and 35 micrograms per pill is found in pills such as Ovranette and Yasmin. Most CHC pills are monophasic and the dose of both oestrogen and progestogen are the same in every pill. Multiphasic preparations such as Logynon have varying dosages of oestrogen and progestogen throughout the cycle; Logynon has between 30 and 40 micrograms of ethinylestradiol at different points in the cycle. Progestogens also vary between different CHC options. There are many different types of progestogen in marketed CHCs, including second-generation progestogen levonorgestrel, third-generation progestogens desogestrel, etonogestrel and gestodene and newer progestogens drospirenone, dienogest and nomegestrol acetate. Third generation and newer progestogens give rise to less of the common side-effects, such as acne, headache, mood changes and breakthrough bleeding. However, third and newer generation progestogens come with one downside of increased risk of venous thromboembolism (VTE), a rare but serious side-effect from CHC.
Users of CHC have an increased risk of VTE (deep vein thrombosis and pulmonary embolism) as well as arterial thromboembolism (ATE) (myocardial infarction and ischaemic stroke). The risk of VTE in CHC users varies by progestogen used and by oestrogen dose. The highest risk is with third and newer generation progestogens and is estimated to give rise to between nine and 12 VTE cases per 10,000 women per year, when the baseline rate is two per 10,000 cases per year. VTE risk is also increased with increasing doses of oestrogen. Similarly, the increased risk of ATE seems to be associated with increasing oestrogen dose. Overall, if a combined oral contraceptive is being prescribed, the risk of VTE and ATE is lower with a pill containing less than 30 micrograms ethinylestradiol with second-generation progestogen, levonorgestrel (for example, Microlite or Leonore). Users of CHC are also at a slight increased risk of developing breast cancer and cervical cancer compared to never-users of CHC.
Guidelines have been developed called the UK Medical Eligibility Criteria (UKMEC guidelines) to mitigate against the development of the above serious medical conditions by users of CHC. It is known that certain risk factors increase the risk of VTE, including increasing age, smoking and a BMI over 30kg/m2. Similarly, risk factors for ATE include increasing age, smoking, hypertension and migraine with aura. For this reason, UKMEC guidelines assign a higher level of risk to prescribing CHC for patients with these characteristics.
The main counselling points for any patient receiving CHC are as per Table 1.
Table 1: Main counselling points
| Pharmacist advice | Further information | |
| 1. Indication | Primarily used as contraceptive. Active immediately if started from days one to five of a natural menstrual cycle. | CHC can also be started at any other time of the cycle, with the advice to use an additional contraceptive method for seven days as long as the prescriber can be reasonably certain that the patient is not pregnant. |
| 2. Posology of use | It should be explained how to adhere to the CHC regimen — traditional vs tailored. Take as prescribed, because the risk of some of the serious side-effects, such as clots, is higher in the first months of use or when restarting after a break of at least a month. | |
| 3. Missed pills | Explain concept of missed doses of CHC i.e., when a pill is taken >12 hours late, if the transdermal patch detaches for >24 hours, if the vaginal ring is expelled for >three hours, or if patient has severe vomiting or diarrhoea. | Emergency contraception may be required if one or more doses are missed; patient should be encouraged to speak to their pharmacist if this happens. |
| 4. Choice of emergency contraception for CHC users | If a patient has missed a dose of their CHC, emergency contraception (EC) may be indicated. The Cu-IUD is the most effective method of EC. Levonorgestrel is a progestogen, available in an oral formulation, and can be used by patients who are taking CHC. It can be used up to 72 hours after unprotected sexual intercourse (UPSI) and CHC can be restarted immediately. Refer to CHC SmPC for advice on contraindications, recommencement and information on additional contraceptive method requirements. | Ulipristal acetate is a progesterone receptor modulator and taking CHC in the seven days prior or the five days after ulipristal acetate may reduce the effectiveness of ulipristal acetate. Therefore, CHC should not be restarted for five days post ulipristal acetate and then requires a number of days until it is effective as a contraceptive again (for example, seven days for monophasic CHC pills and nine days for multiphasic CHC pill Qlaira). Refer to CHC SmPC for advice on contraindications, recommencement and information on additional contraceptive method requirements. |
| 5. Side-effects | Side-effects can occur, most frequently close to the hormone-free interval. Common side-effects are headache, breakthrough bleeding or mood changes. It is also worth noting that side-effects have been found to occur during the first few cycles, but generally do not persist with continued use. | If the patient finds any side-effect intolerable, they may be advised to speak to the prescriber about possible tailoring of the CHC regimen or a switch to a newer-generation progestogen, both of which have been shown to reduce side-effects. |
| 6. Serious adverse effects | Inform patients of small possibility of a serious side-effect such as VTE, ATE or cancer developing. For VTE/ATE, they should be counselled to seek immediate help if they experience calf pain, swelling and/or redness, chest pain, breathlessness and/or coughing up blood or any one-sided weakness in their body or face. Patients should also be asked to seek medical help if they notice any breast changes or unscheduled bleeding. | Patients can be reassured that these are incredibly rare adverse effects and can generally be managed if medical help is sought in a timely manner. |
| 7. Interactions | Patients should be informed that there can be drug-drug interactions which affect CHC. If any new medicine is started, they should inform the prescriber and dispensing pharmacist that they are taking CHC so that an interaction check can be carried out. | Enzyme inducing drugs can reduce the effectiveness of CHC and may mean that the CHC needs to be switched to an alternative form of contraception. The other main interaction to be aware of is with emergency contraception (see point six). |
In summary, CHC is likely to remain a popular contraceptive choice. It is important that we are familiar with the changes in the way people are using CHC, by following tailored regimens.
Insert into bubble: The second article in this series will review the progesterone only pill.
References available on request.
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