27th June 2023

Contraception

UK Contraceptive Options

The prescribing of contraceptives requires a consideration of multiple factors, including the person’s preferences, family aspirations, and lifestyle. Without contraception, 85% of premenopausal women would conceive within one year of regular unprotected intercourse.

Before a contraceptive method is chosen, the efficacy of each choice, as well as common adverse effects, should be discussed. Some contraceptives have interactions with other medications; for example, the enzyme-inducing agent rifampicin lessens the effectiveness of the combined oral contraceptive pill (COCP).

The Faculty of Sexual and Reproductive Healthcare has provided guidance in the form of the ‘UKMEC Summary of Hormonal and Intrauterine Contraception’ – this provides an easy cross-reference tool for clinicians to assess the suitability of a contraceptive based on a patient’s characteristics and comorbidities. The guidance rating is given as a number ranging from 1-4, with a 1 being no contraindications, a 2 being benefits outweigh risks, 3 suggesting risks may outweigh benefits, and 4 meaning that the use of the contraceptive poses an unacceptable health risk.

Barrier Methods

Male and female condoms provide a physical barrier to ejaculate, pre-ejaculate and cervicovaginal secretions entering the uterus. Fertilisation is prevented and the risk of transmission of sexually transmitted infections (STIs) is greatly reduced. No fitting is required (unlike other barrier methods) but care should be taken to ensure the patient is aware of the risks of failure. In practice, this is 18% for male condoms, meaning 18 in 100 women relying solely on this method of contraception will conceive within the first year, and 21% for female condoms.

Diaphragms and cervical caps both prevent sperm from reaching the cervix but do not prevent direct contact between the penis and vagina and so do not offer the same protection against STIs. Both diaphragms and caps need fitting, including resizing after childbirth due to the change in the cervix, and should be used in conjunction with spermicide (a chemical barrier to sperm entering the cervix). Failure rates for both when used in practice are at least 12%.

Combined Hormonal Contraceptives (CHCs)

CHCs contain oestrogen and progesterone, which works on the hypothalamo-pituitary axis to reduce the production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), thereby inhibiting ovulation. Additionally, CHCs affect the cervical mucus and endometrium to give a hostile environment for implantation.

Three CHC methods are available: a once-daily pill, a 7-day transdermal patch, and a 21-day vaginal ring. All the methods can be used ‘off label’ without a contraception-free interval, which prevents the withdrawal bleed. The efficacy of all three methods is similar, with in-practice use showing a 9% failure rate. Before starting a CHC, the UKMEC guidance should be carefully consulted with regards to smoking, age, obesity, and migraines with aura.

Progesterone-only methods

Methods include the once-daily pill (POP), the injection (which is given either 8- or 13-weekly depending on type) and the long-acting implant, which can be changed every three years. All methods work similarly to prevent conception in multiple ways, including increasing the thickness of cervical mucus and making the endometrium hostile to implantation. Additionally, ovulation is suppressed by preventing the midcycle peaks of LH and FSH.

All methods can be used while breastfeeding (injectable is UKMEC 2), can be used in patients with a previous venous thrombosis (UKMEC 2) and are safe in patients with a BMI >35. There is evidence to suggest that the POP reduces dysmenorrhea and mid-cycle ovulation pain.

All methods are associated with unscheduled menstrual bleeding, and the injectable can have up to a 1-year delay in fertility returning to normal once stopped. The injectable is also associated with weight gain and loss of bone mineral density, although this is usually recovered after discontinuation.

Intrauterine Contraception

There are two types of these long-acting contraceptives currently available in the UK: the copper intrauterine device (IUD) and the levonorgestrel intrauterine system (IUS). Both are inserted via the cervix and sit in the uterus with threads into the vagina (which allow the presence of the contraception to be checked after each menstrual cycle).

The copper IUD prevents fertilisation due to copper’s toxicity to ova and sperm. The IUS uses progestogenic effects within the endometrium to prevent implantation of the fertilised ova and thickens cervical mucus preventing sperm from entering the uterus; both methods are 99.2% effective. The IUS needs to be replaced every 3-5 years and can be used as a treatment for menorrhagia; disadvantages include the risk of expulsion and perforation of the uterus wall on insertion. The copper IUD is replaced every 5-10 years and is hormone-free, so it is safe for women with a history of blood clots and breast cancer. It can be associated with heavier menstrual bleeding, but this is not a contraindication.

Natural Family Planning

Natural contraceptive methods are less reliable than other methods but are widely acceptable and can be effective when taught to couples by trained providers. Fertility indicators are monitored during a woman’s cycle to prompt a change in sexual behaviours to prevent pregnancy. Fertility awareness methods (FAM) rely on monitoring signs such as basal body temperature, consistency of cervical secretions and changes in the cervix. It requires a woman to have a regular menstrual cycle to allow accurate prediction of ovulation. The lactational amenorrhea method (LAM) relies on a woman being less than six months postpartum, breastfeeding at least 85% of baby’s intake and complete amenorrhea; lactation stops ovulation by delaying gonadotrophin release.

Emergency Contraception

These methods are used when a person has had unprotected sexual intercourse (UPSI), including failure of contraceptive, for example ‘missed pill’, and does not wish to conceive. They should be considered if UPSI has occurred on any day of a natural menstrual cycle, if a hormonal method has been used incorrectly, from 21 days postpartum unless lactational amenorrhea criteria have been met, or 5 days from a miscarriage, abortion, or ectopic pregnancy.

Options include oral levonorgestrel, oral ulipristal acetate and the copper IUD. Both oral methods work by delaying or preventing ovulation, so are less effective if taken late in the cycle after ovulation has occurred. The copper IUD relies on its toxic effects on ova and sperm, so it is effective at any point in the cycle. Emergency contraception should be given as close to the UPSI as possible, with the more effective method being the copper IUD – this can be placed up to 5 days from UPSI. Ulipristal acetate is licensed for 5 days following UPSI, and levonorgestrel for 72 hours.

Sterilisation

Sterilisation for women is tubal occlusion and for men a vasectomy. Both are considered permanent methods of contraception, and the NHS does not routinely offer reversal. Both methods require a small surgical procedure. Female sterilisation is carried out laparoscopically and requires a general anaesthesia, which has associated risks.

Vasectomy has a failure rate of 0.05%, but a post-procedure sperm analysis (usually at 12 weeks) is required to confirm azoospermia, and additional contraceptives should be used until this time. Tubal occlusion has a failure rate of 0.5%. Tubal occlusion is associated with a slight protective effect against developing ovarian cancer; by contrast, vasectomy is associated with a slight increased risk of prostate cancer, although the relationship is not thought to be causal.