Contraceptive Methods Compared

See also:

• Emergency contraception,
• Contraception and special groups,
• Contraception and the mature woman,
• Contraception and young people,
• Depot and implant hormonal contraception,
• Ethnocultural issues in contraception.

72% of women aged 16–49 years use some type of contraception:

• 24% use the Combined oral Contraceptive Pill (CoCP)
• Woman or partner has been sterilised in 23% of cases
• 18% of women rely on male condom use
• Approximately one-third women under 18 years of age use contraceptives, half using condoms and half taking CoCP
• In women aged 18–29 years, twice as many women use CoCP as condoms (most frequent methods)
• Sterilisation is used more frequently in women aged over 30 years.

Two types of contraceptive failure:

• User failure – when contraceptive method isn't used properly
• Method failure – pregnancy results even though the contraceptive method was used properly. User failure rates are much higher than method failure rates, especially in first year of use.

Failure rates of methods in common use (annual percentage failure for 'real-world' users unless otherwise specified):

• CoCP ~0.1 pregnancies per 100 woman-years when used consistently and correctly¹ ('real world' annual failure rate 1–2%)
• Progestogen-only-pills ~0.5 per pregnancies per 100 woman-years when used consistently and correctly¹ ('real-world' annual failure rate 3–5%)
• Implants, IUCDs and levonorgestrel-releasing intra-uterine system <1%
• Male condoms 14%
• Diaphragm with spermicide 20%
• Cap with spermicide 20–40%
• 'Natural' methods 35%
• Withdrawal method 19%.

Combined Oral Contraceptive Pill (CoCP)

All contain a synthetic oestrogen and a progestogen.
Mode of action is prevention of ovulation, thickening of cervical mucus and reduction of endometrial receptivity. Also, recently introduced transdermal combined contraceptive, which appears on basis of current surveillance to be equivalent to CoCP.² Special advice needed if patch off for >24 hours.
Benefits:

• Highly effective, easy to reverse and convenient to use
• Can bring relief of menstrual problems
• May protect against PID²
• Reduces incidence of benign breast disease, ovarian cysts, ovarian cancer and endometrial cancer.³

• Breakthrough bleeding
• Weight gain – an epidemiologically questionable association^4,5
• Breast tenderness
• Acne
• Mood swings
• Increased risk of venous thromboembolism ~3–6 X that of non-users but much less than pregnancy with actual risk of event very low^6,7,8
• Increased risk of MI – most pronounced in women with risk factors such as smoking, hypertension and diabetes⁷
• Increased risk of stroke ~ 2 X that of non-users overall but higher in women who smoke and with hypertension⁷
• Slightly increased risk of breast cancer – 1.24 X that of non-users but as incidence of breast cancer under age 40 years is low, absolute risk in young women is small⁹
• Increased risk of cervical cancer – 1.31 X non-users but many cases are related to other factors, i.e. number of sexual partners, non-barrier contracepetive use causing HSV exposure⁹
• Increased risk of primary liver cancer – only with high dose oestrogen and absolute risk is very small indeed
• Increased overall mortality – despite careful selection and follow-up, increased mortality at age 20-24 years is 2/million users, 30-34 years 2–5/million users, 40-44 years 20–25/million users

Progestogen only pill

Contain one of the following: norethisterone, ethynodiol diacetate (metabolised to norethisterone) or levonorgestrel.
Mode of action – thickens cervical mucus, reduces receptivity of uterus and inhibits ovulation in some cycles.
Benefits:

• Reliable if taken correctly, easily reversible and convenient to use
• Avoids cardiovascular risks of oestrogen
• Can often be used by women with contraindications to CoCP
• Can be used during breast feeding.

• Menstrual problems such as amenorrhoea and breakthrough bleeding
• Needs to taken at the same time daily
• Increase risk of functional ovarian cysts (~30% increased risk) and possibility of increased risk of breast cancer (similar to CoCP).

Typically used for women who do not tolerate a CoCP or for whom they are contraindicated.

Injectable contraceptives

Products available in the UK:

• IM medroxyprogesterone acetate (Depo-Provera) – provides contraception for 12 weeks for women who have been advised of the chances of menstrual disturbance and the possibility of a delay in return to full fertility.
• IM norethisterone oenanthate (Noristerat) – licensed for short-term use with 2 injections only for women who need highly reliable contraception without chance of user error.

Mode of action – contain long acting progestogen that prevents ovulation, thickens cervical mucus and reduces uterine receptivity.
Benefits:

• Very effective and convenient
• Can be used during breast feeding.

• Cannot be quickly reversed
• Menstrual irregularities are common
• Weight gain – occurs in majority of women using Depo-Provera
• Delayed return of fertility – can be >1 year with Depo-Provera
• Possible risk of depression – not clearly shown yet
• Possible increased risk of breast cancer – not clearly shown yet.

Subdermal implant

Also known as progestogen-only subdermal implants (POSDIs).
Only one type available – etonogestrel implant (Implanon). Progestogen based, single, matchstick-sized rod that needs to be inserted following special training. Effective for 3 years but can be reversed by removal.
Benefits:

• Highly effective with very few pregnancies reported
• Long duration of action
• Reversible
• Very convenient.

• Irregular bleeding – common in first year but declines thereafter
• Weight gain is a common reason for discontinuation of this method of contraception along with headache and acne¹⁰

Copper IUCD

Currently seven copper IUCDs available, varying in size, shape and surface area of copper wire, and whether they are framed or frameless.¹¹ All require a different insertion technique and should only be fitted by adequately trained personnel. They can be left in place for 5 years, or until the menopause if inserted after the age of 40. All have a monofilament thread to permit check that device is in-situ and facilitate removal.
Mode of action – predominantly works by inducing an inflammatory response in the uterus which affects the viability of sperm and ova. Do not significantly interfere with implantation and should not be viewed as relying on abortion.
Benefits:

• Highly effective, reversible and convenient
• Effective immediately after fitting.

• Spotting and bleeding between periods
• Increased blood loss and more painful periods especially during first few cycles
• Displacement or expulsion – 1–7/1,000 insertions become expelled, usually during first 3 months and this may go unnoticed by the user
• Increased risk of PID – in first 20 days only and young at-risk women should be screened for chlamydia before insertion
• Uterine perforation – 1/1,000 insertions; appears to be unrelated to form of IUD or experience of person fitting it
• Ectopic pregnancy – only in event of an IUD failure so absolute risk is very low.

Levonorgestrel-releasing intrauterine system

See intra-uterine progestogen-only system.
Only one system available (Mirena) a T-shaped device relatively recently licensed for use.
Mode of action – reduces endometrial growth and prevents implantation, thickens cervical mucus, alters movement of sperm and can suppress ovulation in a proportion of cycles, actual intrauterine presence.
Benefits:

• Very effective, convenient and reversible¹²
• Reduces blood loss and dysmenorrhoea
• May reduce risk of PID compared with normal IUDs
• Does not significantly interact with other drugs as action is principally local.

• Menstrual irregularities are common in first few months
• Typical progestogenic side effects
• Dysfunctional ovarian cyst, but usually resolves spontaneously
• Need for fitting – larger than normal IUDs and may require cervical dilatation with local anaesthesia.

Diaphragms, caps and the vaginal sponge

Diaphragms are latex, dome-shaped devices with a flexible but stiff circular ring at their edge. Come in range of sizes from 55–100mm.
Three different types:

• Flat spring – for women with normal vaginal muscular strength
• Arcing spring – for women with poor vaginal muscular strength
• Coil spring –may cause less discomfort in some women.

Caps are smaller than diaphragms and fit closely over the cervix.
Both should be used with spermicidal creams.
Mode of action – barrier method and spermicidal effect.
Benefits:

• Insertion several hours prior to intercourse can allow more spontaneity than condoms
• May offer some protection against cervical carcinoma, STD and PID.

• Woman needs to be well motivated and careful in its use
• Spermicides can cause local irritant or allergic reaction
• Incidence of UTI increased with diaphragms.

The vaginal sponge is made of polyurethane impregnated with spermicide. It is soft, round and purported to be more comfortable and easier to use than diaphragms or the cap. However it has a higher failure rate than the diaphragm and higher discontinuation rates at 12 months, calling into question its supposed advantages.¹³

Femidom

Made of soft pliable polyurethane, pre-lubricated and with 2 flexible rings.
Mode of action – barrier method.
Benefits:

• No known side effects, helps prevent STD and possibly reduces risk of cervical carcinoma
• Can be inserted prior to intercourse.

• Needs careful insertion
• Can be pushed into vagina or bypassed during penetration
• May be uncomfortable for either partner.

Male condoms

Mode of action – barrier method
Benefits:

• Readily available in chemists and non-healthcare settings.
• Protects against STD and may protect women against cervical cancer.

• Relatively expensive if purchased (free condom uptake at FPCs is low)
• Needs prior planning
• Lacks spontaneity
• Requires cooperation of both partners
• May reduce sensitivity
• Can tear or slip off during intercourse.

Natural family planning

Several methods available including calendar, temperature, cervical mucus testing and cervical palpation. Also Persona™ device that measures urinary estrone 3-glucuronide and LH.
Benefits:

• No side effects
• Complies with religious beliefs and practices of some patients.

• Requires considerable commitment from both partners
• Unreliable for women with unpredictable menstrual cycles.

Special groups

Several groups of women have special requirements regarding contraception (see related article on contraception and special groups). They include:

• Older women >40 years old
• Women who are breast feeding
• Women who have migraine headaches
• Smokers
• Younger women
• Diabetic women.