Contraception: Comparing the Options Honestly
Choosing contraception is usually presented as a list of options with effectiveness percentages. The numbers that matter are the typical-use figures, not the perfect-use ones, and the right choice depends as much on how a method fits your life as on how it works.
Perfect use versus typical use
Every method has two numbers: how it performs when used exactly correctly every time, and how it performs in real life. The gap is large for methods that depend on the user and almost zero for those that do not.
Approximate pregnancies per 100 women in the first year:
| Method | Perfect use | Typical use | |—|—|—| | Implant | 0.05 | 0.05 | | Hormonal IUD | 0.2 | 0.2 | | Copper IUD | 0.6 | 0.8 | | Vasectomy | 0.1 | 0.15 | | Female sterilisation | 0.5 | 0.5 | | Injection | 0.2 | 4 | | Combined pill | 0.3 | 7 | | Progestogen-only pill | 0.3 | 7 | | Male condom | 2 | 13 | | Withdrawal | 4 | 20 | | Fertility awareness | 0.4–5 | 2–23 | | No method | — | 85 |
The top group are called LARCs, long-acting reversible contraceptives, and their advantage is simply that there is nothing to forget.
The main methods
Combined pill (oestrogen + progestogen). Also reduces period pain and heavy bleeding, improves acne and lowers ovarian and endometrial cancer risk. Not suitable with migraine with aura, high blood pressure, smoking over 35, previous clot, certain liver disease, or breastfeeding in the early weeks. Small increased risk of blood clots.
Progestogen-only pill. Suitable where oestrogen is not, including breastfeeding. Older types need strict timing; desogestrel-containing versions allow a 12-hour window. Irregular bleeding is common.
Implant. A small rod under the skin of the upper arm, lasting about three years. The most effective reversible method. Unpredictable bleeding is the main reason for removal, and it should be discussed before insertion rather than after.
Hormonal IUD. Lasts five to eight years depending on the device. Makes periods much lighter and often stops them, which is a treatment in its own right for heavy menstrual bleeding and a cause of iron deficiency.
Copper IUD. Hormone-free, lasts up to ten years, and is the most effective form of emergency contraception when fitted within five days. Often makes periods heavier and more painful, particularly in the first months.
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Injection. Every 8 to 13 weeks. Convenient but associated with delayed return of fertility of up to a year, weight gain in some users, and reduced bone density with prolonged use.
Condoms. The only method that also protects against sexually transmitted infections, which is a decisive point in many situations and a reason to use them alongside another method.
Sterilisation. Permanent. Vasectomy is simpler, safer and more effective than female sterilisation, done under local anaesthesia, with no effect on testosterone, erections or ejaculation volume. It requires a semen check after about three months before relying on it, and another method until then.
Fertility awareness methods can work but demand consistent daily tracking of temperature, cervical mucus and cycle, regular cycles, and agreement from both partners. Apps vary enormously in rigour.
Withdrawal is better than nothing and far worse than anything else on this list.
Emergency contraception
- Copper IUD: most effective, up to 5 days, and continues as ongoing contraception
- Ulipristal acetate: up to 5 days, more effective than levonorgestrel
- Levonorgestrel: up to 3 days, less effective with higher body weight
None of these causes abortion; they work by delaying or preventing ovulation. They do not work if implantation has already occurred, and they are far less effective than regular contraception.
Myths worth correcting
- Contraceptive pills do not cause permanent infertility. Fertility returns quickly after stopping, with the injection the one exception for a delay
- The IUD is suitable for women who have never had children
- “Pill breaks” are unnecessary and expose you to pregnancy risk
- Emergency pills are not meant for repeated use, but using one does not harm future fertility
- Antibiotics other than rifampicin and rifabutin do not reduce pill effectiveness
- Breastfeeding is not reliable contraception unless very strict conditions are met
Things that genuinely reduce effectiveness
Vomiting or severe diarrhoea within a few hours of a pill, enzyme-inducing drugs including rifampicin, some antiepileptics and St John’s wort, missed pills, and late injections.
Choosing
Consider: how important is it to avoid pregnancy now; can you take something daily; do you want lighter or absent periods; are you also at risk of sexually transmitted infections; do you want children in the next year or two; and what medical conditions do you have. Then discuss with a doctor, since several methods are unsuitable with specific conditions.
This is general information. Contraceptive choice depends on your medical history, blood pressure, migraine type and other medications, so it should be decided with a doctor.