Contraception: The Complete Guide to All Available Methods

Sophie's expression — 27, software engineer, sitting across from me in my consulting room — oscillated between bewilderment and a tinge of exasperation. She'd just spent forty minutes on a forum where one poster claimed "the pill messes everything up", another swore the IUD "hurts like absolute hell", and a third explained that natural methods were "about as reliable as a chocolate teapot". Sophie had one question: "What's actually true?"

That is precisely the question this guide will answer. No judgement, no dogma — just the data. Because when it comes to contraception, the difference between information and opinion can have very concrete consequences for your life.

Theoretical vs real-world effectiveness: the distinction that changes everything

Let's start with the most important — and most misunderstood — concept in all of contraception. When you're told a method is "99% effective", that means in perfect use, out of 100 women using it for a year, only one will become pregnant. That's theoretical effectiveness.

Real-world effectiveness, however, accounts for actual life: missed pills, handling errors, drug interactions, vomiting after taking a dose. And that's where the numbers shift — sometimes dramatically.

The Pearl Index — named after biologist Raymond Pearl, who devised it in 1933 — measures the number of unintended pregnancies per 100 women using a method for one year. The lower the number, the more effective the method:

• Subdermal implant: 0.05% (theoretical) → 0.05% (real) — virtually no room for human error
• Hormonal IUD: 0.2% → 0.2%
• Copper IUD: 0.6% → 0.8%
• Combined pill: 0.3% → 9% — this is where the gap is staggering
• Male condom: 2% → 18%
• Natural methods (symptothermal): 0.4% → 24%
• Withdrawal: 4% → 22%

What these figures reveal is that there are two categories of contraception: those that depend on you (pill, condom, natural methods) and those that work independently of your daily vigilance (implant, IUD). Neither is inherently better — but it's a fundamental selection criterion that too many prescribers forget to mention.

Hormonal methods: pill, patch, ring, implant, injection

All hormonal contraceptives work on the same fundamental principle: altering the hormonal balance to prevent ovulation, thickening cervical mucus (making sperm passage virtually impossible), and thinning the endometrium. The molecules and delivery routes differ, but the logic remains identical.

The combined pill (oestrogen-progestogen)

It combines a synthetic oestrogen (ethinylestradiol or estradiol) with a progestogen. There are four "generations" — a term that's misleading because the latest isn't necessarily better than the first.

Second-generation pills (levonorgestrel) carry the lowest thromboembolism risk among combined pills. Third and fourth generations (desogestrel, gestodene, drospirenone) roughly double that risk. The MHRA and FSRH are clear: first-line prescribing should be a second-generation pill unless there's a specific clinical reason for another.

The combined pill's benefits extend beyond contraception: acne reduction (certain formulations), lighter and less painful periods, reduced long-term risk of endometrial and ovarian cancer. But it requires a daily dose at the same time — and that's where things fall apart for many women.

The progestogen-only pill (mini pill)

Oestrogen-free, it suits women with contraindications to oestrogen: migraine with aura, history of thromboembolism, smoking over 35, hypertension. Desogestrel 75 µg offers a 12-hour missed-pill window — far more forgiving than the traditional 3-hour window.

Its main drawback: irregular bleeding, especially in the first 3 to 6 months. Around 20% of women eventually stop having periods altogether, which is medically harmless but psychologically unsettling for some.

The contraceptive patch

A weekly patch (Evra® in the UK) releasing ethinylestradiol + norelgestromin. Three weeks on, one week off. Its advantage: you only think about it once a week. Its limitations: it sometimes peels off, can irritate skin, and effectiveness decreases in women over 90 kg.

The vaginal ring

A flexible ring (NuvaRing®) inserted into the vagina for three weeks, removed for one. Same hormonal principle as the combined pill, but local delivery. Most women don't feel it — and most partners don't either.

The subdermal implant

A 4 cm rod inserted under the skin of the upper arm (Nexplanon®), effective for 3 years. It's the most effective contraceptive that exists — across all methods. Its real-world failure rate is 0.05%, meaning 1 pregnancy per 2,000 women per year.

Possible side effects: irregular bleeding (the most common reason for removal), moderate weight gain in some women (average 1-2 kg, not the 10 kg you sometimes read about), acne. These effects typically diminish after 6 months.

The depot injection

Medroxyprogesterone acetate (Depo-Provera®), administered every 12-13 weeks by intramuscular injection. Effective but with a sometimes lengthy return to fertility — up to 12 months after stopping. NICE advises caution in under-18s due to potential impact on bone mineral density.

Intrauterine devices: copper and hormonal

Let's call it the IUD (intrauterine device) rather than "the coil" in clinical terms — though the colloquial name persists, it carries no stigma in British English. What matters is debunking the persistent myth that it's only suitable for women who've already had children.

NICE and the FSRH are unequivocal: the IUD can be offered to nulliparous women (who have never given birth). Any clinician refusing insertion on that basis alone is applying outdated guidance.

The copper IUD

No hormones whatsoever. Copper acts as a natural spermicide and triggers a local inflammatory reaction that prevents implantation. Duration: 5 to 10 years depending on the model. It's the only long-acting contraception that is entirely hormone-free.

Notable effects: periods are often heavier and more painful, especially in the first 3 to 6 months. For women who already had light periods, it's generally well tolerated. For those who already suffered heavy bleeds, it's probably not the ideal choice.

The hormonal IUD (levonorgestrel)

It releases a small dose of progestogen directly into the uterus. Two sizes exist: Mirena® (52 mg, 5 years) and Kyleena® (19.5 mg, 5 years, smaller, suited to nulliparous women). The major advantage: periods are significantly reduced, with 20-30% of users having no periods at all after one year.

Insertion: what nobody tells you

Pain during insertion is the most commonly cited barrier. Let's be honest: it exists, it varies enormously from person to person, and it's often underestimated by practitioners. Some women describe it as "a big cramp"; others as "the worst pain I've ever felt". This variability is real and should not be minimised.

Strategies to reduce discomfort: antispasmodic + NSAID one hour before, cervical priming (debated but offered by some gynaecologists), insertion during menstruation, and above all — a practitioner who takes the time to explain each step as it happens.

Barrier methods: condoms, diaphragm, cervical cap

The external (male) condom

The only contraceptive method that also protects against STIs — a dual benefit nothing else matches. Its theoretical effectiveness is 98%, but it drops to 82% in typical use. Failure causes: improper storage (heat, wallets), oil-based lubricants with latex, wrong size, incorrect application.

A detail rarely mentioned: there are over 50 condom sizes available on the market. A condom that's too tight is more likely to break; too loose, to slip off. Brands like MySize or TheyFit offer tailored sizing — an investment that directly increases effectiveness.

The internal (female) condom

Less well known, it can be inserted up to 8 hours before intercourse. Made of polyurethane or nitrile (alternative for latex allergies), it offers 95% theoretical effectiveness. Its main obstacle: cost (around £2 per unit vs £0.20 for an external condom) and a placement technique that takes some practice.

The diaphragm and cervical cap

Placed at the back of the vagina before intercourse, they cover the cervix and must be used with spermicide. Moderate effectiveness (88% in typical use for the diaphragm). They're seeing a slight resurgence among women seeking hormone-free, non-permanent contraception — but they require genuine learning to use properly.

Natural methods and fertility awareness

Important clarification: "natural method" doesn't mean "no pregnancy risk". The term is misleading and has contributed to unintended pregnancies. Let's call them Fertility Awareness-Based Methods (FABMs).

The symptothermal method

The most rigorous and effective FABM. It combines observation of three markers: basal body temperature (taken every morning upon waking), cervical mucus, and cervical position. In perfect use, the Sensiplan study (2007, 900 women, 17,000 cycles) showed 99.6% effectiveness — comparable to the pill.

But — and this is a significant but — this effectiveness requires serious training (3-6 months with a certified instructor), unwavering daily discipline, and a cooperative partner during fertile days (abstinence or barrier method). In typical use, effectiveness falls to between 76% and 88%.

Withdrawal (coitus interruptus)

Theoretical effectiveness: 96%. Real-world: 78%. The gap is explained by pre-ejaculate potentially containing sperm (studies are conflicting, but the precautionary principle applies) and the difficulty of perfect control every single time. It is not recommended as a primary contraceptive method.

The Standard Days Method

Treat days 8-19 of the cycle as fertile and abstain or use a barrier during that window. Simple but rigid — and only valid for women with very regular cycles (26-32 days). Real-world effectiveness: around 88%.

Permanent contraception: tubal ligation and vasectomy

We don't talk about these enough — yet they're increasingly chosen by people who've completed their families or who've decided not to have children.

Tubal ligation

Surgical procedure under general anaesthetic, usually via laparoscopy. In the UK, there's no legally mandated waiting period, but most NHS trusts require a counselling discussion and adequate reflection time. Effectiveness: 99.5%. The most commonly reported regret is among women who had the procedure before 30 — hence the importance of thorough counselling.

Vasectomy

Simpler, faster (20-30 minutes under local anaesthetic), fewer complications than tubal ligation. In the UK, around 15% of men opt for vasectomy — significantly higher than in many European countries. A semen analysis at 12 weeks post-procedure is required to confirm effectiveness.

Reversal (vasovasostomy) exists but is not guaranteed — so vasectomy should be considered permanent at the point of decision.

Emergency contraception

This isn't a regular contraceptive method — it's a safety net. And like any safety net, you'd rather not need it, but knowing it exists is vital.

Levonorgestrel (Levonelle®): effective up to 72 hours after unprotected intercourse, but its effectiveness decreases rapidly — 95% within the first 24 hours, 85% between 24 and 48 hours, 58% between 48 and 72 hours. Available over the counter in pharmacies across the UK, free from most sexual health clinics.

Ulipristal acetate (ellaOne®): effective up to 120 hours (5 days), with stable effectiveness throughout the entire window. Available from pharmacies without prescription in the UK since 2015. Its effectiveness may decrease in women over 85 kg — something the manufacturer was slow to acknowledge.

Emergency copper IUD: the most effective emergency method (99.9%), can be fitted up to 5 days after unprotected intercourse. It then stays in place as regular contraception. Underused because it requires a quick appointment, but increasingly offered by sexual health services and some GPs.

How to choose: the 7 criteria that actually matter

The best contraception doesn't exist in the abstract. The best contraception is the one you'll use correctly and that fits into your life without complicating it. Here are the criteria to weigh:

1. Your tolerance of hormones. If you have a history of thrombosis, migraine with aura, if you smoke over 35, or if you've had bad experiences with hormones — consider the copper IUD, barrier methods, or symptothermal method.

2. Your relationship with daily routines. Regularly forgetting your pill? LARC methods (Long-Acting Reversible Contraception — implant and IUD) were made for you. Fit and forget for 3 to 10 years.

3. Your pregnancy plans. Considering pregnancy in the next 6-12 months? The pill or condoms offer immediate return to fertility. The implant and IUD do too (simple removal), except the injection which can delay return by up to 12 months.

4. Your current periods. Very heavy periods? The hormonal IUD can reduce them by 90%. Light, regular periods? The copper IUD might make them heavier — worth anticipating.

5. STI protection. If you have multiple partners or a new partner, only condoms protect against STIs. Any other method should be combined with condoms in that context.

6. Your body. The patch loses effectiveness above 90 kg. Some pills are less well absorbed after bariatric surgery. Smaller-frame IUDs exist for smaller uteri.

7. Long-term cost. The copper IUD, over 10 years, works out to roughly £2 per month. The implant around £3 per month. The pill approximately £5-8 per month on private prescription (free on NHS). Condoms £5-15 per month depending on frequency. The NHS provides most methods free of charge — which fundamentally changes the cost equation compared to many other countries.

The 10 most persistent contraception myths

Ten claims I hear in consultations with depressing regularity:

Myth 1: "The IUD is only for women who've had children."
False. NICE and the FSRH recommend the IUD as a first-line contraceptive option for all women, including those who've never given birth. Any clinician who refuses insertion on that basis alone is applying outdated guidance.

Myth 2: "The pill makes you gain weight."
Large-scale studies show no significant weight gain with modern pills. A Cochrane meta-analysis of 49 trials found no causal link. However, the water retention of the first few months (1-2 kg) is real but transient.

Myth 3: "You should take breaks from the pill."
No scientific basis whatsoever. Breaks have no health benefit and expose you to unintended pregnancies. This myth dates from an era when hormonal doses were much higher.

Myth 4: "The IUD increases infection risk."
Infection risk is slightly elevated in the 20 days following insertion, then returns to baseline. STI screening before fitting eliminates this residual risk. The IUD does not promote infections long-term.

Myth 5: "Hormones are bad for your health."
That's like saying "medication is bad for your health". Hormonal contraceptives have documented risks and documented benefits. The risk-benefit calculation is individual, not ideological.

Myth 6: "The pill causes infertility."
Fertility returns fully within 1-3 cycles after stopping the pill for the vast majority of women. Any slight delay observed is related to cycle normalisation after years of ovulation suppression, not pill-induced damage.

Myth 7: "You can't get pregnant during your period."
You can. Sperm can survive up to 5 days in the reproductive tract. An early ovulation (day 10-11 of a short cycle) can be reached by sperm deposited on day 6.

Myth 8: "The morning-after pill is an abortion."
No. It delays or prevents ovulation. If ovulation has already occurred and an embryo has implanted, it does not terminate the pregnancy. Biologically, it's a contraceptive, not an abortifacient.

Myth 9: "Condoms are always enough."
For STI protection, yes. As sole contraception, their 82% real-world effectiveness makes them less reliable than other options. Dual protection (condoms + another method) is recommended when both STI prevention and pregnancy prevention are needed.

Myth 10: "Natural methods are for anti-science women."
Rigorous symptothermal practice is based on solid physiological data. The Sensiplan study shows effectiveness comparable to the pill in perfect use. The issue isn't the science — it's the gap between perfect and typical use, which is substantial.