How effective the pill really is
Taken perfectly — same time every day, never missed — the combined pill is over 99 per cent effective. But with typical, real-life use, effectiveness is closer to 91 per cent, because people occasionally miss pills, take them late, or have interruptions. So yes, pregnancy on the pill is possible, though uncommon.
The gap between 'perfect use' and 'typical use' is entirely about consistency, which is good news — it means the things that reduce your risk are within your control.
What reduces the pill's effectiveness
The main culprits are missed or late pills, vomiting or severe diarrhoea within a couple of hours of taking it (so it isn't absorbed), and certain medications and supplements — including some antibiotics, epilepsy medications, and St John's Wort — that interfere with it.
Do you still ovulate on the pill? Taken correctly, the combined pill usually stops ovulation, which is a key part of how it prevents pregnancy. But if pills are missed, ovulation can slip through.
How to stay protected
Take your pill at the same time each day, use reminders, and know what to do if you miss one (the instructions differ depending on which pill and where in the pack). If you're on a medication that interacts, use backup contraception and check with a pharmacist or GP.
If you've missed pills and had unprotected sex, emergency contraception is an option. And if you keep finding the daily pill hard to remember, a longer-acting method like an IUD or implant removes the human-error factor. A GP can help you choose what fits your life.
Related condition
Contraception & the pill →References & sources
This content is general information and not a substitute for individual medical advice. Please consult a GP for your personal situation.
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