What to avoid when taking the contraceptive pill and the five common things that can make it less effective

• The contraceptive pill is a popular method of contraception.
• Currently, 17% of women in the UK rely on the pill as their primary form of contraception.
• However, there are certain everyday items that can reduce their effectiveness.

The contraceptive pill is still one of the most popular methods of contraception, with currently 17% of women in the UK relying on it as their primary form of protection.

It offers a 99% effectiveness rate when used correctly, however despite this high rate of protection, there are certain everyday items that may compromise this, with users often unaware of potential risks.

Duncan Reid, Senior Pharmacist and Head of Patient Safety at Pharmacy2U, explained: “The contraceptive pill continues to be a popular choice due to its convenience and reversibility. It also offers additional benefits, such as regulating menstrual cycles and, in some cases, improving acne.

“However, its effectiveness isn’t guaranteed if certain conditions are overlooked. By recognising potential risks and staying informed, users can take proactive steps to ensure consistent protection.”

Here are five reasons your contraceptive pill might not be working:

Grapefruit

This seemingly harmless fruit can have a big impact on many medications, including the contraceptive pill. It can have a surprising effect on how your body processes contraceptive hormones.

Grapefruit interferes with liver enzymes responsible for breaking down these hormones, which can lead to lower levels of active hormones in your bloodstream. To maintain the pill’s effectiveness, avoid grapefruit and grapefruit juice while taking it.

Taking certain other medications

Most medicines that can reduce the effectiveness of the contraceptive pill are known as “enzyme-inducers.” These medicines speed up the processing of hormones in the liver, which can lower the amount of contraceptive hormones absorbed into the bloodstream, making the pill less effective.

Enzyme-inducers include certain anti-epileptic drugs, medications for migraine and HIV, modafinil, and the herbal remedy St John’s Wort, often used for mental health conditions.

While it was once believed that antibiotics affected the pill’s reliability, this is now known to be untrue for most commonly prescribed antibiotics. Only two powerful antibiotics; rifabutin and rifampicin, typically used to treat tuberculosis or meningitis, are proven to interfere with the pill. To ensure your contraception stays effective, always inform your healthcare provider if you’re on the pill when starting any new medication or supplement.

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The stage of your cycle

When you start the pill, it’s important that you time it right with your menstrual cycle. For most pills, if you begin taking them on or before the fifth day of your period, you’ll be protected straight away. However, certain pills, like those containing drospirenone, require you to start on the first day of your cycle for immediate protection.

If you have a shorter cycle, typically 23 days or less, starting the pill as late as day five may not offer instant protection due to the possibility of early ovulation. In cases where the pill is started at any other time in your cycle, additional contraception; such as condoms, should be used for the first few days.

Vomiting

Vomiting soon after taking your pill, whether due to illness or another reason, can stop your body from properly absorbing the hormones. If you are sick within two hours of taking your pill, take another pill immediately and then continue with your next pill at the usual time.

If vomiting persists, use an additional form of contraception, such as condoms, until you’ve taken the pill consistently for seven days without vomiting. It’s essential to follow the missed pill guidance provided in your pill’s leaflet to maintain protection.

Extreme Temperatures

Contraceptive pills can lose their effectiveness if exposed to very high or low temperatures. Birth control should be stored in a cool, dry place at room temperature, between 20–25°C and should be protected from direct sunlight and kept away from places like cars, checked airplane luggage, and bathroom or kitchen cabinets.

If you’re travelling to a destination with a particularly hot or cold climate, consider discussing alternative contraceptive methods with your doctor or pharmacist to ensure consistent protection.

If you’re unsure about their effectiveness of your contraceptive pill, speak to your pharmacist or doctor for advice. In the meantime, use an additional form of contraception, such as condoms, to ensure protection.

You can find out more about the different methods of contraception and what choices are available to you on NHS.UK.