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Progestin-only pill: A daily contraceptive

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 19.10.2023 | 5 minutes read

The progestin-only pill (POP) is a type of contraception. It contains a progesterone hormone. The hormone closely resembles the progesterone hormone produced by a woman’s ovaries.

POPs contain norethindrone (Errin, Nora-BE, Ortho Micronor). The POP is also referred to as the mini pill.

How effective is the progestin-only pill?

When taken consistently and correctly, the progestin-only pill can be highly effective in preventing pregnancy, with a typical failure rate of around 1 in 10 per year. However, its efficacy may be slightly lower compared to combined oral contraceptives (COCs), particularly in users who have difficulty adhering to the strict daily dosing schedule required for optimal effectiveness.


The progestin-only pill offers several potential benefits for individuals seeking contraception. Since it contains only progestin hormones, it may be suitable for individuals who cannot tolerate estrogen-containing contraceptives due to medical contraindications or side effects. Additionally, the POP may be a preferred option for breastfeeding individuals, as it does not interfere with milk production or quality and can be initiated immediately postpartum.

Who is the progestin-only pill for?

Most women of childbearing age can take the POP. It is commonly prescribed to women who cannot take the combined oral contraceptive pill because it contains an estrogen hormone.

Should anyone not take the POP?

As always, do not take the medication if you are allergic to any ingredients. Your doctor or contraceptive nurse will decide whether it is appropriate for you to take the POP. You should not take the POP if you have breast cancer or are already pregnant. It may not be suitable for you to take the POP if you have liver problems, a history of breast cancer, or a rare genetic condition (known as acute porphyria). Also, the POP may not be the right contraception option for you if you take certain medications. This includes some epilepsy and HIV medications and antibiotics called rifampicin and rifabutin.

How does it work?

The primary mode of action of the POP is to stop the ovaries from releasing an egg (ovulation). It will not work if you are already pregnant. It increases the thickness of the mucus produced by the cervix (neck of the womb). The thickened mucus acts as a barrier to prevent sperm from reaching and fertilizing an egg. If taken correctly, the POP is more than 99% effective at preventing pregnancy. The POP does not protect against sexually transmitted infections. Therefore, it is best to use condoms as well.

Are there any side effects?

As with all medications, some people may experience side effects. Potential side effects from the POP can include feeling sick, being sick, breast tenderness, headache, acne, an increased or decreased sex drive (libido), and mood swings. You should speak with your doctor or pharmacist if any side effects become bothersome.

Despite what many people believe, there is no conclusive evidence suggesting that the POP causes weight gain. Unlike the combined oral contraceptive pill, the evidence does not show that the POP increases your risk of developing a blood clot.

The POP can affect your periods. Some women will continue to have regular periods. However, other women may have less or more frequent periods or no periods at all. Some women may experience lighter or prolonged bleeding or bleeding between periods (known as spotting). These changes in your periods are more common during the first few months of treatment and are usually no cause for concern. If they are persistent (last longer than three months), you should speak with your doctor.

The POP may slightly increase your risk of developing breast cancer. However, this has not been fully established. If there is an increased risk, it is small and will reduce with time after you stop taking the POP. Nevertheless, you should promptly speak with your doctor if you notice any changes in your breasts, such as any lumps, changes in the nipple, or dimpling of the skin.


What are the main differences between the progestin-only pill and combined oral contraceptive (COC) pills ?

The main difference between the progestin-only pill and COCs is the absence of estrogen in the former. While COCs contain both estrogen and progestin, the POP contains only progestin hormones. Additionally, the POP must be taken at the same time every day to maintain its effectiveness, whereas COCs have a 12-hour window for pill-taking.

Who is a good candidate for the progestin-only pill?

The progestin-only pill may be suitable for individuals who cannot tolerate estrogen-containing contraceptives due to medical contraindications or side effects. It may also be preferred by breastfeeding individuals, as it does not interfere with milk production or quality and can be initiated immediately postpartum.

Is the progestin-only pill suitable for everyone?

While the progestin-only pill is generally well-tolerated by most individuals, certain factors, such as a history of thromboembolic disorders, liver disease, or uncontrolled hypertension, may influence its suitability. It is essential to discuss individual medical history and any pre-existing health conditions with a healthcare provider before starting the POP.

What should I do if I miss a pill or experience breakthrough bleeding?

If you miss a pill or experience breakthrough bleeding while taking the progestin-only pill, follow the guidance provided by the pill manufacturer or healthcare provider. This may involve taking the missed pill as soon as possible, using backup contraception, and seeking medical advice if breakthrough bleeding persists or worsens.

Can I use the progestin-only pill as emergency contraception?

While the progestin-only pill is not to be used as emergency contraception, certain formulations of the POP may be used off-label for this purpose. It is essential to consult your pharmacist or doctor for guidance on using the POP or other forms of emergency contraception effectively and safely.

How long does it take for fertility to return after stopping the progestin-only pill?

Fertility typically returns shortly after discontinuing the progestin-only pill, although the exact timing may vary among individuals. Some users may ovulate and conceive soon after stopping the POP, while others may experience a delay in fertility return. It is advisable to use alternative forms of contraception if pregnancy is not desired immediately after discontinuing the POP.

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This article has been written by UK-based doctors and pharmacists, so some advice may not apply to US users and some suggested treatments may not be available. For more information, please see our T&Cs.
Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 19.10.2023
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