Mini Pill: Causes of Side Effects, Their Treatment and Pregnancy Prevention

The mini pill is a contraceptive pill that contains only one hormone, a progestogen, and no oestrogen. It suits many people who cannot take the combined pill, including those who are breastfeeding or get migraine with aura. This guide explains how the mini pill or progesterone only pill works, the types sold in Australia, what to do after a late dose, and the side effects to expect.

Key takeaways

• It contains no oestrogen, so it suits many people who cannot take the combined pill.
• Take it every day with no break; some types allow only 3 hours' leeway for a late dose.
• Irregular bleeding is the most common side effect and often settles within a few months.
• A Medio doctor can review whether it suits you by phone and send an eScript where suitable.

What the Progestogen Only Pill Is

The mini pill is a daily tablet containing a progestogen, a man made version of the hormone progesterone, and you take a tablet every day without a break between packs. Depending on the type, it thickens cervical mucus, stops the ovaries releasing an egg, or both.

All three are only available on prescription in Australia. Nausea, headaches and breast tenderness can occur in the first months and usually ease.

Who Progestogen Only Contraception Suits

Progestogen only contraception suits people who want or need to avoid oestrogen. That includes those who are breastfeeding, smoke and are over 35, get migraine with aura, have had a blood clot or have high blood pressure, for whom combined contraception carries more risk.

It can be started soon after giving birth and used at any age until menopause. Overseas the same method is often called a progestin only mini pill, and some people simply prefer a contraceptive with fewer hormones. It is not the best fit for anyone who struggles to take a tablet at the same time each day, has unexplained bleeding from the uterus or has had breast cancer; an implant or an IUD may work better for them. The ovaries return to their usual cycle soon after you stop, so fertility comes back quickly, and your doctor checks which contraception suits you.

How Progestogen Thickens Mucus and Stops Ovulation

Progestogen works in two ways. It thickens the mucus at the entrance to the womb so sperm cannot swim through, and in higher doses it stops ovulation, the monthly release of an egg. The traditional types rely mostly on the thicker mucus, and that effect wears off about a day after each tablet, which is why a late dose can let sperm through and why condoms are needed for a short time afterwards. The drospirenone type keeps the ovaries from releasing one in most cycles, so it allows more leeway. Because each mini contraceptive pill holds only progestogen, at a steady low level, it avoids the risks that come with oestrogen. That is the key difference between the mini pill and the contraceptive pill most people know, the combined pill, which adds oestrogen to the progestogen and stops ovulation reliably.

Australian Types and Their Late Dose Windows

Three types are sold in Australia, all only available on prescription. Levonorgestrel and norethisterone types are taken every day with no breaks, and a dose counts as late if it is more than 3 hours after your usual time. The drospirenone type has 24 hormone tablets and 4 hormone free tablets in each pack, taken without a gap, and a dose counts as late after 24 hours. Taken correctly, each contraceptive type prevents more than 99 in 100 pregnancies over a year, and in everyday use about 93 in 100 people avoid pregnancy, much the same as the combined pill. If headaches, spotting or the timing do not suit you, another contraceptive, such as the implant or a hormonal IUD in the womb, may suit better than stopping contraception altogether. Ask your doctor which mini contraceptive pill fits your routine, and keep the leaflet for the hormone rules of your own brand.

How to Treat Mini Pill

Managing the progestogen-only pill comes down to routine. Take one progestogen-only pill at the same time every day, set a phone alarm, and start the next pack straight after the last one, with no break. If you start a traditional type on the first to fifth day of your period, or the drospirenone type on the first day, it works straight away; otherwise use condoms for the first 2 days with a traditional type, or 7 days with the drospirenone type.

Bleeding on any mini contraceptive pill is the main thing people need to manage. Many have unpredictable spotting in the first months, some have regular periods and some have none, and all of these patterns are harmless. If bleeding on the progestogen-only pill bothers you, a doctor can check for other causes, such as an infection, and may suggest a different progestogen-only pill, or the combined pill if it suits you.

Keep taking it when you are unwell, but vomiting within 3 hours of a tablet, or severe diarrhoea, counts as a missed tablet. Tell any doctor or pharmacist that you take a progestogen-only pill, as some medicines for epilepsy, HIV and tuberculosis, and the herbal remedy St John's wort, make it less effective. A contraceptive implant or IUD may suit better if daily timing is hard.

What to Do After a Late or Missed Dose

If a tablet is late beyond its window, more than 3 hours for a traditional type or 24 hours for drospirenone, take it as soon as you remember, even if that means two in one day, and take the next one at the usual time. Use condoms or avoid sex until you have taken tablets on time for 2 days with a traditional type, or 7 days with drospirenone, because the hormone needs that long to thicken the mucus at the cervix again and stop sperm. If you had sex in the days before the late tablet, an emergency contraceptive may be needed, so speak to a pharmacist or your GP straight away. The rules differ from those for the combined pill, so check the leaflet for your own pill. A late tablet can also bring on some bleeding as the lining of the uterus reacts, which is not harmful.

Progestogen Only Versus Combined Contraception

Both are reliable contraception when taken as directed, and the choice usually comes down to oestrogen. The combined pill contains oestrogen as well as a progestogen, which gives more predictable bleeding, can ease heavy or painful periods and acne, and allows 24 hours for a late pill, but it is not safe for everyone. Progestogen only contraception avoids oestrogen, so it suits more people, including those breastfeeding, but periods are less predictable and the traditional types have a short window. Both work partly at the cervix by thickening mucus, and breast tenderness can happen on either. Neither protects against sexually transmitted infections, so condoms matter with new partners.

Both forms of contraception need a prescription, and a doctor can help you weigh which fits your health and routine, or whether a longer acting contraceptive, such as the implant, would be easier.

Bleeding or Symptoms That Need a Doctor

Some irregular bleeding is expected, but see a doctor for bleeding that is very heavy, lasts more than a week, comes after sex, or starts after months of a settled pattern, as these can have other causes, such as an infection or a problem in the uterus. Seek care promptly for a breast lump, severe headaches that are new or different, or yellowing of the skin.

Severe pain low in the tummy or on one side, especially with a missed period or bleeding, can mean a pregnancy outside the uterus, where a fertilised egg grows outside the womb; go to an emergency department, or call 000 if you feel faint. If bleeding does not settle after a few months, the doctor may suggest a different contraceptive, or the combined pill if it suits you.

Side Effects and the Ectopic Pregnancy Risk

Side effects of this pill are usually mild: changes in your periods, breast tenderness, mood changes, acne and, less often, nausea. Most settle within three months, and there is no good evidence that it causes weight gain.

Any contraceptive pill greatly lowers the chance of pregnancy, so an ectopic pregnancy, where the egg implants outside the womb, usually in a fallopian tube, is rare on it. If a pregnancy does happen on a traditional type, though, it is slightly more likely to be ectopic, because the progestogen slows the egg's movement along the tube and the traditional types do not reliably stop it being released.

An ectopic pregnancy needs urgent care. Do a pregnancy test if your period is late after a regular pattern, and seek care at once for one sided tummy pain, shoulder tip pain or fainting. If you have had an ectopic pregnancy before, your doctor may suggest another contraceptive.

Summary

The mini pill is a reliable, oestrogen free option when taken on time. This guide covered the types, timing, late doses, bleeding and side effects. If you are wondering whether the mini pill suits you, a Medio doctor can give advice by phone and, where the doctor thinks it right, send an eScript or a referral.

Frequently asked questions

What are the pros and cons of using the mini pill?

The benefits of the progestogen-only pill are that it has no oestrogen, suits people who are breastfeeding or cannot take the combined pill, and is highly effective when taken on time; the main difference between it and the combined pill is the missing oestrogen. The drawbacks are unpredictable bleeding and, for the traditional types, a 3 hour window for a late dose.

What is the mini pill birth control called?

Its proper name is the progestogen only pill, or POP. Overseas it is often called the progestin only pill, and some people say progesterone only pill. In Australia it comes as levonorgestrel, norethisterone or drospirenone tablets, all only available on prescription.

Can a doctor help with mini pills?

A Medio doctor can help by phone: they check your health history, other medicines and whether a progestogen suits you and, where the doctor thinks it right, send an eScript. Your pharmacist can explain how to take it, and either can tell you where to get the combined pill or POP if you switch.

Do you gain weight on the mini pills?

Studies have not shown that progestogen only tablets cause weight gain. Some people notice changes in appetite or bloating, which usually settle. If your weight changes a lot, talk to your doctor, because another cause is more likely.

What is the weakest birth control pill?

No pill is weak when taken correctly: the traditional progestogen only types work as well as the combined pill with perfect use. They are the least forgiving of a late dose, with a 3 hour window, so in everyday use, taking it on time decides how effective any pill is.

Who should not take the Pill?

The combined pill is not safe for people who get migraine with aura, have had a blood clot or stroke, smoke and are over 35, have high blood pressure or some liver and heart conditions, or are in the first weeks after giving birth. Most women in those groups can use the progestogen only form instead; a doctor checks which suits you.