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Mini Pill: What You Need to Know About the Progestin-Only Birth Control

Mary Lucas, RN

Medically reviewed by Mary Lucas, RN

Written by Our Editorial Team

Last updated 10/27/2020

You’re not ready to be a mom — maybe you just had a baby or perhaps you never want to have one. Whatever the reason, you have a slew of contraception options. 

The mini pill, or progestin-only birth control, is one of many options for preventing pregnancy. Unlike combination pills, the mini pill does not contain estrogen. 

For some women who have tried estrogen-containing pills and experienced side effects, the mini pill may be a better fit. But without estrogen, you may still get a regular period and possibly still ovulate. 

Taking the mini pill requires strict adherence to dosing times, but that doesn’t mean it may not be a good fit for you.If you’re considering going on the progestin-only mini pill, read on to find out everything you need to know before you begin. 

The Basics, In Short 

  • The mini pill is often referred to as a “progestin-only” birth control pill because it doesn’t contain estrogen as traditional combination pills do. 

  • The mini pill works to prevent pregnancy primarily by thickening the cervical mucus and thinning the endometrial (uterine) lining. 

  • Most women still ovulate while on the mini pill. 

  • Most women still experience regular periods while on the mini pill. 

  • Breakthrough bleeding is common for the first several months of taking any birth control pill and should lessen as time goes on. 

  • The incidence of breakthrough bleeding or disruptive periods is more common with the mini pill. 

  • Taking your mini pills at exactly the same time each day can lessen the risk of spotting and accidental pregnancy. 

  • Because the mini pill doesn’t contain estrogen, women who have experienced disruptive side effects with combination (estrogen-containing) pills may have better luck with the mini pill. 

  • Progestin-only pills are safe for use by nursing mothers. 

How Mini Pill Birth Control Works 

Mini pills prevent pregnancy in two main ways: by thickening the cervical mucus to prevent the passage of sperm through it and by thinning the lining of the uterus to prevent the attachment of a fertilized egg. 

These progestin-only pills may also prevent ovulation, but not consistently. Stopping ovulation is the primary way combination birth control pills work, but some women on mini pills may still ovulate. That’s why it’s more important than ever that you take the mini pill at the same time every day. 

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Mini Pill Contraceptive Effectiveness 

The effectiveness of the mini pill depends on when you start it and how consistently you take it. 

If you start it within the first five days of starting your period, it’s immediately effective. 

If you start it more than five days from the first day of your period, you should use a backup method, such as a condom, for at least the first two days, according to the Centers for Disease Control and Prevention

Taking your mini pill at the same time each day increases its effectiveness. Overall, the risk of pregnancy is about two percent to three percent while on the mini pill. 

However, taking it regularly can reduce this risk, while  forgetting a pill or taking it at inconsistent times can increase this risk.

Oral contraceptives, including the mini pill, do not prevent the spread of sexually transmitted infections.

Periods While On Progestin-Only Birth Control

Because progestin-only birth control pills do not stop ovulation consistently, you may still have a regular period while on them

Unlike combination birth control, there are no “inactive” pills in a progestin-only packet — all of the pills are identical. 

So, it’s doubly important you continue to take the mini pills while you’re on your period. 

Because mini pills do affect your hormone levels, you may experience changes in your period. 

They could become heavier or lighter than normal, and occasionally you may skip a period. 

As many as half of women on the mini pill experience longer menstruation

One of the drawbacks of the mini pill is irregular bleeding, but expecting this can help you manage it when it happens. 

Spotting Between Periods While on the Mini Pill 

As with any birth control pill, spotting can be common in the first several months of starting the mini pill. This should decrease or completely subside once your body gets accustomed to the medication. However, spotting while on the mini pill is not completely unusual and is generally not something to be concerned about. 

Spotting while on the progestin-only pill may be more common than while on estrogen-containing combination pills — an estimated 70 percent of women on progestin-only pills experience spotting. 

Because of this, bleeding “disturbances” are the most common reason women stop taking the mini pill.

Mini Pill Side Effects 

As with any medication, the mini pill comes with potential side effects. It’s highly unlikely you’ll experience all of them, but knowing they’re possible can help you prepare. 

Spotting and irregular bleeding is perhaps the most disruptive side effect of the mini pill, but weight gain, breast tenderness, headache, acne and nausea are all possible. 

Advantages of the Mini Pill 

Some women opt for the mini pill over estrogen-containing pills after having negative side effects with the latter. 

Without estrogen, the mini pill is an effective contraceptive solution for women who don’t tolerate estrogen well. 

Estrogen-containing pills can worsen migraines in some women and increase the risk of blood clots. 

Mini pills may also lessen the intensity of menstrual cramps.

Also, progestin-only birth control pills do not interfere with breastfeeding, so nursing mothers can take them without concern for their little ones. 

Mini Pill Options and Brand Names 

There are numerous mini pill brand names currently on the market. The generic name for progestin-only pills is norethindrone. Brand names include: 

  • Micronor®

  • Camila®

  • Errin®

  • Jolivette®

  • Nor-Q.D.®

  • Jencycla ®

The Bottom Line on the Mini Pill 

The progestin-only mini pill is one of several options for women wishing to prevent pregnancy. It’s especially a good fit for women who are breastfeeding or who have had side effects with traditional, combination birth control pills. 

Because the mini pill doesn’t contain estrogen, you may experience greater disruption to your periods than you would on combination pills. Taking the mini pill at the same time each day can lessen this risk and the likelihood of an unexpected pregnancy. 

If you decide to try or switch to the mini-pill, it’s important to remember that it only works effectively if you take it consistently at the same time every day — if you miss a mini-pill by more than three hours, you have to use an alternate form of contraception until your next period. 

As with all forms of birth control, it has its upsides and downsides, but if it’s something you’re into, it’s safe, effective and used by millions of women every day. 

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.