Mifepristone: Uses, How It Works & Side Effects

Medicines

Mifepristone is the first of the two medicines used in a medication abortion. This guide explains what mifepristone is, how it works in the body, its medical uses, side effects, who should not take it, and how it differs from misoprostol. It is written for readers in Riyadh and across Saudi Arabia.

Medically reviewed by Dr. Bhimi Daimari MS (Obstetrics and Gynaecology) · Reg. No. 23218 (Assam Council of Medical Registration)
Published: October 23, 2026 · Last reviewed: October 23, 2026

What Is Mifepristone?

Mifepristone tablet illustration for medication abortion guide

Mifepristone is a prescription medicine that blocks the hormone progesterone. Doctors classify it as an antiprogestogen. It is best known as the first medicine in a medication abortion, where it is used together with misoprostol.

It was first approved in France in 1988 and is now on the World Health Organization’s Model List of Essential Medicines, which lists the medicines a basic health system needs. It is sometimes known by its development code, RU-486.

How Does Mifepristone Work?

Progesterone keeps the lining of the uterus thick and supports a growing pregnancy. Mifepristone attaches to the body’s progesterone receptors and blocks them, so progesterone can no longer act.

1. Blocks progesterone

The hormone that sustains the pregnancy can no longer work.

2. Pregnancy stops developing

The lining breaks down and the pregnancy separates from the uterine wall.

3. Prepares the uterus

The cervix begins to soften and the uterus becomes more responsive to misoprostol.

Mifepristone on its own is much less effective at ending a pregnancy. Its main role is to prepare the body so that misoprostol works well.

Medical Uses of Mifepristone

Medication abortion in early pregnancy, together with misoprostol
Miscarriage management, to help the uterus empty after an early pregnancy loss
Before some procedures, to soften the cervix
Induction of labour after a pregnancy loss later in pregnancy
Cushing’s syndrome, a hormone disorder, where a different product and regimen are used

Each use has its own regimen, chosen by the treating doctor.

How Mifepristone Is Given

In a medication abortion, mifepristone is usually taken first, often at a clinic, after a medical assessment confirms how far along the pregnancy is and rules out an ectopic pregnancy. Misoprostol follows after an interval set by the clinician, commonly 24–48 hours.

The strength, number of tablets and timing are decided by the prescribing clinician. Do not change a prescribed regimen without medical advice. For the full process, read what happens step by step.

Read nextMisoprostol: Uses, How It Works and Side Effects

The second medicine in a medication abortion: what it does and its side effects.

Read guide →

Side Effects of Mifepristone

Most people feel little or nothing after mifepristone itself. The strong cramping and heavy bleeding of a medication abortion usually start after misoprostol.

Possible after mifepristone

Nausea
Light bleeding or spotting
Mild cramping
Headache or tiredness

Rare but serious

Allergic reaction: rash, swelling of the face or throat, difficulty breathing
Heavy bleeding before misoprostol is taken

For the full list of side effects and warning signs, read abortion pill side effects and safety.

Who Should Not Take Mifepristone?

A clinician should assess you first. Mifepristone is generally not suitable if you:

Have a confirmed or suspected ectopic pregnancy
Have chronic adrenal failure or take long-term corticosteroids
Have a bleeding disorder or take blood-thinning medicines
Have inherited porphyria
Have an IUD in place (it must be removed first)
Have had an allergic reaction to mifepristone

Tell your clinician about every medicine you take, including herbal products. Some medicines, such as certain antifungals and anticonvulsants, can change how mifepristone works.

Mifepristone vs Misoprostol

	Mifepristone	Misoprostol
Type	Antiprogestogen	Prostaglandin analogue
What it does	Blocks progesterone; stops the pregnancy developing	Softens the cervix and makes the uterus contract
Order	Taken first	Taken second, after an interval
How it feels	Usually little or nothing	Cramping and bleeding
Used alone?	Not for abortion	Sometimes, but less effective than combined
Other uses	Miscarriage, Cushing’s syndrome	Miscarriage, stomach ulcers, after-birth bleeding

Mifepristone in Saudi Arabia

Regulated medicine: mifepristone is regulated by the Saudi Food and Drug Authority (SFDA) and is not sold freely in pharmacies.
Restricted access: abortion is generally permitted only for medical reasons through authorized healthcare channels. See our legal overview.
Counterfeit risk: mifepristone sold online or through WhatsApp is often fake or the wrong strength. See how to spot fake pills.
Getting care in Riyadh: speak to a licensed doctor at an MOH hospital or authorized clinic, or call the MOH helpline on 937. For emergencies, call 997.

Frequently Asked Questions

What is mifepristone?

Mifepristone is a prescription medicine that blocks the hormone progesterone. It is used with misoprostol to end an early pregnancy and to manage some miscarriages.

What does mifepristone do?

It stops progesterone from supporting the pregnancy, so the pregnancy stops developing and separates from the uterine lining. It also makes the uterus more responsive to misoprostol.

Can mifepristone be used alone?

For ending a pregnancy, mifepristone is used together with misoprostol. On its own it is much less effective.

What are the side effects of mifepristone?

Most people feel little after mifepristone itself. Some have nausea, light bleeding, headache or tiredness. Stronger cramping and bleeding come after misoprostol.

Is mifepristone available in Saudi Arabia?

Mifepristone is a regulated medicine and is not sold freely. Abortion is generally permitted only for medical reasons through authorized healthcare channels.