Norethindrone (Aygestin) for Endometriosis: What to Expect

Aygestin is a brand name for norethindrone acetate 5 mg, a progestin tablet that the FDA has approved to treat endometriosis. In endometriosis, it acts like the hormone progesterone and stops the lining of the uterus from growing, which can ease period pain and pelvic pain.

If your doctor has just prescribed norethindrone 5 mg, this guide covers how it works, the side effects, what spotting and mood changes can look like, and what to write down each week. It also answers a common question about delaying a period for a trip. It is general information and not medical advice. Your own doctor decides what is right for you.

For a comparison of all the main treatments, see our guide to endometriosis treatment options. This page is only about norethindrone acetate 5 mg.

What Aygestin is and what it treats

Aygestin is one brand name for norethindrone acetate. The same medicine is also sold as a generic tablet, norethindrone acetate 5 mg. Its other name is norethisterone acetate.

The US label lists three uses:

• Endometriosis
• Periods that have stopped for months when you are not pregnant (secondary amenorrhea)
• Abnormal bleeding from a hormone imbalance, when no fibroid or cancer causes it

For endometriosis, the usual schedule starts at 5 mg a day for two weeks. It then goes up by 2.5 mg a day every two weeks, to 15 mg a day. Treatment can stay at that level for 6 to 9 months, or until breakthrough bleeding is a problem. Your doctor will probably start you on a low dose and raise it no more than once every 2 weeks. Take it exactly as your prescription says.

Norethindrone may control endometriosis but will not cure it. Keep taking it even when you feel well, and talk to your doctor before you stop.

Aygestin 5 mg is not the 0.35 mg birth control pill

Norethindrone is also the hormone in the progestin-only birth control pill, often called the minipill. The two tablets have different jobs:

The minipill has 0.35 mg of norethindrone in each tablet, and its only labelled use is to prevent pregnancy. Norethindrone is taken in smaller amounts when it is used to prevent pregnancy. The body turns norethindrone acetate into norethindrone, and by weight the acetate is about twice as strong.

So a 5 mg tablet is a much bigger dose than a minipill. Do not swap one for the other, and check the strength on your pack.

How norethindrone works in endometriosis

Norethindrone acetate is a man-made progestin, similar to the progesterone your body makes. Endometriosis is tissue like the lining of the uterus that grows in other areas of the body. The medicine stops the lining of the uterus from growing.

Progestogens are a first choice for this pain. Doctors should prescribe progestogens to reduce endometriosis pain, and think about the different side effects of each one when they choose. Stronger hormone-lowering medicines, such as Orilissa or Lupron, are a second-line choice because of their side effects. Dienogest (Visanne) is another progestogen, sold outside the US.

How well does it work

A small 2025 trial compared norethindrone acetate 5 mg a day with dienogest 2 mg a day in 70 people with endometriosis. It found:

• Pain. Period pain and pelvic pain went down in both groups at 6 and 12 months. There was no clear difference between the two medicines.
• Staying on it. By 6 months, 23.3% had stopped norethindrone acetate, against 47.5% on dienogest.
• Endometriomas. Ovarian cysts from endometriosis (endometriomas) shrank more on norethindrone acetate.

The trial was small, and only about half of each group finished 12 months. Treat these results as a guide, not a promise. The medicine does not work for everyone, and a lack of change is useful news for your doctor.

Common side effects

Common side effects are:

• Headache
• Breast pain
• Irregular bleeding or spotting
• Stomach cramps or bloating
• Nausea and vomiting
• Hair loss

Other possible side effects include weight changes, trouble sleeping, acne, brown patches on the face and hair growth on the face. Fluid retention, high blood pressure and high blood sugar can also happen. If you have diabetes or high blood fats, your doctor should check you more closely.

Tell your doctor if a side effect is severe or does not go away.

Breakthrough bleeding and spotting

Breakthrough bleeding, spotting, a change in flow and no periods can happen. Some people bleed on and off. Others stop having periods.

Breakthrough bleeding can also set how long you stay on it. Treatment usually lasts 6 to 9 months or until breakthrough bleeding becomes bothersome. Keep a note of the dates and how heavy the bleeding is. Tell your doctor about any irregular bleeding, because they may want to check for other causes.

Mood changes

Mood swings and depression are side effects of progestins. If you have had depression before, your doctor should watch you carefully. The medicine should stop if depression comes back and is serious.

Tell your doctor before you start if you have had depression. Call them if you notice new low mood or mood swings. Our article on endometriosis, depression and anxiety has more on how pain and mood link.

How long before you can judge it

Give it time before you decide. On the usual schedule, the dose goes up every two weeks and reaches 15 mg a day after about 8 weeks. In the trial above, pain was first checked at 6 months.

A fair first check is about 3 months after you start. By then you have had some weeks at a steady dose, and your notes cover several weeks of bleeding and pain. Ask your doctor when they want to review how it is going. See them sooner if side effects are hard to live with.

What to track week by week

Pain, bleeding and mood, written down once a week.

A short weekly note answers one question for you and your doctor: is the pain relief worth the side effects? A symptom diary helps to make pain clear and lets you show your symptoms. Before you start, write down one week of your usual symptoms if you can. It gives you something to compare with.

Each week, write down:

• Pain score. Your usual and worst pain from 0 to 10, on bleeding days and other days. Add what the pain stopped you doing.
• Bleeding. Which days you had spotting, and which days you needed a pad or tampon.
• Dose. Your daily dose, the date it changed and any missed tablets.
• Mood. How many days you felt low, anxious or irritable.
• Sleep. How many nights were poor.
• Side effects. Headache, breast pain, bloating, nausea, weight change, acne or anything new.
• Rescue pain relief. Which painkillers you took and how often. Less use is a sign that the medicine helps.

For help with the pain score, see how to describe period pain.

Endolog is a pain and symptom diary for endometriosis. You log pain, bleeding, other symptoms and notes on the days they happen, and you have a record to show at your review. A paper notebook works too.

Can norethindrone delay a period for a trip?

Yes, in the UK it is licensed for this. It is a different use from endometriosis treatment. The US label does not list delaying a period as a use. It lists only the three uses above. A doctor may still prescribe it for other uses.

Norethisterone is the UK name for norethindrone. It is the only progestogen licensed to delay periods. The UK advice is:

• Dose. Norethisterone 5 mg, three times a day.
• When to start. At least 3 days before your period is due.
• How long. Up to 3 to 4 weeks if needed.
• After you stop. Your period usually comes back within 3 days.
• Contraception. It is not a contraceptive, so use another method to avoid pregnancy.

If you already take norethindrone acetate every day for endometriosis, you may not have periods at all, or you may spot. Do not change your dose for a trip on your own. Ask your doctor first. Also tell them if you have ever had a blood clot, because the tablets must not be used after a clot, stroke or heart attack.

Who should not take it

Norethindrone acetate must not be used if you:

• Are pregnant or could be pregnant
• Have vaginal bleeding that has no known cause
• Have or have had breast cancer
• Have had a blood clot, stroke or heart attack
• Have liver disease or poor liver function
• Have had an allergic reaction to the tablets

It is also not for people who are postmenopausal or breastfeeding. Tell your doctor if you smoke, or if you have high blood pressure, diabetes, high cholesterol, migraine, seizures, lupus, or heart or kidney disease. These can raise the risk of serious side effects or need closer checks. St John's wort may interact with norethindrone, so tell your doctor about every medicine and supplement you take.

Pregnancy and contraception

The 5 mg label does not list birth control as a use. It must not be taken in pregnancy, because it may harm an unborn baby. Ask your doctor which contraception to use while you take it. If you think you could be pregnant, call your doctor right away.

When to call a doctor

Call 911 or your local emergency number now if you have:

• Chest pain, shortness of breath or coughing up blood
• Slow or unclear speech, or weakness or numbness in an arm or leg
• Trouble breathing or swallowing, or swelling of the face or throat

These symptoms need help at once. Blood clots from progestins can block blood flow to the lungs, heart or brain, and severe allergic reactions can also happen. Get help right away if you have thoughts of harming yourself. In the US, call or text 988.

Stop the tablets and call your doctor right away if you have:

• Sudden partial or complete loss of vision, blurred vision, bulging eyes, double vision or a migraine

Call your doctor right away if you have:

• Pain, warmth or heaviness in the back of your lower leg
• Dizziness or fainting, or a severe headache
• A breast lump
• Yellow skin or eyes
• Sudden, severe pain in your belly
• Swelling of your hands, feet or ankles
• Low mood or mood swings
• Heavy or long bleeding

These are among the warning signs of serious side effects that need a call to your doctor right away.

Talk to your doctor at your review if:

• Your pain has not gone down
• The side effects outweigh the relief
• The bleeding pattern still bothers you after the first few months

Frequently asked questions

What is Aygestin used for?

It is used for endometriosis, periods that have stopped, and abnormal bleeding from a hormone imbalance.

Is norethindrone 5 mg a birth control pill?

No. The birth control pill with norethindrone has 0.35 mg in each tablet. The 5 mg label does not list birth control as a use. Ask your doctor which contraception to use.

Will Aygestin stop my periods?

It can. No periods, spotting and breakthrough bleeding are all listed side effects. Because the tablets can stop your periods, a missed period will not warn you of a pregnancy. If you could be pregnant, do a test and call your doctor right away.

Does Aygestin cause weight gain?

It can change your weight up or down. It can also cause fluid retention and bloating.

How long can I take norethindrone for endometriosis?

Treatment at the full dose lasts 6 to 9 months, or until breakthrough bleeding is a problem. Your doctor may plan a different length. Talk to them before you stop.

What if I miss a dose?

Take it as soon as you remember. If it is almost time for the next dose, skip the missed one. Do not take a double dose.

This article is for general information. It is not medical advice and does not replace advice from your own doctor, who decides what treatment is right for you. If you think you have an emergency, call 911.