SKIP AHEAD. . .
What is Norethindrone?
Norethindrone is the generic name for the synthetic hormone progestin (meant to mimic the naturally-occuring hormone progesterone), which helps regulate the menstrual cycle. It is often used in both combined and progestin-only contraceptives because it thickens the lining of the uterus and changes cervical mucus to prevent pregnancy (1).
It’s most commonly prescribed as a contraceptive, but can also be used to treat secondary amenorrhea (the absence of a menstrual period in people who used to have consistent periods and are not pregnant or going through menopause), endometriosis, Polycystic Ovarian Syndrome (PCOS), and irregular menstrual periods caused by hormonal imbalance (2).
How does Norethindrone work?
Norethindrone has multiple effects: it acts to thicken cervical mucus, thin the uterine lining by encouraging shedding and stopping it from growing (3) and suppress ovulation (the release of an egg from an ovary) in about half of users (1). As such, it makes pregnancy much more difficult: it’s less likely that an egg would be released from the ovary in the first place, but its also more difficult for sperm to reach the egg to fertilize it, and then harder still for a fertilized egg to attach itself to the uterus, even if fertilization were to somehow occur (4). A three-pronged line of defense!
Norethindrone is a progestin-only form of contraception, and so many healthcare providers will prescribe it for people who don’t want a contraceptive that contains estrogen (such as the combined pill, contraceptive patch or vaginal ring). You can use this pill when breast/chestfeeding, but if you are a cigarette smoker you should avoid it (2). Norethindrone may also be prescribed if you (or someone in your family) have had blot clots, as other forms of contraception may not be considered safe for those who have a history.
Because Norethindrone stops the uterine lining from growing, it’s often prescribed for hormonal disorders like Polycystic Ovarian Syndrome (PCOS) and endometriosis. Endometriosis occurs when the tissue that grows in the lining of the uterus grows in other areas of the body and causes pain, irregular bleeding or other menstrual symptoms. Since Norethindrone prevents the uterine lining from growing, it prevents this same tissue from growing elsewhere in the body. PCOS causes you to have low levels of progesterone, so Norethindrone is often prescribed to increase progesterone levels and thereby improve the regularity of periods (1).
Norethindrone doesn’t protect you against STDs/STIs, nor does it solve for any root causes of PCOS or endometriosis.
How do I take Norethindrone?
Norethindrone is usually taken as a tablet by mouth. It comes under a range of brand names (such as Camila, Aygestin, Norlutate). If you’re taking Norethindrone as a contraceptive, you may hear it referred to as the “mini-pill” – this is distinct from “the pill” which is the term used to refer to the ‘combined pill’ (which contains synthetic versions of both estrogen and progesterone). The mini pill (Norethindrone) doesn’t contain estrogen like the combined pill,
You can’t get Norethindrone over the counter without a prescription (though some states are beginning to allow pharmacists to prescribe certain forms of birth control, yay!), so your healthcare provider will give you instructions about the recommended brand and dosage. The brand name, dosage, and frequency may differ depending on the reason Norethindrone has been prescribed to you.
It’s important to remember to take Norethindrone at the same time every day (1). Pick a time that’s most convenient for you so that it’s easier for you to remember and keep consistent. If you’re taking Norethindrone as a contraceptive, remember that every pill is “active”: this means that every pill contains progestin and none of them are simply sugar/placebo pills like you get in combination pill packs. If you miss a pill, take it as soon as you remember. If you take a pill more than 3 hours late, it may not be effective in preventing pregnancy (1), so use a back up method such as condoms or spermicide for the next 48 hours. More on missing your pills here!
If taken correctly, Norethindrone is 99% effective. However, with “typical use” (the way it’s usually taken in real life) it’s more like 92% effective (4).
Synthetic hormones affect everyone differently. Most side effects occur during the first few months of use and then go away or settle down. However, if you notice anything unusual, or you feel that your side effects are uncomfortable or in any way unbearable, it’s always best to visit your healthcare provider for peace of mind, or to change up your birth control.
Some of the known side effects of taking Norethindrone are (2):
- irregular vaginal bleeding or spotting
- changes in menstrual flow
- enlarged or tender breasts
- upset stomach
- weight changes
- difficulty falling asleep or staying asleep
- growth of hair on face
Can I use Norethindrone to stop my period?
A known side effect of Norethindrone among some people is that their periods become lighter, shorter, or stop altogether. This is considered a side effect rather than the intended purpose for taking Norethindrone.
How long does it take to start working?
If you’re taking Norethindrone in order to prevent pregnancy, you can start taking the pills on any day of your cycle and they will start to take effect within 48 hours (4). During this time you should make sure to use an alternative form of contraception in order to be protected against pregnancy.
However, if you are prescribed Norethindrone for other conditions (such as endometriosis or irregular bleeding) it will likely take longer for its effects to be noticeable. Your healthcare provider will be able to provide a more accurate estimate (based on the brand, dosage and frequency) when they prescribe Norethindrone.
Written by: Rachel Besenyei, writer interested in womxn’s health and pain. Rachel is based in London, UK, and you can find her at @rachelbesenyei.
Medically reviewed by: Aisha Wagner, MD. Family Physician with fellowships focusing on contraception and abortion advocacy
All content found on this Website, including: text, images, audio, or other formats, was created for informational purposes only. The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
- “Progestin-Only Oral Contraceptives: MedlinePlus Drug Information.” MedlinePlus. U.S. National Library of Medicine, January 15, 2016. https://medlineplus.gov/druginfo/meds/a602008.html.
- “Norethindrone (Oral Route) Side Effects.” Mayo Clinic. Mayo Foundation for Medical Education and Research, July 1, 2019. https://www.mayoclinic.org/drugs-supplements/norethindrone-oral-route/side-effects/drg-20137986?p=1.
- “Norethindrone: MedlinePlus Drug Information.” MedlinePlus. U.S. National Library of Medicine, May 15, 2016. https://medlineplus.gov/druginfo/meds/a604034.html.
- “The Progestogen-Only Pill.” NHS. National Health Service UK, January 8, 2018. https://www.nhs.uk/conditions/contraception/the-pill-progestogen-only/.
- “How Can I Delay My Period?” NHS. National Health Services UK, January 7, 2019. https://www.nhs.uk/common-health-questions/travel-health/how-can-i-delay-my-period/.