The most commonly prescribed progestin for delaying a period is norethisterone (norethindrone), taken at 5 mg three times daily. You start about three days before your expected period and continue taking it for as long as you need the delay. Your period will typically arrive two to four days after you stop.
That said, different forms of progesterone come in very different dosages, and the amount you need depends on whether you’re trying to delay an upcoming period, stop one that’s already heavy, or suppress periods longer term. Here’s how it breaks down.
How Progesterone Prevents Your Period
Your uterine lining builds up each month under the influence of estrogen. Progesterone’s job is to stabilize that lining. During the second half of your cycle, your ovaries naturally produce progesterone, which stops the lining from growing further and prepares it to either support a pregnancy or shed in a controlled way. When progesterone levels drop at the end of your cycle, the lining loses its hormonal support and breaks down. That breakdown is your period.
When you take a progestin medication, you’re essentially keeping progesterone levels artificially high. The lining stays stable and intact, so there’s nothing to shed. The moment you stop taking the medication, levels drop and a withdrawal bleed follows, usually within two to four days.
Standard Doses for Delaying a Period
Norethisterone at 5 mg three times a day is the standard regimen for short-term period delay. You begin three days before your period is due and take it continuously until you’re ready for your period to arrive. In clinical comparisons, norethisterone outperformed combined oral contraceptive pills for preventing breakthrough bleeding during the delay, and 80% of users in one study said they’d choose this method again.
A controlled-release version of norethisterone acetate uses a slightly different dosing range of 10 to 15 mg per day, depending on the specific indication. The controlled-release form keeps steadier drug levels in the blood, which can mean fewer side effects and no need to remember a dose in the middle of the night.
If you’re already on a combined birth control pill, skipping the placebo week and starting the next active pack is another common way to skip a period, though breakthrough spotting is more likely with this approach than with norethisterone.
Doses for Stopping Heavy or Active Bleeding
Stopping a period that has already started, especially one with heavy bleeding, requires much higher doses than simply delaying one. The medications used are the same progestins, but at several times the preventive dose.
Medroxyprogesterone acetate (MPA) is the most studied option for acute heavy bleeding. Typical protocols include:
- Moderate approach: 20 mg three times daily for seven days, then reduced to 20 mg once daily for another three weeks.
- High-dose taper: 60 to 120 mg on the first day, followed by 20 mg daily for nine more days. In a study of hospitalized adolescents, every patient stopped bleeding within four days on this regimen.
- European protocol: 10 mg every four hours, up to 80 mg per day, with a gradual taper.
These high-dose protocols are used in clinical settings for heavy or dangerous bleeding, not for routine period management. They’re worth knowing about if you’ve been told you need to stop active bleeding for a medical reason, but they aren’t something to try on your own.
Micronized Progesterone vs. Synthetic Progestins
Not all progesterone is the same. Micronized progesterone is bioidentical, meaning its molecular structure matches the progesterone your ovaries produce. Synthetic progestins like norethisterone and medroxyprogesterone have different chemical structures, which makes them more potent at smaller doses but also gives them a slightly different side effect profile.
Micronized progesterone is typically prescribed at much higher milligram doses (up to 300 mg daily in some clinical trials) because it’s less potent milligram-for-milligram than synthetic options. It’s more commonly used in hormone therapy for menopause than for period delay. One notable advantage: micronized progesterone doesn’t appear to negate the heart-protective effects of estrogen the way synthetic progestins can, and observational studies suggest it carries a lower breast cancer risk when used alongside estrogen in menopause therapy.
For the specific purpose of delaying or stopping a period, synthetic progestins like norethisterone are the go-to because they’re effective at lower doses and have more clinical data behind them for this use.
Longer-Term Period Suppression
If your goal is to suppress periods for months rather than days, other progestin-based options exist. These include hormonal IUDs that release a small daily dose of progestin directly into the uterus, injectable progestins given every three months, and continuous-use birth control pills. All of these work on the same principle of keeping the uterine lining thin and stable so there’s little to shed.
The tradeoff with longer-term suppression is that irregular spotting or breakthrough bleeding is common in the first one to three months. This gets better over time, and by the end of the first year most methods have similar rates of successfully stopping periods. For some people, it can take up to a year for spotting to fully resolve.
Side Effects of Short-Term Use
The most common side effect of any progestin used for period management is irregular or unscheduled bleeding, which is somewhat ironic when the whole point is to control bleeding. Spotting is especially likely if you start the medication too late in your cycle or use a dose that’s lower than recommended.
Other reported side effects during short-term use include bloating, breast tenderness, headaches, and mood changes. Nausea is possible but uncommon. In a study of adolescents taking high-dose medroxyprogesterone (60 to 120 mg on day one), none reported bothersome nausea or vomiting.
Who Should Avoid Progestins
Age, body mass index, and family history of blood clots are independent risk factors that increase your chance of a thromboembolic event while using hormonal therapy. Progestins are generally safer than combined estrogen-progestin products on this front, but they’re not risk-free. If you smoke 15 or more cigarettes a day and are 35 or older, hormonal options are typically contraindicated. A history of blood clots, certain liver conditions, or hormone-sensitive cancers may also rule out progestin use.
What to Expect When You Stop
After you stop taking a progestin for period delay, expect a withdrawal bleed within two to four days. This bleed is usually similar to a normal period in length and heaviness, though some people find it slightly lighter or heavier than usual. Your next natural cycle should resume on its own after that, with your regular period returning roughly on schedule one month later. Short-term use of progestins for a single cycle does not affect long-term fertility.