Norethisterone for Delaying Menstruation
Yes, norethisterone can effectively delay menstruation when taken continuously until the desired date when menstruation should occur. 1
Mechanism and Efficacy
Norethisterone is a progestin that works by maintaining the endometrium in a secretory state, preventing menstrual shedding while the medication is being taken. 1 When used for menstrual delay, the medication should be started 3-5 days before the expected onset of menstruation and continued without interruption until menstruation is desired. 1
The typical dosing regimen is 5 mg orally two to three times daily, starting 3 days before the expected period and continuing until menstruation is desired. 2 Menstruation typically occurs 2-3 days after discontinuation of norethisterone. 3
Clinical Evidence
Research demonstrates that norethisterone effectively controls menstrual timing:
- In IVF cycle timing studies, menstruation occurred 2-3 days after norethisterone cessation as planned in 82% of patients overall, and in 87% of patients with regular cycles. 3
- The medication does not suppress estradiol levels below normal follicular phase ranges, allowing for physiologic hormonal function while preventing menstruation. 4
- When used for menstrual cycle control, norethisterone maintains its effectiveness without compromising subsequent reproductive function. 3
Contraindications - Critical Safety Considerations
Norethisterone is absolutely contraindicated in the following conditions: 1
- Pregnancy - must be excluded before initiating treatment 1
- History of thromboembolism or deep vein thrombosis - significant risk of recurrence 1
- Undiagnosed vaginal bleeding - requires investigation before hormonal manipulation 1
- Active liver disease - impaired metabolism and hepatotoxicity risk 1
- Breast cancer or other hormone-sensitive cancers - progestin may stimulate tumor growth 1
- Uncontrolled hypertension - cardiovascular risk amplification 1
Additional relative contraindications include smoking in women over 35 years, cerebrovascular disease, coronary artery disease, and hypercoagulopathies. 2
Practical Implementation Algorithm
Step 1: Screen for contraindications
- Obtain pregnancy test if any possibility of pregnancy 1
- Review personal and family history of thromboembolism 1
- Assess blood pressure 2
- Evaluate for undiagnosed bleeding patterns 1
Step 2: Timing and dosing
- Start norethisterone 5 mg orally 2-3 times daily 2
- Begin 3 days before expected menstruation 3
- Continue without interruption until menstruation is desired 1
Step 3: Patient counseling
- Menstruation will occur 2-3 days after stopping medication 3
- Breakthrough bleeding may occur but is uncommon with proper dosing 3
- This is not a contraceptive method - additional contraception needed if sexually active 2
Common Pitfalls and Caveats
Starting too late: Norethisterone must be initiated before menstruation begins. If bleeding has already started, the medication will not be effective for that cycle. 3
Inadequate dosing: Lower doses (0.5-1.5 mg daily) may not reliably suppress menstruation and can result in breakthrough bleeding or failed cycle delay. 5 The standard 5 mg dose 2-3 times daily is necessary for reliable menstrual suppression. 2
Irregular baseline cycles: Women with highly variable cycle lengths (>2 days variation) have lower success rates (82% vs 87%) in achieving predictable menstrual timing. 3 These patients should be counseled about potentially reduced efficacy.
Duration limitations: While norethisterone can be used for short-term menstrual delay (days to weeks), it is not intended for long-term continuous suppression without medical supervision. 1 For repeated or prolonged use, alternative hormonal management should be considered. 2
Not a contraceptive: Norethisterone at doses used for menstrual delay does not reliably inhibit ovulation and should not be relied upon for contraception. 5 Patients who are sexually active require separate contraceptive methods.