Missed Oral Progesterone Dose: Product-Specific Instructions

Editorial evidence status: This page was reconciled on August 29, 2026 to the current U.S. Prometrium DailyMed record and patient information marked Rev. 02/2026, MedlinePlus oral-progesterone instructions revised April 15, 2026, the current U.S. combined estradiol-progesterone label, NHS Utrogestan guidance, and systematic reviews of endometrial protection. Medical review is pending. It does not replace the instruction on a dispensed product or prescribe an individualized make-up dose.

Why One Internet Rule Cannot Cover Every Progesterone Capsule

“Progesterone capsule” can refer to different products, routes, combinations, and indications. Even when two products contain micronized progesterone, their approved formulations and patient instructions may differ. A missed dose during a finite course for secondary amenorrhea is also not the same decision as a missed dose in a cyclic menopause regimen, a continuous off-label regimen, or a fertility protocol.

The previous version of this page erased those distinctions. It asserted a same-evening cutoff, a morning skip rule, fixed hour windows, and a requirement not to extend a cyclic course. Those details are not stated in the current U.S. Prometrium label or established by a trial comparing missed-dose strategies.

The useful question is therefore not “What is the universal progesterone rule?” It is “Which instruction applies to the product and regimen actually dispensed?”

Instruction Provenance Matrix

This matrix is a source-control tool. It shows where each rule came from and prevents a nearby product's instruction from being relabeled as Prometrium evidence.

What the Current Prometrium Label Establishes

The current U.S. label covers two indications: prevention of endometrial hyperplasia in a postmenopausal woman with a uterus who is receiving conjugated estrogens, and treatment of secondary amenorrhea [1]. It specifies bedtime administration because some patients become very drowsy or dizzy. It also warns about driving or operating machinery until the effect is understood.

For labeled endometrial protection, the regimen studied was 200 mg daily for 12 days in each 28-day cycle with conjugated estrogens. In the label's 36-month trial, hyperplasia occurred in 6% of the combination group and 64% of the estrogen-only group [1]. That comparison explains why repeated omissions can matter when progesterone is the prescribed endometrial protection. It does not calculate the risk created by one missed capsule, establish a minimum safe number of days for every estrogen regimen, or prove how a missed day should be replaced.

The label also says that food increased Prometrium bioavailability in a pharmacokinetic study. It does not instruct every patient to take the capsule with a snack. This matters because the UK Utrogestan guidance says to take that product at least two hours after food, while the U.S. combination capsule says to take it with food [3,4]. “Progesterone plus food” is a product-specific instruction problem, not a sentence that can be safely copied between brands.

Prometrium contains peanut oil and is contraindicated for patients allergic to peanuts [1]. A compounded capsule may use another vehicle, but that difference is another reason to check the actual dispensed product rather than apply a brand rule by ingredient name alone.

A Practical Decision Path After a Missed Dose

1. Read the dispensed instruction first

Check the pharmacy label, manufacturer leaflet, and prescriber's written plan. If they provide a missed-dose instruction for the exact product, follow that instruction unless a clinician has since told you otherwise.

2. Confirm what was dispensed

Record the brand or compound, strength, route, whether estrogen is in the same capsule or taken separately, and whether the capsule is immediate-release or another preparation. Do not identify a product only as “bioidentical progesterone.”

3. Identify the treatment purpose and schedule

Determine whether the dose belongs to a finite secondary-amenorrhea course, cyclic endometrial protection, continuous menopause treatment, fertility care, pregnancy support, or another use. Record the scheduled day within the cycle, not only the number of hours late.

4. Do not double by default

MedlinePlus and NHS Utrogestan guidance both say not to take two doses to make up for one missed dose [2,4]. If the specific label or clinician plan is unclear, a pharmacist can interpret the product instruction without inventing a cutoff.

5. Escalate the questions the general rule cannot answer

Contact the prescriber or pharmacist when multiple doses were missed, the cyclic course may be shorter than prescribed, systemic estrogen is continuing, the indication is fertility or pregnancy care, the product is compounded, or the available directions conflict. The question should be explicit: take now, skip, add a day, restart the next scheduled course, or use a revised plan?

Missed-Dose Context Record

Use this record when a leaflet does not fully resolve the situation:

This record is the page's reproducible artifact. It does not calculate a dose; it captures the inputs required to apply the right instruction and documents where the answer came from.

Evidence Boundaries for Endometrial Protection

A 2016 systematic review concluded that oral micronized progesterone had evidence for endometrial protection when used sequentially at 200 mg daily for 12 to 14 days per month for up to five years [5]. A 2023 systematic review found that study quality and whether specific regimens met endometrial-safety criteria varied across progestogens and formulations [6].

Neither review randomized people to different responses after a missed capsule. They support the importance of the prescribed regimen; they do not establish that one missed dose produces a quantifiable loss of protection, that two missed doses create a 48-hour emergency, or that adding a fifteenth day can never be appropriate.

Do not use the label trial's group-level hyperplasia rate to forecast an individual's risk from one omission. The useful conclusion is narrower: when oral progesterone is paired with systemic estrogen for a person with a uterus, repeated missed doses or a shortened course deserve a prescriber-confirmed plan.

Claims This Page Does Not Make

• It does not claim that Prometrium has a 16-to-18-hour terminal half-life that determines a universal missed-dose cutoff; the current label reports highly variable concentration data but no such decision rule.
• It does not say that endometrial exposure becomes “negligible” after a fixed number of hours.
• It does not advise extending or refusing to extend a cyclic course without the prescriber's instruction.
• It does not transfer a UK food instruction, a combination-product cutoff, or a fertility protocol to U.S. Prometrium.
• It does not treat annual ultrasound or biopsy as routine monitoring for every user.
• It does not claim that a cited adherence study tested this progesterone regimen when it did not.

When the Problem Is More Than a Missed Dose

The current Prometrium patient information tells patients to seek prompt care for warning symptoms such as sudden severe headache, vision or speech changes, severe chest or leg pain with or without shortness of breath, dizziness or faintness, vomiting, or other unusual concerning symptoms [1]. Unusual vaginal bleeding also warrants contact with the healthcare provider.

Those situations should not be reduced to “take or skip.” Likewise, a clinician-directed hold around surgery, a product allergy, or severe dizziness after a dose requires the relevant safety plan rather than a generic adherence answer.