Which ICD‑10 diagnosis code should be used to document progesterone therapy based on its specific indication?

ICD-10 Diagnosis Codes for Progesterone Therapy Coverage

The specific ICD-10 code required to document progesterone therapy depends entirely on the clinical indication: use N95.1 for menopausal hormone replacement therapy, N91.2 for secondary amenorrhea, O20.0 for threatened miscarriage with prior pregnancy loss, or O09.291 for history of preterm birth when prescribing 17-hydroxyprogesterone caproate for preterm birth prevention. 1, 2, 3, 4

Primary Indications and Corresponding ICD-10 Codes

Menopausal Hormone Replacement Therapy (Most Common)

• N95.1 – Menopausal and female climacteric states: This code covers progesterone prescribed as endometrial protection in postmenopausal women receiving estrogen therapy. 3
• E28.310 – Symptomatic premature menopause: Use this code for women under age 40 with premature ovarian insufficiency requiring hormone replacement therapy with progesterone plus estradiol until at least age 51. 5, 6
• Progesterone is mandatory for all postmenopausal women with an intact uterus receiving estrogen therapy to prevent endometrial hyperplasia and cancer; the standard regimen is micronized progesterone 200 mg orally for 12–14 days per 28-day cycle. 3, 4
• The FDA label confirms that progesterone capsules 200 mg daily for 12 days per cycle reduced endometrial hyperplasia from 64% (estrogen alone) to 6% (combination therapy) over 36 months of treatment. 4

Secondary Amenorrhea

• N91.2 – Amenorrhea, unspecified: This code documents progesterone prescribed to induce withdrawal bleeding in premenopausal women with absent menses for ≥90 days. 4
• The FDA-approved regimen for secondary amenorrhea is progesterone capsules 300–400 mg daily for 10 days, which induced withdrawal bleeding in 73.8–80% of women within 7 days of the last dose. 4

Preterm Birth Prevention

• O09.291 – Supervision of pregnancy with history of pre-term labor, first trimester (use O09.292 for second trimester, O09.293 for third trimester): This code covers 17-hydroxyprogesterone caproate (17-OHP-C) prescribed for women with a singleton pregnancy and prior spontaneous preterm birth. 1, 2
• The Society for Maternal-Fetal Medicine recommends 17-OHP-C 250 mg intramuscularly weekly from 16–20 weeks until 36 weeks of gestation, which reduced recurrent preterm birth at <37 weeks from 54.9% to 36.3%. 1, 2
• Do not use vaginal progesterone for this indication in women with prior preterm birth; multiple randomized controlled trials showed no benefit, and the 2012 SMFM guideline explicitly recommends 17-OHP-C as the preferred agent. 1, 2

Threatened Miscarriage (First Trimester)

• O20.0 – Threatened abortion: This code documents vaginal micronized progesterone prescribed for first-trimester bleeding in women with a history of prior miscarriage. 7
• The 2021 NICE guideline recommends vaginal micronized progesterone twice daily in women with previous miscarriage who present with bleeding and have a viable intrauterine pregnancy; however, treatment should be stopped at 12 weeks of gestation (not 16 weeks as the guideline states) because progesterone's beneficial effect is complete by 12 weeks and the placenta assumes progesterone production thereafter. 7

Contraceptive Bleeding Management

• N92.1 – Excessive and frequent menstruation with irregular cycle (menometrorrhagia): This code may be used when progesterone is prescribed to manage heavy or prolonged bleeding in women using copper IUDs or levonorgestrel IUDs. 8
• For unscheduled spotting or heavy bleeding in IUD users, the CDC recommends NSAIDs for 5–7 days as first-line therapy; hormonal treatment with combined oral contraceptives or estrogen for 10–20 days is second-line. 8

Critical Documentation Requirements

• Always document the presence or absence of an intact uterus in the medical record when prescribing progesterone for hormone replacement therapy, as this determines medical necessity. 3, 4
• Exclude pregnancy before initiating progesterone for any indication other than threatened miscarriage or preterm birth prevention; the FDA label lists known or suspected pregnancy as a contraindication for progesterone capsules used in hormone replacement therapy. 4
• Document prior spontaneous preterm birth (gestational age and year) when prescribing 17-OHP-C, as insurance coverage requires evidence of the specific indication. 1, 2
• Record the date of last menstrual period when prescribing progesterone for secondary amenorrhea to establish the duration of amenorrhea (≥90 days is the FDA-studied threshold). 4

Common Pitfalls to Avoid

• Do not use diagnosis codes for contraception (Z30.x) when prescribing progesterone for hormone replacement therapy, as combined oral contraceptives containing ethinylestradiol are not appropriate for physiological hormone replacement in premature ovarian insufficiency or menopause. 5, 6
• Do not use codes for abnormal uterine bleeding (N93.x) when the primary indication is endometrial protection during estrogen therapy; use the menopausal code (N95.1) instead. 3
• Do not document "undiagnosed abnormal genital bleeding" (N93.9) when prescribing progesterone, as this is an FDA contraindication; bleeding must be evaluated and a specific diagnosis established before therapy. 4
• Do not use O47.x codes (false labor) when prescribing 17-OHP-C for preterm birth prevention; the correct code is O09.29x (supervision of pregnancy with history of preterm labor). 1, 2