Is it okay for a perimenopausal woman with an intact uterus who still experiences periods to take continuous progestin?

Continuous Progestin for Perimenopausal Women with Periods

No, you should not take continuous progestin alone if you still have periods and an intact uterus—this is dangerous and increases endometrial cancer risk. 1 If you need hormone therapy during perimenopause while still menstruating, you must pair progestin with estrogen in the correct regimen to protect your endometrium. 2

Why Progestin Alone Is Contraindicated

• Unopposed estrogen (which your body still produces during perimenopause) increases endometrial cancer risk in women with an intact uterus, and progestin alone does not address this if you're not taking estrogen replacement. 1
• The critical issue is that if you're still having periods, your ovaries are producing estrogen intermittently, and taking progestin alone creates an imbalanced hormonal environment without adequate endometrial protection. 3

The Correct Approach: Combined Estrogen-Progestin Therapy

If you need hormone therapy during perimenopause, you must use combined estrogen-progestin therapy, not progestin alone. 2 Here's the evidence-based regimen:

Recommended First-Line Regimen

• Oral micronized progesterone 200 mg daily for 12-14 days per 28-day cycle (sequential regimen) combined with transdermal 17β-estradiol 50-100 μg daily patches. 2
• This sequential approach induces predictable withdrawal bleeding and provides proven endometrial protection. 2
• Transdermal estradiol is strongly preferred over oral formulations because it has significantly lower cardiovascular and thrombotic risk—critical since stroke, venous thromboembolism, and coronary events occur within the first 1-2 years of hormone therapy. 2

Alternative Progestin Options (If Micronized Progesterone Unavailable)

• Medroxyprogesterone acetate 10 mg daily for 12-14 days per month is a widely available alternative, though it has less favorable metabolic effects on lipid profiles. 2, 4
• Norethindrone acetate 1 mg daily offers superior cardiovascular and metabolic outcomes compared to medroxyprogesterone acetate while maintaining excellent endometrial protection. 4
• Dydrogesterone 10 mg daily for 12-14 days per month is another alternative option. 2

Critical Dosing Principles You Cannot Ignore

• Never use progestin for fewer than 12 days per cycle in sequential regimens—this provides inadequate endometrial protection and increases cancer risk. 2
• The 12-14 day duration mimics the natural luteal phase and is the minimum required for endometrial safety. 2
• Continuous combined regimens (progestin given daily without interruption) are an alternative that results in amenorrhea rather than withdrawal bleeding, but these are typically reserved for postmenopausal women, not those still having periods. 2

Important Safety Considerations

Risks of Combined Estrogen-Progestin Therapy

• Per 10,000 women taking combined estrogen-progestin for 1 year, expect: 1
  • 8 additional invasive breast cancers
  • 7 additional coronary heart disease events
  • 8 more strokes
  • 8 more pulmonary emboli
  • 8 more deep venous thromboses
• These risks occur within the first 1-2 years of therapy, while breast cancer risk increases with longer-term use. 2

When Hormone Therapy Should NOT Be Used

• The USPSTF recommends against using hormone therapy for chronic disease prevention in postmenopausal women. 1, 5
• However, this recommendation specifically applies to postmenopausal women using HRT for disease prevention, not for managing perimenopausal symptoms. 1
• If you're taking this for symptom management (hot flashes, irregular bleeding), the risk-benefit calculation differs from chronic disease prevention. 1

Monitoring Requirements

• Annual clinical review focusing on compliance, bleeding patterns, and symptom control is mandatory. 2
• No routine laboratory monitoring is required unless specific symptoms arise. 2
• Use the lowest effective dose for the shortest duration consistent with your treatment goals. 2

Common Pitfall to Avoid

The most dangerous mistake is taking progestin alone without estrogen while still perimenopausal with an intact uterus. 4 This creates hormonal imbalance without addressing the underlying estrogen fluctuations of perimenopause and provides no endometrial protection against your body's own estrogen production. If you need progestin therapy, it must be properly paired with estrogen in evidence-based doses and durations. 2