Heavy bleeding and endometriosis

Combined oral contraceptive pills are first-line medical therapy for endo-associated pain, endorsed by all 8 major international guidelines. A 2025 network meta-analysis found COCPs significantly reduce pelvic pain versus placebo, though progestins (especially dienogest) may edge them out. Continuous dosing is better than cyclic for dysmenorrhoea and endometrioma recurrence. Key safety considerations: a 2025 Danish cohort of 2 million women found COCPs double the risk of stroke and MI versus no use (though absolute risk remains low), and 44% of endo patients discontinue due to mood-related side effects. Newer estradiol- and estetrol-based COCPs may have better safety profiles.

Dienogest is a daily 2 mg progestin tablet developed specifically for endometriosis and licensed for that purpose across Europe, Japan, much of Asia, Latin America, and (since 2024) Australia. The evidence base for pain reduction is among the strongest of any endometriosis treatment, but a meaningful minority of people stop because of mood changes, irregular bleeding, or other progestin side effects.

The levonorgestrel IUS (Mirena) is one of the most-studied hormonal treatments for endo, particularly effective for patients who also have adenomyosis. A 2022 meta-analysis of 71 RCTs found strong pain reduction in adenomyosis; for endo specifically it's comparable to oral progestins or COCPs but with dramatically better real-world adherence — 91.5% of users continued treatment beyond 5 years versus 21.9% on oral options. Two recent safety signals warrant informed discussion: a 2025 Korean cohort (n=61,010) found a 38% increased breast cancer risk, and a 2024 Danish cohort (n=149,200) found a dose-dependent increased depression risk. A 2025 study found no increased kidney disease risk.

Naproxen is widely recommended as first-line medication for endo-associated pain by ACOG, NICE, ESHRE and others, with strong evidence for menstrual pain generally but surprisingly thin endo-specific evidence. The 2015 Cochrane review of 80 RCTs confirmed NSAIDs significantly outperform placebo for primary dysmenorrhoea. For endo specifically, the 2017 Cochrane review found only one small RCT (Kauppila 1985) and concluded evidence was insufficient — not because NSAIDs don't work, but because they've never been properly tested in endo. Naproxen has mid-range GI risk among NSAIDs (higher than ibuprofen, lower than ketorolac). Take with food, ideally before period onset, and consider adding a PPI for regular use.