Guselkumab and Menstrual Bleeding
Guselkumab does not cause menstrual bleeding abnormalities and has no documented effect on menstrual cycles. This IL-23 inhibitor biologic has been extensively studied in large populations without any reported association with abnormal uterine bleeding or menstrual disturbances.
Evidence Base
The safety profile of guselkumab has been thoroughly evaluated across multiple large-scale studies:
No menstrual bleeding events reported: In an integrated analysis of 11 phase II/III clinical trials involving 4,399 guselkumab-treated patients followed for 10,787 patient-years, there were no adverse events related to menstrual bleeding or abnormal uterine bleeding documented 1
Comprehensive safety monitoring: The pooled safety data included patients across diverse demographics (52% female in some cohorts) and extended follow-up periods of up to 5 years in psoriasis studies, with no signals for menstrual-related adverse events 1
Real-world confirmation: Multiple real-world effectiveness studies spanning 52-104 weeks have consistently shown excellent safety profiles without reporting menstrual bleeding complications 2, 3
Mechanism Supports Safety Profile
Guselkumab's mechanism of action provides biological plausibility for the absence of menstrual effects:
Selective IL-23 inhibition: As a fully human IgG1 lambda monoclonal antibody that selectively binds the p19 subunit of IL-23, guselkumab does not interfere with coagulation pathways or hormonal regulation 4
No anticoagulant properties: Unlike direct oral anticoagulants (which are documented to cause abnormal uterine bleeding in 27-32% of women of reproductive age), guselkumab has no anticoagulant mechanism 5
Clinical Monitoring Recommendations
Standard monitoring for guselkumab does not require menstrual-specific assessments:
Baseline screening: Complete blood count, complete metabolic profile, tuberculosis testing, and hepatitis screening are recommended, but no menstrual history or gynecologic evaluation is required 5
Ongoing monitoring: Periodic history and physical examination with screening for infections and adverse effects, without specific attention to menstrual patterns 5
Important Caveat for Women of Childbearing Potential
While guselkumab does not affect menstrual bleeding, pregnancy considerations remain critical:
Unknown pregnancy safety: The safety of IL-23 inhibitors during pregnancy is unknown, and antibodies are effectively secreted during lactation 5
Contraception counseling: Women of childbearing potential should receive documented counseling and use appropriate contraception, though this relates to teratogenic concerns rather than menstrual effects 5