Mirena Adverse Drug Reactions

Menstrual Bleeding Changes

Many women (approximately 64%) experience amenorrhea or infrequent bleeding over the first 2 years, which is generally considered a therapeutic benefit rather than a harmful effect 1
Approximately 15% report frequent or prolonged bleeding, particularly in the first 3-6 months 1
Unscheduled spotting or light bleeding is common, especially initially, and typically decreases with continued use 2, 3
The American Academy of Pediatrics recommends considering screening for STIs, particularly in adolescents, when unscheduled bleeding occurs 1, 2

There is a small risk of pelvic infection limited to the first 20-21 days after insertion 4, 5
The Centers for Disease Control and Prevention recommends awareness of this condition to avoid unnecessary surgical interventions 4

Efficacy may be impaired by hepatic enzyme-inducing drugs acting on the cytochrome P450 pathway 1, 2
The World Health Organization recommends caution with efavirenz (HIV medication), nevirapine, and most protease inhibitors 4
Contraceptive failures have been described in women receiving efavirenz-containing antiretroviral therapy 4

Current or recent (past 3 months) pelvic inflammatory disease is an absolute contraindication 4, 5
The American College of Obstetricians and Gynecologists recommends enhanced pre-insertion counseling about expected bleeding patterns to reduce discontinuation rates 1, 6