Basal hormone levels in women who use acetaminophen for menstrual pain

ObjectiveTo compare basal gonadotropin and estradiol levels between women using acetaminophen versus those using no or other types of analgesics.DesignObservational study.SettingThree IVF clinics in greater Boston.Patient(s)Three hundred eighty-six women accepted for their first IVF treatment who completed questionnaires recording medical history, including analgesic use for menstrual pain, and who had blood drawn during the menstrual phase of a cycle before treatment.Main outcome measure(s)Basal FSH, LH, and estradiol.Result(s)Basal hormone levels, especially LH, were lower for women who regularly used acetaminophen compared with women who used no medication or other types of analgesics. Lower hormone levels in acetaminophen users were consistently observed when women were subdivided by age, body mass index, smoking history, and degree of menstrual pain-features that might have influenced analgesic use or hormone levels.Conclusion(s)This study provides preliminary evidence that acetaminophen may lower gonadotropin and estradiol levels and offers a biologic basis for the epidemiologic observation that acetaminophen use may reduce the risk of ovarian cancer.