--- title: Does fluoxetine change menstrual cycle length in women with premenstrual dysphoria? description: Yes, fluoxetine, especially at 60 mg per day, can change menstrual cycle length by 4 or more days, occurring in 15% of the 60 mg group versus 3% of the placeb url: https://niyora.com/research/papers/effect-of-fluoxetine-on-menstrual-cycle-length-in-women-with-premenstrual-1997/ --- - [Niyora](https://niyora.com/) - [Research](https://niyora.com/research/) - [Library](https://niyora.com/research/library/) - Does fluoxetine change menstrual cycle length in women with premenstrual dysphoria? Randomised trial, 1997 # Does fluoxetine change menstrual cycle length in women with premenstrual dysphoria? Yes, fluoxetine, especially at 60 mg per day, can change menstrual cycle length by 4 or more days, occurring in 15% of the 60 mg group versus 3% of the placebo group. Moderate study design 70 women with premenstrual dysphoria who didn't respond to placebo ## What they did A two-phase study: first a 2-cycle single-blind placebo phase, then a 6-cycle double-blind phase. Only women who didn't respond to placebo were randomized to placebo, fluoxetine 20 mg daily, or fluoxetine 60 mg daily. Cycle length was tracked daily using prospective calendars. ## What they found At the end of the first treatment cycle, 11 of 62 women on 60 mg fluoxetine and 7 of 70 women on 20 mg fluoxetine, but only 1 of 61 women on placebo, showed cycle-length change of 4 or more days (P = .011). Over two or three treatment cycles, 15% of the 60 mg group, 6% of the 20 mg group, and 3% of the placebo group showed cycle changes (P = .048). Changes were either cycle shortening or lengthening equally. ## What it means for you Fluoxetine can affect menstrual cycle length in some women, particularly at higher doses, which is important for women of reproductive age taking antidepressants. The study only included women who didn't respond to placebo first. 11 of 62 Women on 60 mg with cycle change by end of first cycle 15% Women on 60 mg with cycle change over multiple cycles 3% Women on placebo with cycle change ## About the study Original title Effect of fluoxetine on menstrual cycle length in women with premenstrual dysphoria Authors Steiner M, Lamont J, Steinberg S et al. Journal Obstetrics and gynecology Year 1997 Study design Randomised trial Participants 70 What was tested Fluoxetine 20 mg or 60 mg daily Read the paper [doi.org/10.1016/s0029-7844(97)00307-4](https://doi.org/10.1016/s0029-7844(97)00307-4) ## Topics [Premenstrual syndrome (PMS)](https://niyora.com/research/topics/condition-pms/)[Premenstrual dysphoric disorder (PMDD)](https://niyora.com/research/topics/condition-pmdd/)[Low mood and depression](https://niyora.com/research/topics/symptom-depression-mood/)[SSRIs and antidepressants](https://niyora.com/research/topics/treatment-ssri/) Research tells you what helps on average. Niyora helps on the day it hits. Calm down, see it another way, and decide what to say, with a PMS and PMDD app built by a doctor. ## Related studies Systematic review, 2024 What are the best treatments for PMDD and PMS? Review, 2024 What are the most effective treatments for PMDD? Systematic review, 2024 Do SSRI antidepressants help treat PMS and PMDD? Randomised trial, 2023 Does taking sertraline when PMDD symptoms start improve how well women function? Guideline, 2023 How are GnRH agonists used to treat PMDD that doesn't respond to standard medications? Review, 2022 What causes severe PMS and what treatments work? Ask AI about this page Copy prompt ChatGPT ↗ Claude ↗ Perplexity ↗ Google AI Mode ↗ Grok ↗