---
title: Does RU 486, a progesterone-blocking medication, help PMS? | Niyora
description: No, RU 486 did not reduce PMS symptoms compared to placebo, suggesting that blocking progesterone does not help PMS.
url: https://niyora.com/research/papers/persistence-of-premenstrual-syndrome-during-low-dose-administration-of-the-1994/
---

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- Does RU 486, a progesterone-blocking medication, help PMS?

Randomised trial, 1994

# Does RU 486, a progesterone-blocking medication, help PMS?

No, RU 486 did not reduce PMS symptoms compared to placebo, suggesting that blocking progesterone does not help PMS.

 Moderate study design

Seven women with severe PMS

## What they did

Seven women with severe PMS participated in a 6-month randomized, double-blind, placebo-controlled crossover study. They received either low-dose RU 486 (5 mg every other day for four doses) or placebo for 3 months each, starting 3 days after ovulation.

## What they found

PMS symptoms were similar during RU 486 treatment and placebo treatment. No significant reduction in physical or behavioral symptoms occurred with RU 486.

## What it means for you

Blocking the action of progesterone does not help PMS, which suggests progesterone itself may not be the primary cause of PMS. The study was very small and would need to be repeated in a larger group.

7

women with severe PMS

5 mg

RU 486 dose

6

months total study duration

## About the study

Original title Persistence of premenstrual syndrome during low-dose administration of the progesterone antagonist RU 486 Authors Chan AF, Mortola JF, Wood SH et al. Journal Obstetrics and gynecology Year 1994 Study design Randomised trial What was tested RU 486 5 mg every other day for four doses versus placebo Read the paper [https://pubmed.ncbi.nlm.nih.gov/7970453/](https://pubmed.ncbi.nlm.nih.gov/7970453/)

## Topics

[Premenstrual syndrome (PMS)](https://niyora.com/research/topics/condition-pms/)

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