---
title: How does prolactin change during a full day and night across the menstrual cycle?
description: Prolactin goes up and down in irregular episodes throughout day and night. The pattern of these ups and downs changes depending on time of day and whether som
url: https://niyora.com/research/papers/prolactin-concentrations-during-the-normal-menstrual-cycle-rhythms-within-1989/
---

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- How does prolactin change during a full day and night across the menstrual cycle?

Study, 1989

# How does prolactin change during a full day and night across the menstrual cycle?

Prolactin goes up and down in irregular episodes throughout day and night. The pattern of these ups and downs changes depending on time of day and whether someone is asleep or awake.

 Early or limited evidence

Women with normal menstrual cycles (specific number not stated)

## What they did

Blood samples were drawn frequently over 2-hour periods at different times during day and night in both the first and second halves of the menstrual cycle to measure prolactin.

## What they found

Prolactin showed irregular fluctuations throughout the 24-hour day. The pattern of these fluctuations varied depending on what time of day blood was drawn and whether the woman was sleeping or awake.

## What it means for you

How much prolactin is released and when it goes up and down depend on time of day and sleep state. This is a small study with limited information on the specific patterns observed.

2-hour periods

blood sampling duration

## About the study

Original title Prolactin concentrations during the normal menstrual cycle: rhythms within rhythms Authors Tennekoon KH, Lenton EA Journal The Ceylon medical journal Year 1989 Study design Study What was tested None (observation only) Read the paper [https://pubmed.ncbi.nlm.nih.gov/2620370/](https://pubmed.ncbi.nlm.nih.gov/2620370/)

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