292 lines
No EOL
31 KiB
HTML
292 lines
No EOL
31 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en" id="article" class="nojs us" data-root="//medlineplus.gov" itemid="https://medlineplus.gov/ency/article/001218.htm" itemtype="http://schema.org/MedicalWebPage" itemscope="">
|
||
<head>
|
||
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/>
|
||
<meta http-equiv="window-target" content="_top"/>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
|
||
<meta charset="utf-8"/>
|
||
<meta property="fb:app_id" content="1042245625821448"/>
|
||
<meta name="expires" content="Wed, 05 02 2025"/>
|
||
<meta name="ac-dictionary" content="medlineplus-ac-dictionary"/>
|
||
<link rel="shortcut icon" href="https://medlineplus.gov/images/favicon.ico" type="image/x-icon"/>
|
||
<link rel="apple-touch-icon" href="//medlineplus.gov/images/touch-icon.png"/>
|
||
<meta name="viewport" content="width=device-width, initial-scale=1"/>
|
||
<link rel="stylesheet" href="https://medlineplus.gov/css/common_new.css?04272023"/>
|
||
<!--[if IE 8]> <link rel="stylesheet" href="https://medlineplus.gov/css/ie8/common.css"><![endif]-->
|
||
<link rel="stylesheet" href="https://medlineplus.gov/uswds/css/uswds_styles.css"/>
|
||
<link rel="stylesheet" href="https://medlineplus.gov/css/ency/ency2.css?07162024"/>
|
||
<script type="text/javascript">document.querySelector("html").className = document.querySelector("html").className.replace(/nojs[\s]*/g, '');</script>
|
||
<script src="https://medlineplus.gov/uswds/js/uswds-init.min.js" type="text/javascript">
|
||
</script>
|
||
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-MMVM77');</script>
|
||
<link rel="canonical" href="https://medlineplus.gov/ency/article/001218.htm" itemprop="url"/>
|
||
<link rel="alternative" hreflang="es" href="https://medlineplus.gov/spanish/ency/article/001218.htm"/>
|
||
<link rel="alternative" hreflang="en" href="https://medlineplus.gov/ency/article/001218.htm"/><meta property="og:title" content="Absent menstrual periods - primary: MedlinePlus Medical Encyclopedia"/><meta property="og:url" content="https://medlineplus.gov/ency/article/001218.htm"/><meta property="twitter:title" content="Absent menstrual periods - primary: MedlinePlus Medical Encyclopedia"/><meta name="twitter:card" content="summary_large_image"/><meta name="description" content="Absence of a woman's monthly menstrual period is called amenorrhea."/><meta itemprop="description" name="description" content="Absence of a woman's monthly menstrual period is called amenorrhea."/><meta property="og:description" content="Absence of a woman's monthly menstrual period is called amenorrhea."/><meta property="twitter:description" content="Absence of a woman's monthly menstrual period is called amenorrhea."/><meta property="og:image" content="https://medlineplus.gov/images/share_ency_1.jpg"/><meta property="og:image" content="https://medlineplus.gov/images/share_ency_2.jpg"/><meta property="og:image" content="https://medlineplus.gov/images/share_ency_3.jpg"/><meta property="twitter:image" content="https://medlineplus.gov/images/share_ency_1.jpg"/>
|
||
<title>Absent menstrual periods - primary: MedlinePlus Medical Encyclopedia</title>
|
||
</head>
|
||
<body><link href="http://schema.org/Patient" itemprop="audience"/>
|
||
<!-- Google Tag Manager -->
|
||
<noscript><iframe title="googletagmanager" src="//www.googletagmanager.com/ns.html?id=GTM-MMVM77" height="0" width="0" style="display:none;visibility:hidden">
|
||
</iframe>
|
||
</noscript>
|
||
<!-- End Google Tag Manager -->
|
||
<a name="top" id="top">
|
||
</a>
|
||
<a class="hide-offscreen" href="#start">Skip navigation</a>
|
||
<section class="usa-banner" aria-label="Official website of the United States government">
|
||
<div class="usa-accordion">
|
||
<header class="usa-banner__header">
|
||
<div class="usa-banner__inner">
|
||
<div class="grid-col-auto">
|
||
<img aria-hidden="true" class="usa-banner__header-flag" src="https://medlineplus.gov/uswds/img/us_flag_small.png" alt=""/>
|
||
</div>
|
||
<div class="grid-col-fill tablet:grid-col-auto" aria-hidden="true">
|
||
<p class="usa-banner__header-text">
|
||
An official website of the United States government
|
||
</p>
|
||
<p class="usa-banner__header-action">Here’s how you know</p>
|
||
</div>
|
||
<button type="button" class="usa-accordion__button usa-banner__button" aria-expanded="false" aria-controls="gov-banner-default-default">
|
||
<span class="usa-banner__button-text">Here’s how you know</span>
|
||
</button>
|
||
</div>
|
||
</header>
|
||
<div class="usa-banner__content usa-accordion__content" id="gov-banner-default-default">
|
||
<div class="grid-row grid-gap-lg">
|
||
<div class="usa-banner__guidance tablet:grid-col-6">
|
||
<img class="usa-banner__icon usa-media-block__img" src="https://medlineplus.gov/uswds/img/icon-dot-gov.svg" role="img" alt="" aria-hidden="true"/>
|
||
<div class="usa-media-block__body">
|
||
<p>
|
||
<strong>Official websites use .gov</strong><br/>A
|
||
<strong>.gov</strong> website belongs to an official government
|
||
organization in the United States.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<div class="usa-banner__guidance tablet:grid-col-6">
|
||
<img class="usa-banner__icon usa-media-block__img" src="https://medlineplus.gov/uswds/img/icon-https.svg" role="img" alt="" aria-hidden="true"/>
|
||
<div class="usa-media-block__body">
|
||
<p>
|
||
<strong>Secure .gov websites use HTTPS</strong><br/>A
|
||
<strong>lock</strong> (
|
||
<span class="icon-lock"><svg xmlns="http://www.w3.org/2000/svg" width="52" height="64" viewBox="0 0 52 64" class="usa-banner__lock-image" role="img" aria-labelledby="banner-lock-description-default" focusable="false">
|
||
<title id="banner-lock-title-default">Lock</title>
|
||
<desc id="banner-lock-description-default">Locked padlock icon</desc>
|
||
<path fill="#000000" fill-rule="evenodd" d="M26 0c10.493 0 19 8.507 19 19v9h3a4 4 0 0 1 4 4v28a4 4 0 0 1-4 4H4a4 4 0 0 1-4-4V32a4 4 0 0 1 4-4h3v-9C7 8.507 15.507 0 26 0zm0 8c-5.979 0-10.843 4.77-10.996 10.712L15 19v9h22v-9c0-6.075-4.925-11-11-11z">
|
||
</path>
|
||
</svg> </span>) or <strong>https://</strong> means you’ve safely connected to
|
||
the .gov website. Share sensitive information only on official,
|
||
secure websites.
|
||
</p>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</section>
|
||
<div id="mplus-wrap">
|
||
<header>
|
||
<div id="mplus-header">
|
||
<!-- Orgs
|
||
================================================== -->
|
||
<div id="mplus-orgs">
|
||
<a title="National Institutes of Health" target="_blank" class="nih-org" href="//www.nih.gov/">
|
||
<img alt="National Institutes of Health" src="https://medlineplus.gov/images/nihlogo.png" class="nihlogo"/>
|
||
</a><a target="_blank" href="https://www.nlm.nih.gov/"> National Library of Medicine </a>
|
||
</div>
|
||
<!-- Logo
|
||
================================================== -->
|
||
<div id="mplus-logo" class="years-25">
|
||
<a href="https://medlineplus.gov">
|
||
<img src="https://medlineplus.gov/images/m_logo_25.png" title="MedlinePlus Trusted Health Information for You" alt="MedlinePlus Trusted Health Information for You"/>
|
||
</a>
|
||
</div>
|
||
<!-- Nav Menu
|
||
================================================== -->
|
||
<div id="mplus-nav">
|
||
<div class="sm-live-area hide-offscreen" aria-live="polite">The navigation menu has been collapsed.</div>
|
||
<!-- Menu Button-->
|
||
<button type="submit" aria-controls="mplus-menu-list" role="button" title="Menu" class="navmenu-btn" id="sm-menu-btn" aria-pressed="false" tabindex="0">Menu<span class="icon icon-nav-menu">
|
||
</span></button><ul class="nav-list" id="mplus-menu-list">
|
||
<li><a href="https://medlineplus.gov/healthtopics.html">Health Topics</a></li>
|
||
<li><a href="https://medlineplus.gov/druginformation.html">Drugs & Supplements</a></li>
|
||
<li><a href="https://medlineplus.gov/genetics/">Genetics</a></li>
|
||
<li><a href="https://medlineplus.gov/lab-tests/">Medical Tests</a></li>
|
||
<li><a href="https://medlineplus.gov/encyclopedia.html">Medical Encyclopedia</a></li>
|
||
<li><a href="https://medlineplus.gov/about/">About MedlinePlus</a></li>
|
||
</ul><button type="submit" aria-controls="mplus-search" role="button" title="Search" class="navmenu-btn" id="sm-search-btn" aria-pressed="false" tabindex="0"><span class="hide-offscreen">Show </span>Search<span class="icon icon-nav-search">
|
||
</span></button>
|
||
<div class="top-1">
|
||
<!-- Search
|
||
================================================== -->
|
||
<form target="_self" title="Search MedlinePlus" action="//vsearch.nlm.nih.gov/vivisimo/cgi-bin/query-meta" method="get" id="mplus-search">
|
||
<input type="hidden" value="medlineplus" name="v:project"/>
|
||
<input type="hidden" value="medlineplus-bundle" name="v:sources"/>
|
||
<div class="form-box text-combo">
|
||
<div class="form-area"><label for="searchtext_primary" class="hide-offscreen">Search MedlinePlus</label>
|
||
<span role="status" aria-live="polite" class="ui-helper-hidden-accessible">
|
||
</span><input type="text" aria-haspopup="true" aria-autocomplete="list" role="textbox" autocomplete="off" name="query" size="40" maxlength="400" title="Site Search input" alt="Site Search input" placeholder="Search MedlinePlus" class="form-text ui-autocomplete-input" id="searchtext_primary"/>
|
||
</div>
|
||
<div class="button-area">
|
||
<button type="submit" alt="Search MedlinePlus" title="Search MedlinePlus" class="form-btn">GO</button>
|
||
</div>
|
||
</div>
|
||
</form>
|
||
<!-- Secondary Nav
|
||
================================================== -->
|
||
<div class="secondarynav">
|
||
<ul class="nav-list">
|
||
<li><a href="https://medlineplus.gov/about/"><span>About MedlinePlus</span></a></li>
|
||
<li><a href="https://medlineplus.gov/whatsnew/"><span>What's New</span></a></li>
|
||
<li><a href="https://medlineplus.gov/sitemap.html"><span>Site Map</span></a></li>
|
||
<li><a target="_blank" href="https://support.nlm.nih.gov/knowledgebase/category/?id=CAT-01231&category=medlineplus&from=//medlineplus.gov/ency/article/001218.htm"><span>Customer Support</span></a></li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
<!-- Nav Bar
|
||
================================================== -->
|
||
<div id="mplus-nav-bar">
|
||
<ul class="nav-list">
|
||
<li><a href="https://medlineplus.gov/healthtopics.html">Health Topics</a></li><li><a href="https://medlineplus.gov/druginformation.html">Drugs & Supplements</a></li><li><a href="https://medlineplus.gov/genetics/">Genetics</a></li><li><a href="https://medlineplus.gov/lab-tests/">Medical Tests</a></li><li><a href="https://medlineplus.gov/encyclopedia.html">Medical Encyclopedia</a></li>
|
||
</ul>
|
||
</div>
|
||
<a title="Español" id="mplus-lang-toggle" href="../../spanish/ency/article/001218.htm">Español</a>
|
||
</div>
|
||
</div>
|
||
</header>
|
||
<!-- Content
|
||
================================================== -->
|
||
<div id="mplus-content">
|
||
<!-- Breadrcumbs -->
|
||
<div id="breadcrumbs"><div itemtype="http://schema.org/BreadcrumbList" itemscope="" itemprop="breadcrumb"><span class="hide-offscreen">You Are Here:</span>
|
||
<div itemscope itemprop="itemListElement" itemtype="http://schema.org/ListItem">
|
||
<a href="https://medlineplus.gov" itemprop="item"><span itemprop="name">Home</span></a>
|
||
→
|
||
<meta itemprop="position" content="1"/>
|
||
</div>
|
||
|
||
<div itemscope itemprop="itemListElement" itemtype="http://schema.org/ListItem">
|
||
<a href="https://medlineplus.gov/encyclopedia.html" itemprop="item"><span itemprop="name">Medical Encyclopedia</span></a>
|
||
→
|
||
<meta itemprop="position" content="2"/>
|
||
</div>
|
||
</div><div><span>Absent menstrual periods - primary</span></div></div>
|
||
<span class="page-url print-only">URL of this page: //medlineplus.gov/ency/article/001218.htm
|
||
</span>
|
||
<!-- Article -->
|
||
<article><div id="d-article"><div class="page-info"><div class="page-title"><a name="start" id="start">
|
||
</a><h1 class="with-also" itemprop="name">Absent menstrual periods - primary</h1>
|
||
</div><div class="page-actions">
|
||
</div>
|
||
<noscript>
|
||
<span class="js-disabled-message">To use the sharing features on this page, please enable JavaScript.</span>
|
||
</noscript></div><div class="main"><div id="ency_summary"><p>Absence of a woman's monthly menstrual period is called amenorrhea.</p><p>Primary amenorrhea is when a girl has not yet started her monthly periods, and she:</p><ul><li>Has gone through other normal changes that occur during puberty</li><li>Is older than 15</li></ul></div><section><div class="section"><div class="section-header"><div class="section-title"><h2>Causes</h2></div><div class="section-button"><button type="submit" aria-controls="section-1" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-1"><p>Most girls begin their periods between ages 9 and 18. The average is around 12 years old. If no periods have occurred when a girl is older than 15, further testing may be needed. The need is more urgent if she has gone through other normal changes that occur during puberty.</p><p>Being born with incompletely formed genital or pelvic organs can lead to a lack of menstrual periods. Some of these defects include:</p><ul><li>Blockages or narrowing of the cervix</li><li><a test="test" href="./001497.htm">Hymen</a> that has no opening</li><li>Missing uterus or vagina</li><li>Vaginal septum (a wall that divides the vagina into 2 sections)</li></ul><p>Hormones play a big role in a woman's menstrual cycle. Hormone problems can occur when:</p><ul><li>Changes occur to the parts of the brain where hormones that help manage the menstrual cycle are produced.</li><li>The ovaries are not working correctly.</li></ul><p>Either of these problems may be due to:</p><ul><li><a test="test" href="./000362.htm">Anorexia</a> (loss of appetite) with low body mass index (BMI)</li><li>Chronic or long-term illnesses, such as <a test="test" href="./000107.htm">cystic fibrosis</a> or heart disease</li><li>Genetic defects or disorders</li><li>Infections that occurred before or after the woman's birth</li><li>Other birth defects</li><li>Poor nutrition</li><li>Tumors </li></ul><p>In many cases, the cause of primary amenorrhea is not known.</p></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>Symptoms</h2></div><div class="section-button"><button type="submit" aria-controls="section-2" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-2"><p>A female with amenorrhea will have no menstrual flow. She may have other signs of puberty.</p></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>Exams and Tests</h2></div><div class="section-button"><button type="submit" aria-controls="section-3" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-3"><p>The health care provider will perform a physical exam to check for birth defects of the vagina or uterus.</p><p>The provider will ask questions about:</p><ul><li>Your medical history</li><li>Medicines and supplements you may be taking</li><li>How much exercise you do</li><li>Your eating habits </li></ul><p>A pregnancy test will be done.</p><p>Blood tests to measure different hormone levels may include:</p><ul><li><a test="test" href="./003711.htm">Estradiol</a></li><li><a test="test" href="./003710.htm">Follicle stimulating hormone</a> (FSH)</li><li><a test="test" href="./003708.htm">Luteinizing hormone</a> (LH)</li><li><a test="test" href="./003718.htm">Prolactin</a></li><li><a test="test" href="./003713.htm">17 hydroxyprogesterone</a></li><li><a test="test" href="./003714.htm">Serum progesterone</a></li><li>Serum testosterone level</li><li><a test="test" href="./003684.htm">Thyroid stimulating hormone</a> (TSH)</li><li><a test="test" href="./003687.htm">T3</a> and <a test="test" href="./003517.htm">T4</a></li></ul><p>Other tests that may be done include:</p><ul><li><a test="test" href="./003935.htm">Chromosome or genetic testing</a></li><li><a test="test" href="./003786.htm">Head CT scan</a> or <a test="test" href="./003791.htm">head MRI scan</a> to look for brain tumors</li><li>Pelvic ultrasound or MRI to look for birth defects </li></ul></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>Treatment</h2></div><div class="section-button"><button type="submit" aria-controls="section-4" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-4"><p>Treatment depends on the cause of the missing period. Lack of periods that is caused by birth defects may require hormone medicines, surgery, or both.</p><p>If the amenorrhea is caused by a tumor in the brain:</p><ul><li>Medicines may shrink certain types of tumors.</li><li>Surgery to remove the tumor may also be needed.</li><li><a test="test" href="./001918.htm">Radiation therapy</a> is usually only done when other treatments have not worked. </li></ul><p>If the problem is caused by a systemic disease, treatment of the disease may allow menstruation to begin.</p><p>If the cause is <a test="test" href="./000341.htm">bulimia</a>, anorexia or too much exercise, periods will often begin when the weight returns to normal or the exercise level is decreased.</p><p>If the amenorrhea cannot be corrected, hormone medicines can sometimes be used. Medicines can help the woman feel more like her friends and female family members. They can also protect the bones from becoming too thin (<a test="test" href="./000360.htm">osteoporosis</a>).</p></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>Outlook (Prognosis)</h2></div><div class="section-button"><button type="submit" aria-controls="section-5" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-5"><p>The outlook depends on the cause of the amenorrhea and whether it can be corrected with treatment or lifestyle changes. </p><p>Periods are not likely to start on their own if the amenorrhea was caused by one of the following conditions:</p><ul><li>Birth defects of the female organs</li><li><a test="test" href="./000345.htm">Craniopharyngioma</a> (a tumor near the pituitary gland at the base of the brain)</li><li>Cystic fibrosis</li><li>Genetic disorders </li></ul><p>You may have emotional distress because you feel different from friends or family. Or, you may worry that you might not be able to have children.</p></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>When to Contact a Medical Professional</h2></div><div class="section-button"><button type="submit" aria-controls="section-6" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-6"><p>Contact your provider if your daughter is older than 15 and has not yet begun menstruating, or if she is 14 or older and shows no other signs of puberty.</p></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>Alternative Names</h2></div><div class="section-button"><button type="submit" aria-controls="section-Alt" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-Alt"><p>Primary amenorrhea; No periods - primary; Absent periods - primary; Absent menses - primary; Absence of periods - primary</p></div></div></section><section><div class="section sec-mb"><div class="section-header"><div class="section-title"><h2>Images</h2></div><div class="section-button"><button type="submit" aria-controls="section-tnails" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div name="Images" class="section-body" id="section-tnails"><ul class="img-grid group">
|
||
<li><img src="//medlineplus.gov/ency/images/ency/tnails/17125t.jpg" alt="Primary amenorrhea" title="Primary amenorrhea" class="side-img"/><a href="../imagepages/17125.htm">Primary amenorrhea</a></li>
|
||
<li><img src="//medlineplus.gov/ency/images/ency/tnails/8608t.jpg" alt="Normal uterine anatomy (cut section)" title="Normal uterine anatomy (cut section)" class="side-img"/><a href="../imagepages/8608.htm">Normal uterine anatomy (cut section)</a></li>
|
||
<li><img src="//medlineplus.gov/ency/images/ency/tnails/17088t.jpg" alt="Absence of menstruation (amenorrhea)" title="Absence of menstruation (amenorrhea)" class="side-img"/><a href="../imagepages/17088.htm">Absence of menstruation (amenorrhea)</a></li>
|
||
</ul></div></div></section><section><div class="section"><div class="section-header"><div class="section-title"><h2>References</h2></div><div class="section-button"><button type="submit" aria-controls="section-Ref" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div class="section-body" id="section-Ref"><p>Bulun SE. Physiology and pathology of the female reproductive axis. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. <em>Williams Textbook of Endocrinology</em>. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 17.</p><p>Cameron S. Menstruation and amenorrhoea. In: Magowan B, ed. <em>Clinical Obstetrics and Gynaecology</em>. 5th ed. Elsevier; 2023:chap 4.</p><p>Lobo RA. Primary and secondary amenorrhea and precocious puberty: etiology, diagnostic evaluation, management. In: Gershenson DM, Lentz GM, Valea FA, Lobo RA, eds. <em>Comprehensive Gynecology</em>. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 36.</p></div></div></section>
|
||
<section><div class="section"><div class="section-header"><div class="section-title"><h2>Review Date 4/16/2024</h2></div><div class="section-button"><button type="submit" aria-controls="section-version" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div>
|
||
<div id="section-version" class="section-body"><p>Updated by: John D. Jacobson, MD, Professor Emeritus, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. </p>
|
||
</div></div></section><section><div class="section ency-citation"><div class="section-header"><div class="section-title ency-citation"><div id="citation-how-to"><button><span>Learn how to cite this page</span></button></div></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div></div></section><section><div class="section sec-mb"><div class="section-header"><div class="section-title"><h2>Related MedlinePlus Health Topics</h2></div><div class="section-button"><button type="submit" aria-controls="section-mtp" role="button" title="Expand/Collapse section"><span class="icon icon-section-action">
|
||
</span></button></div><div class="sm-live-area hide-offscreen" aria-live="polite">
|
||
</div></div><div name="Related MedlinePlus Health Topics" class="section-body" id="section-mtp"><ul class="side-nav"><li><a href="https://medlineplus.gov/menstruation.html">Menstruation</a></li>
|
||
|
||
|
||
</ul></div></div></section></div></div></article>
|
||
</div>
|
||
<footer>
|
||
|
||
<div class="provider-box group">
|
||
<div class="urac-logo">
|
||
<a href="https://accreditnet.urac.org/directory/#/certification/HCP-2/info"><img src="https://medlineplus.gov/images/CertifiedSeal.png"/></a>
|
||
<p class="urac-logo-info">Health Content Provider<br>06/01/2025</p>
|
||
</div>
|
||
<p class="adam-info">
|
||
<a href='javascript:urac_open();'>A.D.A.M., Inc. is accredited by URAC</a>, for Health Content Provider (www.urac.org). URAC's <a href='javascript:hwsopen();'>accreditation program</a> is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s <a href='javascript:edpolopen();'>editorial policy, editorial process</a>, and <a href='javascript:ppopen();'>privacy policy</a>. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: <a href='javascript:honc_open();'>verify here</a>.
|
||
</p>
|
||
</div>
|
||
<p class="adam-info">
|
||
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only – they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997-2025 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
|
||
</p>
|
||
<div class="adam-logo">
|
||
<a href="https://www.adam.com/about" target="_blank"><img width="49" height="10" alt="About A.D.A.M." src="https://medlineplus.gov/ency/images/ency/ftrAdamlogo.gif"/></a>
|
||
</div>
|
||
<div id="mplus-footer">
|
||
<div class="footer1">
|
||
<ul class="secondarynav">
|
||
<li><a href="https://medlineplus.gov/about/">About MedlinePlus</a></li>
|
||
<li><a href="https://medlineplus.gov/whatsnew/">What's New</a></li>
|
||
<li><a href="https://medlineplus.gov/sitemap.html">Site Map</a></li>
|
||
<li><a name="contact" target="_blank" href="https://support.nlm.nih.gov/knowledgebase/category/?id=CAT-01231&category=medlineplus&from="><span>Customer Support</span></a></li>
|
||
</ul>
|
||
<ul class="follow-footer">
|
||
<li><a href="https://medlineplus.gov/rss.html" class="follow-item">Subscribe to RSS<img src="https://medlineplus.gov/images/feed.png" class="social-media-toolkit-icon" alt="RSS" title="RSS"></a></li>
|
||
<li><span class="follow-label">Follow us</span>
|
||
<a href="https://twitter.com/medlineplus" class="follow-item" target="_blank"><img src="https://medlineplus.gov/images/i_share_twitter.png" class="follow-icon" alt="X" title="X"></a>
|
||
<a href="https://facebook.com/Mplus.gov/" class="follow-item" target="_blank"><img src="https://medlineplus.gov/images/i_share_fb.png" class="follow-icon" alt="Facebook" title="Facebook"></a>
|
||
<a href="https://www.instagram.com/mplusgov/" class="follow-item" target="_blank"><img src="https://medlineplus.gov/images/Instagram_Glyph_Gradient_RGB.png" class="follow-icon" alt="Instagram" title="Instagram"></a>
|
||
</li>
|
||
<li><a href="https://medlineplus.gov/social-media-toolkit/" class="social-media-toolkit-item">Social Media Toolkit<img src="https://medlineplus.gov/images/i_social_media_toolkit.png" class="social-media-toolkit-icon" alt="Social Media Toolkit" title="Social Media Toolkit"></a></li>
|
||
</ul>
|
||
</div>
|
||
<div class="footer2">
|
||
<ul>
|
||
<li><a href="https://www.nlm.nih.gov/web_policies.html" target="_blank">NLM Web Policies</a></li>
|
||
<li><a href="https://medlineplus.gov/about/using/usingcontent/" >Copyright</a></li>
|
||
<li><a href="//medlineplus.gov/accessibility.html">Accessibility</a></li>
|
||
<li><a href="https://medlineplus.gov/about/using/criteria/">Guidelines for Links</a></li>
|
||
<li><a href="//medlineplus.gov/plugins.html">Viewers & Players</a></li>
|
||
<li><a href="https://www.hhs.gov/vulnerability-disclosure-policy/index.html" target="_blank">HHS Vulnerability Disclosure</a></li>
|
||
<li><a href="https://medlineplus.gov/medlineplus-connect/">MedlinePlus Connect for EHRs</a></li>
|
||
<li><a href="https://medlineplus.gov/about/developers/">For Developers</a></li>
|
||
</ul>
|
||
<div class="address">
|
||
<a href="//www.nlm.nih.gov" target="_blank">National Library of Medicine</a>
|
||
<span>8600 Rockville Pike, Bethesda, MD 20894</span>
|
||
<a href="//www.hhs.gov" target="_blank">U.S. Department of Health and Human Services</a>
|
||
<a href="//www.nih.gov" target="_blank">National Institutes of Health</a>
|
||
</div>
|
||
<div class="return-top"><a href="#top" title="Return to top"><img class="return-top-icon" alt="Return to top" src="https://medlineplus.gov/images/return-top.png"></a></div>
|
||
</div>
|
||
</div>
|
||
|
||
</footer>
|
||
</div><!-- End Wrap -->
|
||
<script src="https://medlineplus.gov/jslib/jquery-3.6.0.min.js" type="text/javascript">
|
||
</script>
|
||
<script src="https://medlineplus.gov/jslib/mplus-frontend-controls.js" type="text/javascript">
|
||
</script>
|
||
<!--[if lte IE 9]>
|
||
<script src="https://medlineplus.gov/jslib/jquery.placeholder.js" type="text/javascript"></script>
|
||
<![endif]-->
|
||
<script src="https://medlineplus.gov/jslib/mplus-share.js?id=1112022" type="text/javascript">
|
||
</script>
|
||
<script src="https://medlineplus.gov/jslib/control.js" type="text/javascript">
|
||
</script>
|
||
<script src="https://medlineplus.gov/uswds/js/uswds.min.js" type="text/javascript">
|
||
</script>
|
||
<script src="https://medlineplus.gov/jslib/ency/ency.js" type="text/javascript">
|
||
</script>
|
||
</body>
|
||
</html> |