The normal thickness of the endometrium changes throughout a person?s life, from childhood, through to sexual maturity, fertile years, and after menopause.
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what to know about endometrial thickness
medically reviewed by valinda riggins nwadike, md, mph ? written by danielle dresden on november 19, 2019
normal thickness
measurement
causes of thin or thick lining
symptoms
treatments
seeing a doctor
outlook
the endometrium is the lining of the uterus. It is one of the few organs in the human body that changes in size every month throughout a person?s fertile years.
Each month, as part of the menstrual cycle, the body prepares the endometrium to host an embryo. Endometrial thickness increases and decreases during the process.
Two hormones, estrogen and progesterone, prompt these cycles of endometrial growth and its shedding through menstruation if a pregnancy does not develop.
In this article, we look at the normal range for endometrial thickness, causes of changes, and when to see a doctor.
Normal thickness
a healthcare provider may measure the thickness of the endometrium with an ultrasound.
The normal thickness of the endometrium changes throughout a person?s life, from childhood, through to sexual maturity, fertile years, and after menopause.
In imaging tests of young females who have not yet begun menstruating, the endometrium is present but smaller than it will be later in life.
According to the radiological society of north america (rsna), the endometrium is at its thinnest during menstruation, when it usually measures between 2?4 millimeters (mm) in thickness.
The first half of the proliferative phase starts around day 6 to 14 of a person?s cycle, or the time between the end of one menstrual cycle, when bleeding stops, and before ovulation. At this phase, the endometrium begins to thicken and may measure between 5?7 mm.
As the cycle progresses and moves towards ovulation, the endometrium grows thicker, up to about 11 mm.
About 14 days into a person?s cycle, hormones trigger the release of an egg. During this secretory phase, endometrial thickness is at its greatest and can reach 16 mm.
Pregnancy
endometrial thickness is important in pregnancy. Healthcare experts link the best chances for a healthy, full-term pregnancy to an endometrium that is neither too thin nor too thick. This allows the embryo to implant successfully and receive the nutrition it needs. The endometrium gets thicker as the pregnancy progresses.
Menopause
the rsna also state that in healthy postmenopausal people, the endometrium typically measures about 5 mm or less.
How to measure
ultrasound is the most common way to measure the thickness of the endometrium. It is the method that healthcare providers use first, especially if an individual has reported abnormal vaginal bleeding.
When ultrasound is not suitable, often due to the position of a person?s uterus or other health conditions, doctors use mri.
Causes of a very thin or thick endometrial lining
the thickness of the endometrium changes during a person?s menstrual cycle, but other factors can prompt changes as well.
One of the more common causes of changes in endometrial thickness is pregnancy. Women who are having an ectopic pregnancy or who are less than 5 weeks pregnant may show signs of a thickening endometrium.
Cancer of the endometrium or the ovaries is one of the most severe conditions that can lead to an increase in endometrial thickness. According to the american cancer societytrusted source, endometrial cancer is the most common cancer affecting a person?s reproductive systems. Developing more often in white people than african american people, endometrial cancer is rare in females under 45. The average age at diagnosis is 60.
Other factors contributing to a greater thickness of the endometrium include:
obesity
hormone replacement therapy (hrt)
tamoxifen
chronic high blood pressure
endometrial polyps
diabetes
scar tissue
endometrial hyperplasia.