The endometrium is the tissue lining the inside of the uterus and plays a crucial role in the reproductive process. It is a key component of women’s reproductive health and can significantly influence fertility and menstrual disorders. Any concerns should be discussed with a physician to receive proper evaluation and care.

Functions of the Endometrium

The endometrium prepares each month for the implantation of a fertilized egg. If fertilization does not occur, it is shed as menstruation. If pregnancy begins, it becomes the site where the embryo implants and develops. Its main functions include

Preparation for implantation: The endometrium thickens each menstrual cycle to create an optimal environment for implantation.
Nutrition and support: It provides essential nutrients to the embryo in the early stages of development.
Menstrual cycle: In the absence of pregnancy, the functional layer of the endometrium is shed during menstruation.
Maintaining pregnancy: After implantation, the endometrium becomes the decidua, supporting the embryo until the placenta takes over.

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Variations in Thickness

Under the influence of estrogen and progesterone, the endometrium changes thickness throughout the menstrual cycle. It is considered receptive to pregnancy when it measures at least 7 mm and has a trilaminar appearance.

Menstrual cycle phases:

• Follicular phase: The endometrium is thin and gradually thickens under estrogen.
• Luteal phase: Progesterone causes significant thickening, preparing for possible implantation.

Other factors affecting thickness:

• Irregular cycles: May cause the endometrium to be too thin or too thick.
• Menopause: Thickness decreases considerably due to reduced hormone levels.
• Pregnancy: The endometrium remains thick to support embryonic development.
• Pathologies: Conditions such as endometrial hyperplasia or fibroids may cause abnormal thickening.

Monitoring endometrial thickness is important in diagnosing uterine bleeding disorders or infertility.

Structure of the Endometrium

The endometrium consists of two layers:

Stratum basalis: The basal layer located nearest the uterine muscle; it remains intact during menstruation and enables regeneration.
Stratum functionalis: The functional layer, which thickens and sheds during the menstrual cycle and is responsible for implantation.

The Endometrium and Menstruation

In the absence of pregnancy:

1. Shedding: Estrogen and progesterone levels fall, leading to constriction of the blood vessels supplying the endometrium.
2. Bleeding: The functional layer becomes necrotic and detaches, resulting in menstrual bleeding.
3. Regeneration: The basal layer regenerates a new functional layer for the next cycle.

The Endometrium’s Role in Fertility

The endometrium is essential for conception and pregnancy:

• It thickens appropriately for implantation.
• Supports the attachment of the embryo.
• Provides early nutritional support.
• Helps maintain pregnancy until the placenta matures.

Conditions such as a thin endometrium, polyps, or fibroids may impair fertility.

Endometrial Disorders

Endometrial disorders involve abnormal growth of endometrial tissue:

Endometriosis: Endometrial tissue grows outside the uterus, causing severe pain, abnormal bleeding, and infertility.
Adenomyosis: Endometrial tissue grows within the uterine wall, leading to pain, heavy bleeding, and uterine enlargement.
Endometrial polyps: Benign growths in the uterus that may cause abnormal bleeding and sometimes infertility.
Endometrial hyperplasia: Abnormal thickening of the endometrium, often due to hormonal imbalance; a risk factor for endometrial cancer.
Menstrual retention syndrome: Accumulation of menstrual blood in the uterus due to cervical obstruction.

Treatment depends on severity and may include medication, surgery, or other management strategies.

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Everything You Need to Know About the Endometrium

If you have questions related to everything you need to know about the endometrium or would like recommendations on evaluating and monitoring your newborn during the first days of life, you may request an individual consultation at any time. A thorough assessment helps determine the most suitable monitoring and support plan for your child.

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