The Endometrium is the lining of the Uterus and is an important function during the Female Reproduction process.

It is the innermost glandular layer of tissue that is found in the uterus. It has many different functions to help with the fertilization of an embryo and is an essential part of the menstrual cycle.

Function during Menstrual Cycle

–  This lining will thicken – likely in response to hormone-regulated controls.
–  Blood vessels enrich the wall
–  Addition of glandular tissue
–  It becomes optimal for potential Implantation of the egg when it arrives in the Uterus.
–  If no implant occurs – this lining will be released.

Function during Pregnancy

–  During Pregnancy the wall will continue to thicken
–  Blood vessels will enlarge and increase in number.
–  The Placenta is formed
–  Oxygen and nutrients are brought to the embryo.

The Endometrial Cycle

–  The lining goes through a cyclic regeneration process each month.
–  Endometrium is closely regulated or affected by Estrogen and Progesterone
–  Both are secreted in response to the release of an egg from the Ovaries.
–  The endometrium proliferates due to the increased amount of Estrogen.
–  Progesterone will also affect the layer or tissue in the Uterus.
–  When implantation occurs – the lining becomes known as decidua – which later becomes part of the placenta
–  The endometrium is now prepared for implantation.
–  The cycle of building the endometrial lining takes on average 28 days.
–  Different mammals are on different lengths of the cycle.
–  Seasons, stress, medications, drug use, and other factors can disrupt or change this cycle.


–  This is when the endometrial lining does not thicken.
–  Often associated with lack of hormones or other causes
–  No menstrual period is often the result


–  Menopause is when the lining of the endometrium becomes atrophic
–  No continued menstrual periods will occur.
–  Physically unable to become pregnant after this moment
–  Also related to hormones.

Oral Contraceptives

–  This is Medication to stop pregnancy
–  It specifically causes/targets hormone changes that don’t allow for Endometrial growth.