Endometrial Thickness: What Is The Normal Range?

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The endometrial lining of the uterus plays a key role in fertility. Any abnormality in the thickness of the uterine lining could lessen the chances of conception, which can be frustrating if you are planning to have a baby. However, with the many fertility treatments available today, there is hope for the couples dealing with it.

In this post, MomJunction tells you about the issues associated with the endometrium lining, its symptoms, and the ways to deal with it to improve the chances of conception.

What Is The Endometrium?

The endometrium is the inner lining of the uterus where the implantation of the embryo takes place (1). It comprises a single-layered prismatic epithelium and cell-rich connective tissue with blood vessels that surround the uterine glands. The single-layered prismatic epithelium consists of three types of cells: secretory cells, cells with cilia, and basal cells.

The endometrium undergoes various morphological and functional changes during menarche. As the level of sex hormones changes in the body during ovulation, the thickness of the endometrial lining also changes to enable the implantation of the fertilized egg. If fertilization doesn’t happen, then the endometrium lining (functional layer) sheds, leading to menstrual flow.

Note: The morphology and thickness of the endometrium remain constant before puberty and in menopause.

What Does The Endometrial Stripe Look Like?

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The endometrium looks like a stripe on an MRI or ultrasound scan. The stripe refers to the appearance and thickness of the endometrium lining that changes during the menstrual cycle.

Here is how the endometrium changes during the menstrual cycle (2):

• Menstrual and early proliferative phase: In this phase, it appears as a thin and bright echogenic stripe that consists of a basal layer with minimal fluid.

• Late proliferative phase: A trilaminar appearance is seen in this phase. It comprises the basal layer, middle functional layer, and the inner echogenic stripe at the center.

• Secretory phase: Endometrium is the thickest during this phase. The stripe has fluid surrounding it and thus looks uniformly echogenic in an ultrasound.

The following section explains the thickness of the endometrium during various stages of the menstrual cycle.

What Should The Thickness Of The Stripe Be?

Here is how the endometrium stripe’s thickness varies at different stages of the menstrual cycle in premenopausal women.

The endometrium thickness must be greater than 8mm for normal pregnancy (3). The pregnancy rate is negatively affected when the stripe’s thickness is less than 7mm (4).

What Causes Abnormally Thickened Endometrium?

Both pregnant and non-pregnant women can have an abnormally thickened endometrium due to various reasons (5).

In pregnant women, thickened endometrium could be due to:

• Ectopic pregnancy, which can make the endometrium look thick
• Pseudogestational sac
• Retained products of conception
• Heterogeneously thickened endometrium, which could be due to fluid collection
• Heterogeneously thickened endometrium due to an intrauterine blood clot
• Molar pregnancy, wherein the multiple small cystic spaces make the endometrium look thickened
• An inflammation of the uterus, also called as endometritis

In non-pregnant women, it could be because of:

• Endometrial carcinoma that gives it a thickened appearance
• Endometrial hyperplasia or over-thickening of the endometrium
• Endometrial polyp, or benign protrusions on the endometrial surface
• Tamoxifen-related changes causing variable appearances of the endometrial surface
• Endometritis

What Are The Symptoms Of An Abnormally Thick Endometrium?

The symptoms of an abnormally thick endometrium lining, also known as endometrial hyperplasia, include (7):

• Heavier bleeding during periods
• Longer periods than usual
• Menstrual cycle shorter than 21 days

For further diagnosis, consult your doctor.

How Is Abnormally Thick Endometrium Diagnosed?

Transvaginal ultrasound helps in identifying abnormal endometrium thickness. If you experience abnormal bleeding, which is uncontrollable by medication, then this diagnostic test is suggested (6).

How Is It Treated?

Abnormal thickening of the endometrium can be treated with progestin. It is given orally, as an injection, through an intrauterine device, or in the form of vaginal cream. The side-effects of progestin include vaginal bleeding, similar to that of the menstrual period (6).

Apart from thickening, endometrium lining could also become thinner than usual, yet another problem faced by many women. Find out more about it next.

What Causes Thinning Of The Endometrium?

Thin endometrium results from the impairment of the normal growth of the endometrial tissues. Its causes include (6):

• Permanent damage to the basal endometrium
• Resistance of estrogen by endometrium surface receptors
• Decreased blood flow to the endometrium
• Testosterone overexposure

These abnormalities can show up as various symptoms during your menstrual cycle. If you are dealing with the thinning of the endometrium, there are various methods to rectify the issue.

How To Increase Endometrial Thickness For Conception?

The thickness of the endometrium can be increased naturally by maintaining a balanced estrogen level. It can be achieved by ( (8) Pg 27, 166),

Engaging in moderate exercises like walking and yoga that help in pumping more blood in your body.
Following a healthy diet to maintain a healthy weight. Add cod liver oil, spirulina, and wheatgrass to your diet.
Avoiding environmental estrogen, which is found in birth control pills and beauty products.

The alternative methods mentioned below can also be used for increasing the endometrial thickness (6).

• Hormonal adjustment: It has been observed that administration of estrogen led to better development of the endometrium lining.

• Pentoxifylline and tocopherol: This combination, when administered in dosages of 400mg, has led to better development of the endometrium lining.

• Low-dose aspirin: It has shown a significant increase in the thickness of the endometrium lining.

• Acupuncture: It has been found that electroacupuncture helps in increasing the blood flow in the uterus and better growth of the endometrial lining.

• L-arginine: It helps in relaxing the vascular smooth muscles of the endometrium, thereby decreasing the resistive index.

• Nitroglycerine patch: It helps in increasing the uterine blood flow.

• Vaginal sildenafil: It has a significant effect on improving the thickness of the uterine lining.

• Stem cell therapy: Studies have established that the progenitor cells of endometrium play a role in increasing the endometrium thickness.

• Platelet-rich plasma: It has also been useful in correcting thin endometrium and reducing implantation failure.

Next, we address a few commonly asked questions about endometrial thickness.

Frequently Asked Questions

1. Can endometrial thickness indicate early pregnancy?

Yes. Endometrial thickness can indicate early pregnancy, be it normal or abnormal (ectopic). Most normal intrauterine pregnancies occur when the endometrium has a thickness of 13-25mm (9).

2. How much endometrial thickness is too much?

Usually, a thickness >25mm is considered too much as it results in abnormal pregnancy, such as ectopic pregnancy.

Endometrium lining issues are no longer untreatable these days. The ongoing research in the field of infertility has developed various alternatives for treating the problem, giving hope to the couples who have trouble becoming parents naturally.

Have you any experiences to share? Please share them in the comments section below.

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