Thin Endometrium

What is a thin endometrium?

The endometrium is the lining of the womb, where an embryo implants. It thickens in the first half of the menstrual cycle under the influence of estrogen. A lining that measures less than about 7 mm on ultrasound at the time of ovulation or before embryo transfer is usually described as thin. A thin lining is linked with lower implantation and pregnancy rates, although pregnancies do occur with thinner linings.

Symptoms and signs

• Very light or scanty periods, or periods that have become much lighter than before
• Absent periods in severe cases
• Repeated failed IVF cycles or embryo transfers that are cancelled because the lining is too thin
• Recurrent miscarriage in some women

Many women have no symptoms, and the problem is found during fertility scans.

Causes and risk factors

• Scarring of the womb lining (Asherman syndrome) after D&C, surgical abortion, retained pregnancy tissue or postpartum infection
• Genital tuberculosis, an important cause in India
• Chronic endometritis
• Low estrogen levels, as in low ovarian reserve or hypothalamic amenorrhoea
• Side effect of clomiphene, which can thin the lining
• Previous uterine surgery or pelvic radiation
• Reduced blood flow to the uterus

How it is diagnosed

• Serial transvaginal ultrasound scans to measure lining thickness and pattern
• 3D ultrasound or saline sonography to look for adhesions
• Hysteroscopy, which shows the cavity directly and can treat adhesions
• Endometrial biopsy with tests for tuberculosis (such as GeneXpert or culture) and chronic endometritis where indicated
• Hormone tests including estradiol, FSH, AMH, thyroid and prolactin
• Doppler ultrasound to assess blood flow in some cases

Treatment options

Treating the underlying cause

Hysteroscopic adhesiolysis removes scar tissue in Asherman syndrome. Genital tuberculosis needs a full course of anti-tubercular treatment, and chronic endometritis is treated with antibiotics.

Estrogen therapy

Estrogen given by tablet, vaginally or through the skin, often for a longer duration, can help the lining grow. In IVF, a frozen embryo transfer in a medically prepared cycle allows more control over lining development.

Changing medicines

Switching from clomiphene to letrozole for ovulation induction can help when clomiphene is thinning the lining.

Other approaches

Treatments such as vaginal sildenafil, G-CSF, platelet-rich plasma (PRP) and stem cell therapy have been studied, but evidence is limited and they are considered experimental. Your specialist will discuss whether any are appropriate.

Gestational surrogacy

For the small number of women whose lining cannot be improved despite treatment, gestational surrogacy may be discussed within the rules of the ART and Surrogacy Acts in India.

Chances of pregnancy

Many women with a thin lining achieve pregnancy once the cause is treated and the lining improves. Women with severe scarring may need more than one procedure. Overall chances depend on the cause, age and embryo quality, and no outcome can be guaranteed.

When to see a fertility specialist

See a specialist if your periods have become very light after a D&C or infection, if a scan shows a thin lining, or if an IVF transfer has been cancelled or failed because of the lining. Iswarya Fertility offers hysteroscopy and IVF care across its 91+ centres.