Thin Endometrium

What is Thin Endometrium?

Most studies state an endometrium of less than 7 mm is considered as Thin Endometrium.

https://pubmed.ncbi.nlm.nih.gov/30239738

How is Endometrium measured?

Maximal distance between echogenic interfaces of endometrium and myometrium in plane of central longitudinal axis of the uterus. This is best measured by a transvaginal endometrium with empty bladder around the 15th to 18th day of the menstrual cycle.

Is it impossible to have pregnancy with Thin Endometrium?

Though rare, live birth rate 15% in Fresh IVF where ET was between 5-6mm And FET where ET was between 4-6mm have been reported.

https://pubmed.ncbi.nlm.nih.gov/30239788/

How common is thin endometrium in fertility treatment?

It is fairly common. It can be seen as high as 30% in ovarian stimulation cycles.

Is thickness of the endometrium the only factor in deciding prognosis?

No, pattern of endometrium is also important. Though many centers do doppler scans too , we fee,l it may help in diagnosing reduced uterine blood flow, whose treatment remains aspirin and LMWH which is already given in most situations whenever thin endometrium is encountered. Also, it is time taking, expensive and highly user dependant.

What are the patterns of the endometrium?

1. Grade A – Triple Layer
2. Grade B – Intermediate echogenicity as myometrium
3. Grade C – Homogenous hyperechoic
4. Endometrial pattern is sometimes a better indicator of the probability of pregnancy than thickness. Trilaminar pattern with ET ≥6 mm suggests that implantation may not be compromised

What are the causes of Thin Endometrium?

1. Acute or chronic infection: which leads to destruction of the basal layer of the endometrium.
2. Repeated or vigorous curettage
3. Aggressive myomectomy
4. Partial ablation
5. Radiotherapy
6. Medical treatment like Clomiphene Citrate, Prolonged progesterone therapy and Combine Oral Contraceptive Pill
7. Congenital malformations of uterus may be associated with sub- optimal ET
8. Idiopathic- where cause is undiagnosed

What is the treatment of Thin Endometrium?

1. Hysteroscopic adhesiolysis
2. Treating Infections
3. Hormonal manipulation
   • Estrogen: PO, transdermal, IM and vaginal
   • HCG injection in the proliferative phase
   • Midluteal GnRHa
4. Improving endometrial perfusion
   • Aspirin
   • Sildenafil
   • L-arginin
   • Nitroglycerin
5. New modalities
   • Granulocyte colony-stimulating factor
   • Autologous platelet-rich plasma
   • Endometrial stem cells from bone marrow