What is Low Uterine Receptivity?
Low uterine receptivity is defined as a decline in the uterus’ ability to host an implanted embryo or developing pregnancy.
Embryonal implantation is the process by which an embryo at the blastocyst stage (five to six days after fertilisation) binds to a mucous membrane which lines the uterine cavity called the endometrium and then develops prenatally.
Embryos are predominantly inserted into the middle or upper third of the uterine cavity at a particular point in the menstrual cycle medically referred to as an ‘implantation window’.
At this juncture in the process, a complex relationship between the developing embryo and the endometrium is established.
It is within this relationship morphological or functional alterations of the endometrium can affect the embryonic implantation process and development of pregnancy.
How does low uterine receptivity affect pregnancy?
Low endometrial or uterine receptivity are among the causes of female sterility and can lead to repeated embryonic implantation failures.
Causes of low uterine receptivity
Factors contributing to low uterine receptivity can vary, and in particular cases, several endometrial pathologies may coincide which can prevent embryonic implantation.
Possible causes of low uterine receptivity:
- Intrauterine pathologies such as polyps, myomas, partitions and synecias
- Infectious or inflammatory conditions such as endometritis and hydrosalpinx
- Defective growth of endometrium or overly narrow endometrium without sufficient thickness for embryonic implantation
- Displaced implantation window
- Intrauterine microbiota alterations (microbiota is a set of microorganisms that are generally associated with healthy tissues such as Lactobacillus predominates in the vagina and uterus)
- Thrombophilia (coagulation disorders)
- Systemic immunological diseases
What tests can be done to assess the endometrium?
Among the most common and effective tests of studying the endometrium is transvaginal ultrasound, in addition to being used to diagnose polyps, myomas, uterine malformations, hydrosalpinx and aid in the assessment of endometrial thickness.
The optimal endometrial thickness for embryonic implantation is between eight and 12mm accompanied by a trilaminar pattern. An endometrium of less than seven millimetres and greater than 17 mm in thickness usually has a lower implantation rate.
Sonohysterography: A transvaginal ultrasound administered using a saline solution in the uterus. Sonohysterography is regarded as a very useful uterine cavity study.
Hysteroscopy: This is a clinical procedure is used to further examine the uterine cavity by endoscopy, in addition to assisting in resecting polyps, myomas, sinechias and uterine partitions. The test is also used to confirm the diagnoses by pathological anatomy.
The Endometrial Receptivity Array (ERA) test uses DNA chips to determine the pattern of endometrial gene expression. The objective is to detect its receptivity or a potential pathology of endometrial origin.
Endometrial microbiota analysis aims to specify uterine microflora and treat imbalances.
Assisted human reproduction treatments in the event of low uterine receptivity
In the case of low uterine receptivity and repeated implantation failures, in vitro fertilisation is regarded as the most appropriate treatment.
Extensive testing and medical examinations are required prior to any treatment in order to better understand the cause of low endometrial receptivity.
Prescriptions administered to improve uterine receptivity are:
- Aspirin in low doses and heparin prophylactic in the case of thrombophilia diagnosis.
- Oestrogen during ovarian stimulation cycles in addition to endometrial preparation ahead of an embryo transfer.
- Vaginal sildenafil improves endometrial vascular flow and increases thickness.
- Vitamin E also enhances vascular flow in various organs and is recommended in cases involving narrow endometriums.
- If a displaced ” implantation window” is detected with a ERA test, an embryo transfer should be programmed at another point in the cycle where the greatest endometrial receptivity is understood to exist.
- Should a patient have an infection such as endometritis, it should be treated with a prescribed course of antibiotics before undergoing any procedure.
- Endometrial scratching is an additional surgical procedure available which can heighten receptivity by causing damage to the endometrium in order to then regenerate it.
Finally, you have to maintain healthy lifestyle habits and a healthy and balanced diet, which will always help improve health and facilitate the arrival of the desired pregnancy.
We hope that this new entry in our blog has helped you to solve your doubts about the Causes of Low Uterine Receptivity, while should you have any questions for our team of fertility specialists please don’t hesitate to request a free medical consultation..
A hug from the whole team,
Mallorca Fertility Institute