ЕRА® test

Endometrium and endometrial receptivity

One of the causes of infertility in women is the presence of a problem with the uterine lining. The inside of the uterus is a special layer, called an endometrium, which every month prepares for acceptance and implantation. If this does not happen, there is a menstruation or expulsion of the swollen endometrial mucosa. One of the extremely important factors for the implantation of the embryo in the endometrium is the endometrial receptivity. The endometrium is receptive, when it is ready for implantation of the embryo – which usually occurs between the 19th and the 5th day of the 7th and 21st. This period of receptivity is called “implantation window”.

What is ERA® (Endometrial Reserve Arrау)?

This is a diagnostic method for establishing the implantation window of the uterus – the moment in which the uterine lining is being prepared. The method is based on the measurement of the profile of the gene expression of the endometrial tissue.
ERA® is a new method, developed and patented after more than 10 years of research. This method helps evaluating on molecular level the status of endometrial receptiveness of the woman and provides information if the endometrium (uterine lining) has receptive profile around the 21-st day of the menstruation, when the endometrium is supposed to be ready for embyo implantation.

How does ERA® work?

In order to take a sample for analysis, a biopsy of the uterine mucosa is performed. Based on preliminary research, a day is determined in which to perform the endometrial biopsy. With the help of a special catheter, a small part of the endometrium is taken. The procedure is easy, fast and is performed by a gynecologist in an outpatient clinic.

The sample is tested by a highly specialized genetic analysis. It analyzes the expression of 238 genes, which determine the endometrium receptivity. A special software analyzes the collected information and classifies the endometrium as “receptive” or “non-receptive”.

Through this analysis, it can be determined whether the theoretically predicted implantation pattern of the woman’s uterus coincides with the actual implantation.

If they are equal the the implantation window of the woman is determined according the day of the biopsy, which means that the embryo can be implanted successfully  during this period.

If the condition of “non-receptivity” is determined, it means that the implantation procedure of the woman has been displaced. In this case, on the basis of the previous result, a new period of time is determined in which the biopsy must be repeated.Once the patient has been placed on the individual implantation site, the implant can already be successfully implanted.

What are the benefits of ERA®?

It has been established that in about 28.6% of women with reproductive problems, the theoretically predicted implantation procedure does not correspond to the current population. Therefore, before starting the in vitro procedure, it is desirable to determine through the diagnostic method EPA whether the patient has any implants in the patient.Taĸa мoгaт дa бъдaт пpeдпpиeти ĸopигиpaщи дeйcтвия, чpeз ĸoитo дa ce пoвиши шaнcът зa ycпeшнo лeчeниe чpeз мeтoдитe нa acиcтиpaнaтa peпpoдyĸция.

Absolute indications for ERA®:

  • Women up to 37 years of age, with at least three unsuccessful ETs of embryos with good morphological characteristics;
  • Women over 37 years of age with at least two unsuccessful ETs on embryos with good morphological characteristics.

Relative indications for EPA®:

  • Embryo transfer of embryos;
  • Availability of hydrocalping when tubing has a safety factor;
  • Endometriosis associated with infertility;
  • Congenital anomalies(utеruѕ dіdеlfuѕ);
  • Before starting treatment through an in vitro procedure. 

The ЕRА® diagnostic method helps to determine whether and when the uterine lining offers the ideal embryo implantation conditions allowing the embryo transfer to be performed at the most appropriate time, which tremendously increases the odds for success of every in vitro procedure.

ERA® use in Bulgaria:

For the first time in Bulgaria, the innovative ERA® method is used in Invitro Clinic ”SOFIA”.


Molecular test to determine the implantation window / ERA /

1250 BGN