An excellent rate of pregnancy after an IVF cycle is around 60%. But even in the very successful units, some couples fail repeatedly. In these cases it produces an IVF Implantation Failure.

IVF Implantation failure

The implantation failure is defined by patients who are transferred at least 6 good quality embryos on 2 or 3 transfers without falling pregnant.

Naturally we are a species with low reproductive efficiency as the implantation rate is approximately 35%, the remaining 65% of embryos not implanted are divided equally into two groups, embryos with anomalies, and interactions between endometrial and altered embryo.

When we speak of assisted reproduction, this percentage of anomalous interaction between endometrium and embryo is larger, becoming 43% in cases of invitro fertilization and 38% in cases of egg donation.

The problems may be caused on

  • an endometrial level,
  • irregular anatomy of the uterus,
  • a non-responsive and endometrium thrombophilia
  • immunological disorders.

If the embryo is not good quality, the interactions may not develop properly and the deployment process occurs.

New genetic test for the study of the implantation window

We know that the endometrium is only receptive during the period called the implantation window. This period is between the 6th and 7th day after ovulation.

Strategies for studying endometrial dating were described by Noyer in 1950. It is based on morphological criteria, so there is great variability between both the intra- and interobserver intercycle. The study of the implantation window using this technique have shown a similar proportion of women either fertile or not, out of phase endometrium, 49% versus 43%, respectively.

With the development of new technologies, we have entered the era of genomics and functional genomics specifically, studying the messenger RNA expressed by certain genes.

In our VITA Reproductive Medicine clinics, our patients can take a genetic test that will evaluate the expression of 238 genes, allowing us to study the molecular profiles during the receptive or prereceptive periods. This technique has been demonstrated that each phase of the menstrual cycle has a characteristic and unique profile gene expression, allowing endometrial dating without error.

This biopsy is done in consultation quickly and easily. Thereby determining whether we are in the window of implantation or if this is off.

Knowing the time which the endometrium is receptive, the expression can be modified by varying the day of administration of progesterone and can thus convert a receptive endometrium prereceptive.

The ERA test is for women diagnosed with implantation failure, an apparently normal uterus and normal endometrial thickness.

The diagnosis is only valid for the type of cycle in which the test is performed, therefore embryo transfer must be performed on the same type of cycle, as it has been observed in some patients that the receptivity can vary depending on the type of cycle.