Modern methods of embryo selection in the context of IVF

In order to increase the chances of a successful pregnancy within an in vitro fertilization (IVF) program, specialists in embryology laboratories use modern methods to select the most promising embryos. The main approaches include stepwise morphological assessment at key stages of development and preimplantation genetic diagnosis (PGD).

Steps in the Morphological Assessment of the Embryo

Assessment of the Zygote and Pronuclei

As early as 18 hours after the fertilization of the egg by the sperm, an initial assessment can be made: the pronuclei become visible under the microscope. A zygote should contain two pronuclei, which is considered a sign of successful fertilization.

Fragmentation Stage and Blastomeres

After 2 to 3 days of development, the segmentation of the zygote begins, and blastomeres, large and uniform cells, form. Embryologists assess the symmetry of division, the number of cells, and the presence of fragmentation, which can indicate developmental disorders and reduce implantation chances.

Morula Formation

On the fourth day, the embryo reaches the morula stage, counting 16 to 18 cells. During this period, the cells compact, intercellular spaces disappear, and the surface becomes smooth. Embryologists evaluate the degree of compaction and the symmetry of the morula structure.

Blastocyst Stage

On the fifth day, a cavity forms inside the morula, which should occupy at least 20% of the total volume. The embryo progresses to the blastocyst stage, consisting of two key structures: the trophoectoderm (which forms the placenta) and the inner cell mass (which gives rise to the tissues and organs of the future fetus). At this stage, specialists assess the size of the cavity, the homogeneity of the trophoectoderm, and the structure of the cell mass.

Continuous Monitoring: Embryoscopy with Time Lapse Technology

The "Natuvitro" clinic utilizes an embryoscope, which allows for 24-hour monitoring of embryo development in the incubator without removing them. The Time Lapse system takes a series of high-frequency photos and compiles them into a video. This enables tracking the development of each embryo over time and making more precise decisions based on a comprehensive picture of embryogenesis.

Preimplantation Genetic Diagnosis (PGD)

On the fifth day of development, an embryo biopsy followed by genetic analysis can be performed. PGD allows for the detection of chromosomal and monogenic abnormalities before the embryo transfer to the uterus. This is particularly important for couples with hereditary diseases, IVF failures, or age-related risks. Transferring a genetically healthy embryo increases the chances of successful implantation and reduces the risk of spontaneous miscarriage.

Considering the Specificities of Different Forms of IVF

Although the methods for assessing embryos remain universal, the type of biomaterial used can influence selection strategies:

• Classic IVF is performed using the eggs and sperm of the couple. The quality of the embryos depends on the individual characteristics of reproductive health.
• The IVF with donor eggs increases the chances of obtaining high-quality embryos through rigorous selection of donors based on their age and reproductive parameters. These embryos often exhibit better morphology and implantation potential.
• The IVF with double donation (donor eggs and sperm) ensures even higher quality control at all stages, promoting the acquisition of excellent quality blastocysts. Regardless of their origin, all embryos undergo the same morphological assessment and, if necessary, PGD.

These specificities are taken into account when planning treatment, but the main criteria for embryo selection - stability of division, minimal fragmentation, clarity of blastocyst structures, and genetic integrity - remain the same for all IVF programs.

Consultation and Individual Approach

To learn more about embryo selection methods and choose the optimal strategy, you can consult a specialist at the "Natuvitro" clinic. Experienced specialists will help you navigate the options offered by modern reproductive medicine and choose the most effective IVF program.