In vitro maturation (IVM) aims at achieving the final maturation of eggs within the laboratory with ultimate target their optimal fertilization. The immature eggs are obtained by puncturing follicles of small diameter. A similar method involves in vitro maturation of primordial follicles derived from frozen-thawed strips of ovarian tissue, in order to isolate and mature the enclosed oocytes.

In the first method (IVM), maturation only takes a few days, while the second (primordial follicle growth) requires special systems of extended culture. In both cases, the ultimate goal is the production of fully mature fertilizable eggs.

The method is quite promising in the field of ART, especially for special groups of women (e.g. women wishing to secure their fertility potential at a young age by freezing ovarian tissue for use later in life).

For now, the method is still at an experimental stage and its efficacy is limited. The main interests of IVM research groups are the enhancement of collection of immature egg from small follicles, improvement of culture conditions and guarantee that in vitro matured eggs are healthy and normal.

During natural conception, the blastocyst hatches from the embryonic shell, the zona pellucida, on the 5th or 6th day after fertilization. The fully hatched blastocyst is the last free-form embryonic stage and the only stage when the embryo has the capacity to attach and implant in the endometrium. However, in some cases, the zona pellucida is harder or thicker than normal, obstructing the process of hatching and, as a result, impairing successful implantation.

Hatching blastocysts after thawing.
Following an artificial opening on the zone pelloucida using laser the blastocysts have started to hatch.

When the embryos develop in culture, there is another possible intervention before the embryo transfer; the embryologist can assist blastocyst hatching by opening a small hole on the zona pellucida (assisted hatching), using either a special laser device or a chemical solution.

The initial excitement over the usefulness of assisted hatching in implantation has not been widely accepted by embryologists. The method does not seem to significantly increase implantation rates, while it subjects the embryos to further stress. However, assisted hatching has been proven to slightly improve implantation in special cases, such as thick zona, frozen-thawed embryos, eggs from women of increased age, etc.

Eugonia offers the assisted hatching method with the use of laser, in the cases that is has been deemed necessary by our scientific team.

New generation culture media have an improved and complex composition that perfectly supports the embryo during its pre-implantation development in the laboratory. More specifically, for the prolonged culture for 5 or 6 days, up to the blastocyst stage, the so-called sequential culture media are used, as they have different components reflecting the continuously changing nutritional and metabolic requirements of the developing embryo.

Recently, new culture media have developed that contain special growth factors (e.g. GM-CSF) which seem to significantly benefit patients with previous miscarriages and possibly patients with previous failed assisted reproduction cycle attempts, poor sperm quality, etc.

The advances in the culture media field have contributed significantly to the increase in pregnancy rates.

During the last years, molecular techniques that offer additional information on the viability and developmental potential of embryos have shown great advancement in the assisted reproduction field. These techniques, due to their name, have been included in the "omics" group.

They involve the study of the entire profile of the embryo's activity on various levels of expression (DNA, RNA, proteins or metabolites). Thus, the study of the entire genome is called genomics, the study of RNA transcription is called transcriptomics, of protein translation, proteomics and the study of the metabolism is called metabolomics.

These techniques, which are either invasive (genomics, transcriptomics) or non-invasive (proteomics, metabolomics) form the spearhead of research and some are already applied in the embryology laboratory. They are expected to play a pivotal role in objectively determining the developmental potential of each embryo so as to select one healthy embryo for transfer and increase pregnancy rates.