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Preimplantation Genetic Testing (PGT) – Selection of Embryos with the Highest Implantation Potential

1. Preimplantation genetic testing is an advanced genomic tool used in IVF procedures to identify embryos free of genetic or chromosomal abnormalities prior to uterine transfer.

· PGT-A (Preimplantation Genetic Testing for Aneuploidy) Detects chromosomal aneuploidies, which are numerical abnormalities that can compromise embryo viability. PGT-A reduces miscarriage risk and increases the likelihood of achieving a singleton, healthy live birth. Indications include advanced maternal age, recurrent pregnancy loss, implantation failure, or severe oligozoospermia.

· niPGT-A (Non-Invasive PGT-A) Based on the analysis of cell-free embryonic DNA present in the spent culture medium of blastocysts, thus avoiding the need for trophectoderm biopsy. NiPGT-A is an alternative that allows continued in vivo development.

· PGT-M (for Monogenic Disorders) Enables selection of embryos unaffected by specific monogenic disorders previously identified in the family. This requires prior genetic work-up (family-specific test design) and is used in conditions such as cystic fibrosis, Duchenne muscular dystrophy, or spinal muscular atrophy (SMA).

· PGT-SR (for Structural Rearrangements) Intended for couples in which one partner carries a balanced chromosomal rearrangement, such as a translocation or inversion. PGT-SR prevents the transfer of embryos with unbalanced rearrangements, reducing the risk of miscarriage or serious congenital anomalies.

Semen and Endometrial Microbiome – The Role of the Microenvironment in Reproductive Success

2. The microbiological composition of semen and the endometrial lining plays a critical role in gamete quality, immunological balance, and embryo implantation. Dysbiosis—either in semen (e.g., pathogenic overgrowth) or endometrium (e.g., reduced Lactobacillus level)—may impair fertility outcomes and contribute to recurrent miscarriage. Microbiome diagnostics enable targeted modulation using probiotics, antibiotics, or immunotherapy, thus optimizing conditions for conception.

Endometrial Receptivity Testing – Personalizing the Timing of Embryo Transfer

3. Endometrial receptivity testing identifies the so-called „window of implantation” (WOI)—the optimal period during which the endometrium is most receptive to embryo implantation. Through gene expression profiling of endometrial biopsies, the test allows for precise timing of embryo transfer in hormone-prepared or natural cycles. This personalized approach has been shown to significantly improve implantation and pregnancy rates, particularly in patients with repeated failed transfers of euploid embryos.