This study aims to investigate the effects of trophectoderm (TE) biopsy on the health and development of children born after preimplantation genetic testing (PGT) cycles. The blastocyst biopsy is performed as part of standard clinical practice, in accordance with established protocols and current national regulations governing assisted reproduction.

Inclusion Criteria for Cases:

• Child: Has completed the first year of life at the time of data collection.
• Child: Does not have any pre-existing medical conditions that significantly affect growth (weight and height).
• Mother: Able to provide informed consent for participation in the study.
• Mother: Conceived between the ages of 18 and 43.
• Mother: Achieved a singleton live birth with a single gestational sac.
• Mother: Underwent a PGT cycle followed by FET.

Inclusion Criteria for Controls:

• Child: Has completed the first year of life at the time of data collection.
• Child: Does not have any pre-existing medical conditions that significantly affect growth (weight and height).
• Mother: Able to provide informed consent for participation in the study.
• Mother: Conceived between the ages of 18 and 43.
• Mother: Achieved a singleton live birth with a single gestational sac.
• Mother: Underwent only FET.

Participants will be excluded from this study if they meet any of the following criteria:

• Mother: Unable or unwilling to sign the informed consent.
• Mother: Has undergone a fresh embryo transfer.
• Child: Missing birth weight or length/height data.

The study will involve a total of 330 children born as single live births after their mothers underwent assisted reproduction technology (ART) treatment. The participant population includes:

• Cases: 110 children born as single live births after their mothers underwent a PGT cycle followed by frozen embryo transfer (FET).
• Controls: 220 children born as single live births after their mothers underwent only FET.