Sex ratio of infants born through in vitro fertilization and embryo transfer: Results of a single-institution study and literature review

Objective: The possible effects of Assisted Reproductive Technology (ART) on sex ratio at birth are extremely significant. This study aimed to determine whether ART affects the sex ratio of infants born through in vitro fertilization and embryo transfer (IVF-ET). Materials and Methods: We ran this retrospective study on 290 singleton infants born following IVF-ET from February 2014 to August 2018 at a single institution. We compared the sex ratios of these infants with respect to insemination versus intracytoplasmic sperm injection (ICSI), early-cleavage embryo versus blastocyst transfer, fresh versus frozen-thawed embryo transfer and normal sperm versus asthenospermia. Results: There were no significant differences in the sex ratio with respect to the fertilization method, transfer time, fresh embryo or frozen-thawed embryo transfer. In addition, the multiple logistic regression analysis revealed that these factors did not significantly affect the sex ratio. Conclusions: Our study indicated that the differences in the fertilization method transfer time and sperm motility rate did not affect the sex ratio of IVF live births. However, with increasing numbers of ICSI and blastocyst transfer cycles, factors possibly affecting the sex ratio need to be further investigated.