Pre-implantation genetic testing alters the sex ratio: an analysis of 91,805 embryo transfer cycles.
PURPOSE: To determine if pre-implantation genetic testing (PGT) shifts the sex ratio (SER), the ratio of male to female births in a population normalized to 100 and typically stable at 105, following in vitro fertilization (IVF). METHODS: Data from 2014 to 2016 was requested from the Society for Assisted Reproductive Technologies (SART) database including fresh and frozen transfer cycles. Women with a singleton live birth following a fresh or frozen autologous embryo transfer of a PGT blastocyst, non-PGT blastocyst, or non-PGT cleavage stage embryo were included. The SER between groups was compared using chi-square tests. Modified Poisson regression modeled the relative risk (RR) of having a male compared to a female among PGT blastocyst transfers versus non-PGT cleavage and blastocyst transfers adjusting for age, BMI, smoking status, race, parity, number of oocytes retrieved, and clinic region. RESULTS: The SER was 110 among PGT blastocyst offspring, 107 among non-PGT blastocyst offspring (p = 0.005), and 99 among non-PGT cleavage offspring (p < 0.001). The risk of having a male infant was 2% higher among PGT blastocyst transfers compared to non-PGT blastocyst transfers (RR 1.02; 95% CI: 1.01, 1.04). The risk was 5% higher among PGT blastocyst transfers compared to non-PGT cleavage transfers (RR 1.05; 95% CI: 1.02, 1.07). The association between PGT and infant gender did not significantly differ by region (p = 0.57) or parity (p = 0.59). CONCLUSION: Utilizing PGT shifts the SER in the IVF population from the standard of 105 to 110, increasing the probability of a male offspring.
Shaia, K; Truong, T; Pieper, C; Steiner, A
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