Evaluating the relationship between ejaculatory abstinence and the incidence of embryo mosaicism

To elucidate if differences in ejaculatory abstinence (EA) intervals are associated with the incidence of embryo mosaicism.

Retrospective cohort study.

Patients who received care within a nationwide fertility network underwent preimplantation genetic testing for aneuploidy from December 2019 to August 2022 with no known history of male factor infertility.

Patients were grouped by EA interval: 0-1 days (Group 1), 2 days (Group 2), 3 days (Group 3), 4 days (Group 4), 5 days (Group 5), and 6-10 days (Group 6) MAIN OUTCOME MEASURES: Primary outcome was the rate of embryo mosaicism. Secondary outcomes included sperm concentration and motility in the sample used at the time of in vitro fertilization, euploid rate, and aneuploid rate. Demographics and cycle characteristics were compared using a regression model fitted with generalized estimating equations. Risk ratios and 95% confidence intervals were estimated using Poisson regression models fitted with generalized estimating equations adjusted for male age, oocyte age, body mass index, antimüllerian hormone level, peak estradiol level, PGT lab, and year of treatment.

A total of 2,385 cycles were evaluated. Most cycles (n = 939, 39.4%) occurred in patients with an EA of 2 days. There was no difference in median baseline demographics or cycle characteristics. Median sperm concentration was significantly different between groups. Median sperm motility was similar in groups. Using Group 4 as a reference point, adjusted analysis for confounders with a 95% confidence interval showed no differences in the odds of developing mosaic (1.16 [0.79, 1.70], 1.10 [0.89, 1.37], 1.07 [0.86, 1.34], 1.05 [0.77, 1.43], 0.89 [0.45, 1.76]), euploid (0.80 [0.69, 0.92], 0.98 [0.93, 1.05], 1.00 [0.94, 1.06], 1.09 [1.00, 1.19], 0.99 [0.87, 1.12]), or aneuploid (1.14 [1.03, 1.27], 1.01 [0.94, 1.08], 1.01 [0.94, 1.08], 0.88 [0.79, 0.98], 1.00 [0.88, 1.13]) embryos in Groups 1-3, 5, and 6.

Although factors such as sperm concentration may be influenced by EA, interval variation does not appear to be associated with embryo mosaicism. Thus, couples undergoing in vitro fertilization can be reassured that moderate differences in EA are unlikely to be associated with embryonic mosaicism.