A freeze-all strategy does not increase live birth rates in women of advanced reproductive age

Does a freeze-all strategy improve live birth rates in women of different age groups?

Retrospective cohort study of 1882 first embryo transfer cycles, performed between January 2013 and December 2015. Reproductive outcomes between fresh (FRESH) or frozen (FROZEN) embryo transfers were compared in patients stratified by age: < 35, between 35 and 38, or > 38 years. Student's t test for independent samples and χ² analyses were used as needed. A multivariable logistic regression analysis was performed adjusting for age, triggering drug, number of retrieved oocytes, number of transferred embryos, and percentage of top-quality embryos.

Live birth rates (LBR) were significantly higher for FROZEN in the < 35 years group (43.7% vs 24%; p < 0.001). In both the 35-38 and > 38 years groups, LBR for FROZEN vs FRESH were not statistically different (30.9% in the FROZEN group vs 29.3% in the FRESH group, p = 0.70, and 19.8% in the FROZEN group vs 12.7% in the FRESH group, p = 0.07, respectively). The multivariate analysis found a significantly positive effect of performing FROZEN on LBR in the younger group (OR 2.46, 95% CI 1.31-4.62; p = 0.005) but had no impact in women between 35 and 38 years (OR 1.01, 95% CI 0.55-1.83; p = 0.98) or older (OR 0.96, 95% CI 0.43-2.13; p = 0.92).

Performing a freeze-all strategy seems to result in better reproductive outcomes when compared with a fresh ET in women under 35 years, with no significant impact on older women.