The "freeze-all" strategy seems to improve the chances of birth in adenomyosis-affected women.

Objective: To compare assisted reproductive technologies (ARTs) outcomes between fresh vs. freeze-all strategies in infertile women affected by adenomyosis.

Design: A single-center observational study.

Settings: University hospital-based research center.

Patients: Adenomyosis-affected women undergoing blastocyst embryo transfer after in vitro fertilization and intracytoplasmic sperm injection between January 1, 2018, and November 31, 2021. The diagnosis of adenomyosis was based on imaging criteria (i.e., transvaginal ultrasound and/or magnetic resonance imaging).

Intervention(s): Women who underwent a freeze-all strategy were compared with those who underwent a fresh embryo transfer (ET) strategy.

Main Outcome Measure(s): Cumulative live birth rate (LBR).

Results: A total of 306 women were included in the analysis: 111 in the fresh ET group and 195 in the freeze-all group. The adenomyosis phenotype (internal diffuse adenomyosis, external focal adenomyosis, and adenomyoma) was not significantly different between the two groups. The cumulative LBR (86 [44.1%] vs. 34 [30.6%], respectively), and the cumulative ongoing pregnancy rate (88 [45.1%] vs. 36 [32.4%], respectively) were significantly higher in the freeze-all group compared with the fresh ET group. After multivariate logistic regression analysis, the freeze-all strategy in women with adenomyosis was associated with significantly higher odds of live birth compared with fresh ET (odds ratio = 1.80; 95% confidence interval = 1.02-3.16).

Conclusion: The freeze-all strategy in women afflicted with adenomyosis undergoing ART was associated with significantly higher cumulative LBRs. Our preliminary results suggest that the freeze-all strategy is an attractive option that increases ART success rates. Additional studies, with a randomized design, should be conducted to further test whether the freeze-all strategy enhances the pregnancy rate in adenomyosis-affected women.