Clinical pregnancy (CP) and live birth (LB) increase significantly with each additional fertilized oocyte up to nine, and CP and LB decline after that: an analysis of 15,803 first fresh in vitro fertilization cycles from the Society for Assisted Reproductive Technology registry.
OBJECTIVE: To study the association between the total number of fertilized oocytes available and pregnancy outcomes in first fresh IVF cycles with a single blastocyst transfer. DESIGN: Retrospective cohort study. SETTING: Not applicable. PATIENT(S): A total of 15,803 patients from SART reporting fertility clinics. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Primary outcomes were clinical pregnancy (CP), live birth (LB), and miscarriage rates. Logistic regression was used to investigate the association between the number of fertilized eggs and each outcome. RESULT(S): The median number of total oocytes was 15, and the median number of fertilized oocytes was nine. The odds of a clinical pregnancy were 8% higher for each additional fertilized oocyte up to nine (odds ratio [OR] 1.08; 95% confidence interval [CI] 1.07-1.10) and declined by 9% for every additional fertilized oocyte after nine (OR 0.91; 95% CI 0.89-0.94). Similarly, the odds of an LB was 8% higher for every additional fertilized oocyte up to none (OR 1.08; 95% CI 1.06-1.10) and declined by 8% for every additional fertilized oocyte over nine (OR 0.92; 95% CI 0.90-0.94). CONCLUSION(S): Odds of pregnancy outcomes (CP, LB) increase significantly with every additional fertilized oocyte up to nine, and CP and LB decline after that in first fresh autologous cycles with a single blastocyst transfer.
Smeltzer, S; Acharya, K; Truong, T; Pieper, C; Muasher, S
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