Volume 112, Issue 3, Pages 520–526.e1
Stephanie Smeltzer, M.D., Kelly Acharya, M.D., Tracy Truong, M.S., Carl Pieper, Ph.D., Suheil Muasher, M.D.
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.
Retrospective cohort study.
A total of 15,803 patients from SART reporting fertility clinics.
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.
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).
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.