Aim: We investigated the cumulative probability of ongoing pregnancy in intracytoplasmic sperm injection (ICSI) cycles.
Methods: During a period of 6 years, 519 ICSI cycles were performed in 260 infertile couples at the Seoul National University Hospital. The cumulative rate of ongoing pregnancy (> or =12 weeks of gestation) was estimated by the Kaplan-Meier method.
Results: The cumulative ongoing pregnancy rate was 54.9% after six consecutive cycles of ICSI. The age of the female had a significant impact; after five consecutive cycles, cumulative ongoing pregnancy rate was 61.8% in < or =30 years of age, 51.7% in 31-35, and 15.3% in > or =36. There was no significant difference in the cumulative ongoing pregnancy rate between groups with severe male factor and previous unexplained low fertilization rate (< or =20%). Among the severe male factor group, cumulative ongoing pregnancy rate was not different according to the methods of sperm retrieval (surgically retrieved or ejaculated).
Conclusion: Intracytoplasmic sperm injection could be applied successfully both to severe male factor and patients with previous unexplained low fertilization rate. The origin of spermatozoa does not affect ICSI outcome in terms of cumulative probability of ongoing pregnancy.