Objective: To show the success of intracytoplasmic sperm injection (ICSI) in cases of a low number of oocytes retrieved.
Study design: 715 microinjection cycles, which were performed at our center, were analyzed retrospectively.
Results: Within the analyzed cycles, there were 50 cycles with less than four oocytes retrieved. Twelve, 18, and 20 cases were treated with one, two, and three oocytes, respectively. The rate of metaphase II oocytes injected and subsequently fertilized, and intact oocytes was similar in the three groups. The transfer rate was not significantly different from those cases with more than three oocytes (84% vs. 94%). Therefore, the rate of fertilization failure was not higher in the low-number group. The number of embryos transferred was statistically significantly lower in the group with one and two oocytes compared to the group with three oocytes (1, and 1.31 vs. 2.27; P < 0.01) and the group of all patients (2.63; P < 0.01), as well as between the group of less than four oocytes and all patients (1.63 vs. 2.63; P < 0.01). There was no statistically significant difference between the pregnancy rates of the three groups (36.4% vs. 20% vs. 22.2%), and also no difference was found between the group with less than four oocytes and the data of all patients (22% vs. 26.9%).
Conclusion: In our opinion, these data show that ICSI guarantees a successful treatment even if only as many oocytes are present as embryos are planned to be transferred, i.e. three embryos. This has been accepted to be a new indication in our center. Therefore it should be possible to stimulate patients mildly, with e.g. clomiphene citrate, to avoid unnecessary hyperstimulation syndromes, and to lower the cost of hormonal superstimulation.