A high oocyte yield for intracytoplasmic sperm injection treatment is associated with an increased chromosome error rate.

Objective: To compare the chromosome error rate among oocytes from stimulated ovaries after retrieval of 1-5 oocytes, 6-10 oocytes, and >10 oocytes.

Design: Retrospective cohort study.

Setting: A university-based human genetic institute in collaboration with a private fertility center.

Patient(s): Nine hundred thirty-three women undergoing intracytoplasmic sperm injection (ICSI) with a poor prognosis.

Intervention(s): Oocyte collection with ovarian stimulation. Polar body testing of ICSI oocytes for common chromosome errors.

Main Outcome Measure(s): Chromosome error rate in oocytes, as determined by five-color fluorescence in situ hybridization.

Result(s): In women less than 35 years and women between 35 and 40 years undergoing the first ICSI cycle, oocytes from the high-yield group had an increased likelihood for detectable chromosome errors (50.9% and 54.6%, respectively), compared to the intermediate-yield group (34.9% and 43.8%) and the low-yield group (23.3% and 41.2%). The overall high rate (>or=50%) of chromosomally abnormal oocytes in women more than 40 years appeared to be mainly due to the maternal age effect and increased only slightly with oocyte yield.

Conclusion(s): Oocyte yield may be considered as an indicator of ovarian response to hormone stimulation. In women up to 40 years a high yield of oocytes after superovulation is associated with an increased chromosome error rate.