Objective: To determine possible effects on chromosomal status of human oocytes in vitro.
Design: A prospective cytogenetic study of human oocytes fixed at 4, 20 (noninseminated oocytes), or approximately 52 hours after pick-up (inseminated-unfertilized oocytes).
Setting: Primary treatment of infertility in an institutional practice.
Patients, participants: Eighty-eight consecutive in vitro fertilization (IVF) patients (262 inseminated-unfertilized oocytes) and 47 IVF patients with greater than 8 oocytes retrieved (95 noninseminated oocytes).
Interventions: Ultrasound-guided transvaginal follicular aspiration.
Main outcome measure(s): Planned before data collection began.
Results: The incidence of chromosome anomalies did not differ between groups. However, a negative correlation between oocytes apparently without chromosomes and oocytes with fragmented chromosomes was found.
Conclusions: Incubation of oocyte in vitro does not affect the chromosome complement. The mechanisms leading to oocytes apparently without chromosomes and with fragmented chromosomes are self-excluding.