Microinjection of human oocytes: a technique for severe oligoasthenoteratozoospermia

Abstract

Objective: To determine outcome after microinjection with very poor quality sperm and after failed fertilization.

Design: Group 1, fresh oocytes from patients with very low sperm density and motility on the day of oocyte recovery; Group 2, 1-day-old oocytes that failed to fertilize.

Setting: All material was obtained from the National University Hospital.

Patients: One hundred and thirty-one from group 1; 35 from group 2.

Interventions: Sperm was injected subzonally or directly into the ooplasm.

Main outcome measure: Normal and abnormal fertilization and pregnancy.

Results: Subzonal transfer was done on 771 oocytes in group 1 and 188 oocytes in group 2. Multiple sperm were transferred [mean of 6.6 for group 1 and 7.3 for group 2]. Monospermic fertilization occurred in 16.6% and 14.9%, respectively. Polyspermy and parthenogenetic activation were low at 2.3% and 2.8%, respectively. Five pregnancies were obtained, but only one delivered. Ooplasmic injection (single sperm heads) was done in 38 oocytes from three patients with extremely severe oligozoospermia; only four two-pronuclear zygotes were obtained and replaced into two patients, without any resulting pregnancy.

Conclusions: Subzonal transfer may be a viable technique for patients with severe sperm problems.