Does ICSI timing affect pregnancy outcomes?

This study looked at routine variations in timing during intracytoplasmic sperm injection (ICSI). It found that changes in timing may affect egg quality, but did not alter pregnancy outcomes.

ICSI is an infertility treatment in which a single sperm cell is injected into the oocyte (egg). ICSI is most commonly used for male factor infertility. First, medications stimulate the ovaries to produce multiple follicles. When the follicles reach the correct size, a hormone injection is given. This injection triggers the follicles to mature so the eggs can be collected. A needle is inserted through the abdomen to collect the oocytes. Oocytes are covered by a protective layer of cells that release hormones that influence fertilization. These cells are removed from the oocyte using chemicals and/or small pipettes, a process called denudation. A sperm cell is then injected into the denuded oocyte.

The timing between these steps in the ICSI process varies depending on the schedule and workload of the laboratory. However, the oocyte has a short lifespan during which it can be fertilized. It is unclear whether ICSI timing affects oocyte quality or reproductive outcomes.

This study included 613 cycles of ICSI. The timing of ICSI steps was done according to the clinic’s routine management and workload, and the times were recorded.

Oocyte collection occurred between 35 and 39 hours after the trigger injection. Oocytes which were collected more than 36 hours after the injection more often contained abnormal particles. These particles included granulation and inclusion bodies. A longer time period between denudation and ICSI was also significantly related to abnormal particles. However, there was no difference in the fertilization rate or pregnancy rate.

This study found that a longer period of time between ICSI steps may have an effect on oocyte quality. However, there was no impact on pregnancy rates.

Randomly assigning times would better test differences due to ICSI timing. However, this study has the advantage of real-world conditions in a fertility clinic.