Conventional IVF improves blastocyst rate and quality compared to ICSI when used in patients with mild or moderate teratozoospermia

The ICSI procedure was invented to treat severe male infertility but is often used even if the sperm quality parameters are normal. This practice has recently been called into question, but there is still no clear answer especially in terms of sperm morphology, regarding when it is necessary to perform ICSI and when conventional IVF is indeed more beneficial. In borderline cases it seems logical to fertilize oocytes using ICSI and conventional IVF at the same time. Since we also use this approach we performed a retrospective analysis of such cycles to elucidate, which procedure results in a better clinical outcome in terms of fertilization rate, the quality of day 3 and day 5 embryos, and the pregnancy rate. The data from fifty-one couples who were treated with ART and whose male factor of infertility was defined as teratozoospermia were included. The fertilization rates were similar between ICSI and conventional IVF groups (per COCs: 54.5% vs. 58.2%, P = 0.322; per MII oocytes: 63.9% vs. 67.2%; P = 0.399), but more oocytes degenerated after ICSI (11.7% vs. 4.3%; P = 0.0003). The quality of cleaved embryos was similar between the groups, but more embryos reached the blastocyst stage after conventional IVF (43.7% vs. 55.0%; P = 0.032) and furthermore, more of them were of good quality (19.8% vs. 29.2%; P = 0.037). The pregnancy rate did not significantly differ between the groups (21.4% vs. 45.5%; P = 0.175), although there was a trend in favor of conventional IVF. This retrospective analysis suggests that when sperm morphology is not severely impaired and sperm concentration and motility are normal, it is better to use conventional IVF to fertilize oocytes and not ICSI. The main advantage of conventional IVF is reflected in improved blastocyst rate and quality.