Intracytoplasmic sperm injection versus conventional in vitro fertilisation in couples with males presenting with normal total sperm count and motility

BACKGROUND: Starting over 40 years ago, in vitro fertilisation (IVF) has become the cornerstone for fertility treatment. Since then, in 1992, Palermo and colleagues successfully applied the technique intracytoplasmic sperm injection (ICSI) to benefit couples where conventional in vitro fertilisation (c-IVF) and sub-zonal insemination (SUZI) proved unsuccessful. After this case report, ICSI has become the treatment of choice for couples with severe male factor subfertility. Over time, ICSI has been used in the treatment of couples with mild male and even unexplained infertility. This review is an update of the review, first published in 1999, comparing ICSI with c-IVF for couples with males presenting with normal total sperm count and motility.

OBJECTIVES: To evaluate the effectiveness and safety of ICSI relative to c-IVF in couples with males presenting with normal total sperm count and motility.

SEARCH METHODS: We searched the following databases and trial registers: Cochrane Central Register of Controlled Trials (CENTRAL), Embase (excerpta Medica Database), MEDLINE (Medical Literature Analysis and Retrieval System Online) and PsycINFO (Psychological literature database) for articles between January 2010 and 22 February 2023.

SELECTION CRITERIA: We included randomised controlled trials (RCTs) that compared ICSI with c-IVF in couples with males presenting with normal total sperm count and motility.

DATA COLLECTION AND ANALYSIS: We used standard methodical procedures recommended by Cochrane. The primary review outcomes were live birth and adverse events. Secondary outcomes included clinical pregnancy, viable intrauterine pregnancy and miscarriage.

MAIN RESULTS: The original review published in 2003 included one RCT. In this 2023 update, we identified an additional two RCTs totalling a cohort of 1539 couples, comparing ICSI with c-IVF techniques. Two studies reported on live birth. Using the GRADE method, we assessed the certainty of evidence and reported evidence as low-certainty for live birth. We are uncertain of the effect of ICSI versus c-IVF for live birth rates (risk ratio (RR) 1.11, 95% confidence interval (CI 0.94 to 1.30, I 2 = 0%, 2 studies, n = 1124, low-certainty evidence). The evidence suggests that if the chance of live birth following c-IVF is assumed to be 32%, the chance of live birth with ICSI would be between 30% and 41%. For adverse events; multiple pregnancy, ectopic pregnancy, pre-eclampsia and prematurity, there was probably little or no difference between the two techniques. No study reported the primary outcome stillbirth. For secondary outcomes, we are uncertain of the effect of ICSI versus c-IVF for clinical pregnancy rates (RR 1.00, 95% CI 0.88 to 1.13, I 2 = 45%, 3 studies, n = 1539, low-certainty evidence). Comparison of viable intrauterine pregnancy rates showed probably little or no difference between ICSI and c-IVF (RR 1.00, 95% CI 0.86 to 1.16, I 2=75%, 2 studies, n = 1479 couples, moderate-certainty evidence). The high heterogeneity may have been caused by one older study conducted when protocols were less rigorous. The evidence suggests that if the chance of viable intrauterine pregnancy following c-IVF is assumed to be 33%, the chance of viable intrauterine pregnancy with ICSI would be between 28% and 38%. Miscarriage rates also showed probably little or no difference between the two techniques.

AUTHORS' CONCLUSIONS: The current available studies that compare ICSI and c-IVF in couples with males presenting with normal total sperm count and motility, show neither method was superior to the other, in achieving live birth, adverse events (multiple pregnancy, ectopic pregnancy, pre-eclampsia and prematurity), also alongside secondary outcomes, clinical pregnancy, viable intrauterine pregnancy or miscarriage.