Young men conceived by ICSI have lower sperm quality, finds studyBMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i5415 (Published 06 October 2016) Cite this as: BMJ 2016;355:i5415
Young men conceived by intracytoplasmic sperm injection (ICSI) have significantly lower sperm concentrations, reduced total sperm counts, and fewer motile sperm than men of the same age who were conceived without fertility treatment, first results from the oldest cohort of ICSI offspring have shown.
The introduction of ICSI in 1991 was a major breakthrough for the treatment of male infertility, and latest figures show that more than 2.5 million babies have been born using this technique. The general health of children conceived by ICSI and in vitro fertilisation has been studied extensively, but their reproductive health has not previously been investigated.
Researchers analysed single semen samples provided by 54 young men aged 18-22 who were conceived using ICSI because of severe male factor infertility in their fathers.1 The young men had all been taking part in a Belgian prospective follow-up study since their birth.
Results, reported in Human Reproduction, showed that the young men conceived by ICSI had a lower median sperm concentration (17.7 million/mL of semen) than matched controls conceived spontaneously (37.0 million/mL, P=0.004). They also had lower median total sperm count (31.9 million versus 86.8 million, P=0.001) and lower median total motile sperm count (12.7 million versus 38.6 million, P=0.002).
After adjusting for confounding variables, including age and body mass index, the results showed that young men conceived spontaneously had sperm concentrations almost twice as high as those born after ICSI (odds ratio 1.9, 95% CI 1.1 to 3.2). Their total sperm counts (2.3, 1.3 to 4.1) and total motile sperm counts (2.1, 1.2 to 3.6) were also twice as high.
Those conceived by ICSI were nearly three times more likely to have sperm concentrations below 15 million/mL of semen, which is the World Health Organization’s definition of normal, and four times more likely to have total sperm counts below 39 million.
“These findings are not unexpected,” said study co-author André Van Steirteghem, who pioneered ICSI at the Vrije Universiteit Brussel in Belgium. He explained, “Before ICSI was carried out, prospective parents were informed that it may well be that their sons may have impaired sperm and semen like their fathers.”
The researchers said that the study findings should be interpreted taking into account that ICSI was performed because of impaired spermatogenesis in the offspring’s fathers and should not be generalised to the increasingly common situation where ICSI is carried out even when there is no evidence of male infertility.