Boys born to infertile fathers through the means of a common fertility treatment may have lower sperm quantity and quality than those who were spontaneously conceived, a new study has found.
The findings from Universitair Ziekenhuis Brussel (UZ Brussel) in Belgium are based on the first results from the world’s oldest group of young men conceived by means of intracytoplasmic sperm injection (ICSI) fertility treatment.
The study has found that these men, aged between 18 to 22, had almost half the sperm concentration and a two-fold lower total sperm count and total count of motile sperm (sperm that could swim well) than naturally conceived men of similar age.
In addition, compared to men born after spontaneous conception, ICSI men were nearly three times more likely to have sperm concentrations below 15 million per millilitre of semen, which is the World Health Organisation’s (WHO) definition of “normal,” and four times more likely to have total sperm counts below 39 million.
The first ICSI baby was born on 14 January 1992. The current study reports on 54 men, born in the early years of ICSI between 1992-1996, when ICSI was only used to treat male infertility.
ICSI is a procedure by which sperm from the father is injected directly into the mother’s egg in the laboratory, and then the fertilised egg is placed in her womb.
For men who have very few, viable sperm, this means that the fertility experts can choose the best quality sperm and ensure it fertilises the egg by injecting the sperm rather than leaving it to swim to the egg unaided.
Professor Andre Van Steirteghem and his colleagues, who had pioneered ICSI at the Vrije Universiteit Brussel (VUB) in Belgium, knew that the problems that had caused the father’s infertility might be inherited by these men’s offspring.
However questions about the fertility of the ICSI offspring could not be answered because of their young age.
“These findings are not unexpected. 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,” said Van Steirteghem.
“These first results from the oldest group of ICSI-conceived adults worldwide indicate that a degree of ‘sub-fertility’ has, indeed, been passed on to sons of fathers who underwent ICSI because of impaired semen characteristics,” he said.
Since the early days of ICSI, the technique has been used increasingly to treat infertility, even when male infertility is not suspected.
In some countries ICSI is used in nearly 100 per cent of all in vitro fertilisation (IVF) procedures.
Researchers warn that the findings from this study cannot be extrapolated to all offspring born after ICSI since, the technique is increasingly used even when there is no evidence that a couple’s infertility is due to abnormal semen measurements in the man.
The study was published in the journal Human Reproduction.