A US study has found that despite increased use of intracytoplasmic sperm injection (ICSI) over recent years, the technique is not associated with
any improved reproductive outcomes over conventional IVF.
The findings, published in JAMA, also indicated that ICSI
might even have a detrimental effect in cases without male infertility.
ICSI is an adaptation of IVF, introduced in 1992, in which a single sperm is
injected directly into the egg, which was developed primarily for use in cases of male infertility, such as low sperm count or poor sperm motility.
Using data from the US National Assisted Reproductive
Technology Surveillance System, the researchers found that between 1996
and 2012, the incidence of ICSI during fresh IVF cycles more than doubled from
36.4 percent to 76.2 percent. The greatest increase was in cycles with no male infertility where ICSI use rose from 15.4 to 66.9 percent .
Using data for the 2008 to 2012 period, the researchers indirectly estimated fertilisation rates by looking at the number of cycles cancelled following oocyte retrieval. This indicated that, when male infertility was present, ICSI led to an increased likelihood of fertilisation compared with conventional IVF. But they also found that the
reproductive outcomes - including
pregnancy, miscarriage and live birth - of traditional IVF and IVF using
ICSI were similar in cycles with male factor infertility.
Furthermore, in cycles without male factor infertility, the
use of ICSI resulted in 'small but significant' reductions in implantation,
pregnancy, live birth, multiple live birth and low birth weight rates compared
with conventional IVF.
The researchers from the Centers for Disease Control and Prevention in Atlanta comment: 'Although such differences may
be a function of the large sample size and thus not clinically relevant, our
findings suggest that use of ICSI may improve fertilisation rates but not
implantation or pregnancy rates in the setting of unexplained infertility,
advanced maternal age, and low oocyte yield.'