Intracytoplasmic Sperm Injection No Better Than Conventional IVF

Sperm Fertilizing EggFirst introduced in 1992, intracytoplasmic sperm injection (ICSI) doubled between 1996 and 2012 to assist couples struggling with male infertility. Now a new study from researchers at the Centers for Disease Control and Prevention (CDC) concludes that the use of ICSI is no more effective than conventional in vitro fertilization.

ICSI, or intracytoplasmic sperm injection, involves the direct injection of sperm into eggs obtained from in vitro fertilization (IVF). The assisted reproductive therapy is most commonly used with couples who are dealing with male infertility factors such as low sperm counts, poor motility or movement of the sperm, poor sperm quality, sperm that lack the ability to penetrate an egg, and azoospermia.

ICSI is significantly more expensive than traditional IVF. Previous research has also noted a higher risk of transmitted genetic abnormalities with ICSI compared to conventional IVF.

Comment the researchers led by Dr. Sheree L. Boulet of the Division of Reproductive Health at the CDC:

“Pregnancies resulting from the use of ICSI have been associated with 1.5-4 times increased incidences of chromosomal abnormalities, imprinting disorders, autism, intellectual disabilities and birth defects, compared with pregnancies resulting from conventional IVF.”

For the present study, the researchers sought to assess national trends and reproductive outcomes for fresh (non-frozen) IVF cycles following the use of ICSI compared to conventional IVF without ICSI.

Using a retrospective cohort study with data on fresh IVF and ICSI cycles reported to the US National Assisted Reproductive Technology Surveillance System between 1996 and 2012, the researchers identified 1,395,634 fresh IVF cycles, 908,767 (65.1 percent) of which used ICSI and 486,867 (34.9 percent) of which used conventional IVF.

The researchers also identified male factor infertility as a factor in 499,135 (35.8 percent) of the fresh IVF cycles. Other factors such as unexplained infertility, two or more prior ART cycles with prior live birth, low oocyte yield, use of preimplantation genetic testing, and female patients older than age 38 accounted for the remaining 896,499 (64.2 percent) fresh IVF cycles.

According to the study, the use of ICSI doubled between 1996 and 2012 from 36.4 percent to 76.2 percent. ICSI use increased from 76.3 percent in 1996 to 93.3 percent in 2012 for cycles with male factor infertility. ICSI use also increased in cycles without male factor infertility from 15.4 percent in 1996 to 66.9 percent in 2012.

However, among the cycles with male factor infertility, the researchers found outcomes with ICSI similar to the outcomes with conventional IVF. The researchers also identified “small but significant” reductions in implantation, pregnancy, live birth, and multiple live birth in cycles without male factor infertility using ICSI compared to conventional IVF.

In other words, despite an increase in use, intracytoplasmic sperm injection does not appear to improve reproductive outcomes compared with conventional in vitro fertilization.

Comment the researchers on the findings:

“The results of this analysis demonstrate a steady increase in the proportion of ART cycles involving ICSI performed in the US from 1996 through 2012. Compared with conventional IVF, use of ICSI was not associated with improved reproductive outcomes irrespective of male factor infertility diagnosis.”

The researchers do note some limitations of the present study. For example, the US National Assisted Reproductive Technology Surveillance System does not gather information on fertilization rates:

“Although we were able to indirectly assess fertilization failure using the number of cycles canceled following oocyte retrieval, this measure assumes that cycles not proceeding to embryo transfer represent those in which all oocytes failed to fertilize, which may not necessarily be true.”

The study also examined only fresh IVF cycles, although the researchers do not expect the results to differ significantly with frozen embryos.

Two other recent studies found that, although assisted reproductive technology (ART) procedures are associated with low maternal complication risks, ART does increase the risk for serious birth complications including stillbirth, preterm birth, low birth weight, and neonatal death.


Intracytoplasmic Sperm Injection: ICSI:
Intracytoplasmic Sperm Injection No Better Than Conventional IVF, Study Finds:
Trends in Use of and Reproductive Outcomes Associated With Intracytoplasmic Sperm Injection:

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