In a nutshell
This study looked at in-vitro fertilization (IVF) outcomes in couples with unexplained infertility. Two egg fertilization techniques were compared: intracytoplasmatic sperm injection versus conventional insemination.
IVF involves the artificial joining of eggs and sperm in a laboratory dish. This is typically achieved spontaneously by putting the two cells together. However, in some cases, the sperm and the egg fail to join and do not produce any viable embryos. In such cases, an alternative method can be used – intracytoplasmatic sperm injection (ICSI). ICSI involves the direct insertion of the sperm into the egg to achieve fertilization. Some IVF centers may fertilize at least some of the eggs using ICSI as this may yield more viable embryos. However, the conventional fertilization technique is believed to lead more often to successful, healthy pregnancies.
Methods & findings
The authors analyzed data from 11 previously published studies with a total of 901 couples undergoing IVF. The mean age of women in these studies was 31. The rate of successful egg fertilization in the laboratory was found to be higher when ICSI was used: 67.5% versus 47.8% with conventional insemination. Fertilization failure was found to be significantly higher when ICSI was not used.
The bottom line
ICSI may lead to more eggs being fertilized during IVF compared to conventional insemination, but further studies are needed to determine major outcomes such as the rates of successful pregnancies, live-births and healthy children.
The fine print
The present analysis was performed using data derived from previously published studies, each of them with different research protocol. The study could not assess pregnancy outcomes due to the conflicting research data and methodology. The authors noted that eggs selected for ICSI are usually better developed and this fact may contribute to the higher fertilization rate. They also highlight the belief that ICSI may increase the risk of congenital abnormalities, although recent studies have failed to show such a link.
Published By :
Fertility and Sterility
Sep 01, 2013