These two terms are very frequently mentioned during each one of your visits to the fertility clinic. Both of them imply different techniques using the same gametes, sperm and egg.
ICSI stands for Intra Cytoplasmic Sperm Injection. This is a technique, which takes one sperm inside a needle, and the sperm is then injected into the egg.
IVF stands for the In Vitro Fertilization technique, which is the placement of a sperm sample on a dish containing one or more eggs. This way the sperm will naturally penetrate de egg.
Both techniques are complex and require to be performed in an embryology laboratory.
Doctors usually have different criteria to decide if a patient goes to ICSI or IVF. Some of the criteria to do ICSI are:
Poor quality sperm. This can be shown either in the quantity, motility or morphology.
Patients over 40 years old
Prior IVF failures
Borderline sperm DNA fragmentation
Criteria to consider IVF:
Good quality sperm. This has to be shown at least in all of the criteria of motility, quantity, and morphology.
Patients under 40 years old
Sperm DNA fragmentation under 25%
Your fertility specialist will let you know about the results of the analysis and the criteria you have to either undergo ICSI or IVF.
Sometimes a split case of IVF/ICSI can be performed, and in most cases where the sperm quality is borderline, or there is unexplained infertility there is a good chance of success. A study shows that performing ICSI on at least some of the oocytes will avoid unnecessary fertilization failure in patients with borderline semen (1)(2).
Several serious studies have not shown any difference on embryo quality obtained with ICSI or FIV. Some of them concluded: embryo quality does not seem to be influenced by the mode of fertilization (IVF or ICSI) (3).
Another important fact is that live birth depends mostly on embryo quality than the method used for fertilization (4).
Some reproductive centers prefer to do 100% ICSI because the fertilization rates can be higher than using conventional IVF.
The conclusion is that the criteria to decide whether to use conventional IVF or ICSI should be discuss and considered to evaluate the true fertilization capability of the patients.
Conventional in vitro fertilization versus intracytoplasmic sperm injection in patients with borderline semen: a randomized study using sibling oocytes. Van Der Westerlaken, Naaktgenoren N. Fertil Steril. 2006 Feb;85(2):395-400.
Fertilization of IVF/ICSI using sibling oocytes from couples with subfertile male or unexplained infertility. Li Z, Lin H, Xiao W. J Juazhong Univ Sci Technolog Med Sci. 2004;24(4):365-8,384.
Comparison of embryo quality between intracytoplasmic sperm injection and in vitro fertilization in sibling oocytes. R.Yoeli, R. Ovieto, J. Ashkenazi. J Assisted Reprod Genet. 2008 Jan;25(1):23-28.
Pregnancy outcome and live birth after IVF and ICSI according to embryo quality. Patricia Fauque, Roger Leandri, Francoise Merlet. J Assisted Reprod Gent. 2007 May;24(5):159-165.