The first step towards an “in vitro” fertilisation (IVF) is to extract the oocytes vaginally by means of an ovarian puncture, with the woman sedated. The oocytes are then fertilised in the lab with the male sperm.
Between 16 and 18 hours later, the oocytes are checked to see if they have been fertilised and the couple is informed of the results. After 48 hours, the fertilised oocytes are examined to confirm that they have divided and the intrauterine transfer of the embryos is performed. A maximum number of 3 embryos are transferred per procedure, to reduce the risk of a multiple pregnancy. If more than 3 good quality embryos have been obtained, the remaining can be cryopreserved, so they can be transferred in another cycle, should this one not succeed, or if a second child is sought. The pregnancy rates with an IVF cycle are between 35 and 45%.
Intracytoplasmic Sperm Injection (ICSI) involves the introduction of a single sperm into each of the oocytes, hence overcoming an additional barrier. For the female patient, the process is identical to the “In Vitro” Fertilisation mentioned earlier. The only difference is the high level of specialisation and skill required by the lab. Sperm injection was originally employed for severe male problems, such as small sperm concentration or even absence of sperm in the ejaculate, requiring the sperm to be collected directly from the testicle. It is also used when conventional In Vitro Fertilisation fails.
Nowadays this technique is more widely used, because the fertilisation rates are higher than for classic IVF and hence couples are more likely to be successful. Currently, the pregnancy rates after an ICSI are 50-55%.