In vitro fertilisation (IVF) – which was originally developed for the treatment of tubal factor infertility – brings female and male gametes into close proximity in a petri dish outside the human body. Major steps in IVF include ovarian stimulation (aiming to stimulate maturation of multiple follicles), oocyte retrieval via transvaginal puncture to obtain multiple oocytes, fertilisation of oocytes and the subsequent development of embryos under strictly controlled circumstances in the laboratory, the transfer of preferably a single, high-quality embryo into the uterine cavity and the freezing of surplus embryos, creating the possibility for additional chances of pregnancy when transferred in subsequent cycles. IVF success rates vary significantly, but current live birth rates are approximately 30 % per started IVF cycle. This represents a cumulative outcome involving the transfer of fresh and frozen embryos harvested from the same oocyte cohort. Intracytoplasmic sperm injection (ICSI) is the mechanical injection of a single sperm into the cytoplasm of an oocyte. This technology is able to generate pregnancies in couples with very poor sperm quality. This sperm may be obtained from ejaculate or, alternatively, epididymal or testicular sperm may be obtained by surgical procedures. Currently, more than 70 % of all IVF cycles worldwide make use of the ICSI procedure. IVF can also be applied in many conditions not related to infertility per se, such as preimplantation genetic testing (PGT) of embryos in families with known monogenic or structural chromosomal rearrangements. Moreover, the preservation of fertility for medical or non-medical reasons by the cryo-storage of ovarian tissue, oocytes or embryos is one of the possibilities created by the IVF techniques. Finally, the use of donor oocytes or embryos, opens up the possibility to become pregnant for those women without oocytes. The transfer of embryos into the uterus of another person, allowing the ‘surrogate mother’ to carry the pregnancy for women without a womb is a possibility due to the IVF technique.
