Infertility is a problem that affects approximately 1 in 6 couples at some stage in their lives. After appropriate clinical investigations, the causes of infertility can be related to female factors, male factors, joint male and female factors or remain unexplained. Whatever the cause, the uncertainty to develop a family due to infertility understandably generates stress and anxiety among patients.
Assisted Reproductive Technologies (ART) are widely used to help overcome infertility. Generally known as IVF (In Vitro Fertilization), they include a variety of different methods such as IUI, IVF, ICSI, GIFT, ZIFT, Preimplantation Genetic Screening, assisted hatching, time-lapse monitoring, Endometrial Receptivity Analysis and each are used according to the type of diagnosed infertility.
In traditional IVF, the gametes (egg and sperm cells) are collected and fertilized to form an embryo. Fertilization, and growth for 1 to 5 days, of the embryos happens in an artificial culture medium within the embryology laboratory.
During this time the embryos will develop into a state that allows them to be implanted into the uterine cavity. The embryologist will select the best quality embryos and they will be transferred to the uterus with the objective of implantation.
Limitations of traditional IVF
Traditional IVF is widely used and techniques have progressed considerably, yet it has limitations. According to the European registries generated by the ESHRE, the European Society of Human Reproduction and Embryology in 2011, the clinical pregnancy rate per embryo transfer was 29.1%.¹
Each stage of the IVF process presents challenges due to the interconnection of numerous parameters that cannot be easily optimised and the difficulty to understand and reproduce the physiological conditions.
The culture media remains artificial and it often omits a certain number of components that are naturally present in the uterine cavity. More importantly, embryo development in the laboratory misses all the biological interactions between the embryos and the maternal environment.
In practice the most crucial step is implantation. Ultimately, the success is dependent upon the appropriate coordination of the embryo and the uterus, with the quality of the embryos and the receptivity of the uterus playing a determining role.
Assessment protocols have been developed to qualify embryos on the basis of morphology. However, to date there is no widely accepted technique to assess uterine receptivity.
1) Focus on Reproduction, ESHRE, September 2014