The increasing survival rates of cancer patients [1] have encouraged many specialists to focus on the irreversible consequences of chemotherapy and radiotherapy. Chemotherapy and radiotherapy treatment for cancer or other pathologies have resulted in improved survival rates, but these treatments may also lead to sterility [2]. The increasing success of oncological treatments means it is now even more crucial to implement procedures aimed at preserving fertility.

Similar to cancer patients, there are some non-oncological conditions currently treated with gonadotoxic agents, such as patients with autoimmune disorders or some chromosomal abnormalities that can lead to ovarian failure. There are also other situations where a woman may benefit from fertility preservation procedures, such as women with severe or recurrent endometriosis or women who electively postpone conception [3].

Survival rates after cancer have increased significantly in recent decades; however, these treatments also have drawbacks, and patients (or parents in the case of children) must be informed of the long-term side effects of oncological treatments and the possible options for preserving the fertility of these patients. It is important to set out clearly the possible risks of developing ovarian failure or azoospermia with oncological treatments. These will depend on the age of the patients and on the type, dose and duration of chemotherapy, and on the field, dose and duration of radiotherapy.

Despite the various advances and the increasing success rates of assisted conception treatment, implantation continues to be a rate limiting step. For implantation to occur a blastocyst must attach to and invade the endometrium and as such both the embryo and endometrium are considered critical to the process of implantation. However, there are other factors to consider. Many conditions of the uterine cavity may influence the ability of the embryo to implant such as uterine submucosal fibroids and endometrial polyps, which are well recognized to exert an adverse effect. In addition, an embryo’s implantation potential may be affected by sperm and oocyte quality. Iatrogenic factors such as laboratory conditions and embryo transfer technique play an important role in successful implantation, hence this chapter will focus on the embryo transfer procedure. This is the final step in the treatment cycle, the culmination of both clinicians’ and embryologists’ efforts and a day of great hope for the patients. The importance of the embryo transfer procedure is not to be underestimated. This chapter will highlight the importance to clinicians of not adopting a “one-size-fits-all” approach when planning embryo transfer. It is incumbent on reproductive medicine specialists to focus on the embryo transfer procedure, try to preempt any potential issues that may adversely affect success rates and adopt an individualized plan for embryo transfer when necessary.