7 - Techniques for IVF

Summary

Much recent research in IVF treatment has concentrated on ovarian stimulation drugs, regimens, improving the laboratory techniques of oocyte fertilization and embryo culture. However, efficient and effective oocyte recovery and embryo transfer techniques may have been neglected. This is unfortunate, as efforts to maximize ovarian stimulation and the work of embryologists in producing high quality embryos and blastocysts may be squandered if suboptimal oocyte retrieval and embryo transfer techniques are used. In this chapter we describe an evidence-based approach to oocyte retrieval and embryo transfer and briefly review the ongoing debate on the number of embryos transferred.

Oocyte retrieval

The early years of IVF were characterized by laparoscopic oocyte retrieval from unstimulated ovaries during the natural menstrual cycle. The disadvantages of laparoscopic oocyte retrieval include the need for general anaesthesia, the small but finite risk of damage to abdominal organs and blood vessels, and the greater overall cost and inconvenience to the patient of an IVF treatment cycle. Since most women will require repeated IVF treatment cycles, laparoscopy is not satisfactory as a routine method of oocyte retrieval.

By the early 1980s ultrasound technology had developed to such an extent that the first cases of transvesical oocyte recovery under transabdominal ultrasound guidance were reported (Lenz et al., 1981). This was a major advance over the laparoscopic approach. By the late 1980s the development of high frequency vaginal probe ultrasound transducers allowed direct transvaginal ultrasound directed oocyte retrieval (TUDOR). A number of randomized trials testify to the advantages of this method over alternative approaches and TUDOR remains the method of choice (Tan et al., 1990).

Recently, follicular aspiration under three-dimensional ultrasound control has been reported (Feichtinger, 1998).