In Vitro Maturation
and Ova Freezing
Scientists have been studying the physiology and cell processes of human ova (eggs) since the 1920s; however, it was not until 1938 that the first successful in vitro maturation studies were performed with human ova. During the early 1930s scientists discovered that mature ova were most likely to be found in women between the twelfth and fifteenth days of the menstrual cycle. By the mid-1930s they had discovered that the maturation of these ova occurs within the follicle prior to ovulation. By 1939 it had been observed that fully grown, follicle-free ova mature spontaneously if placed in a culture. This was an important breakthrough because it meant that scientists were no longer dependent on mature ova formed in vivo (in the body). It was now possible to produce mature ova from the much larger pool of immature ova.
Following this discovery the focus then moved from using the less accessible ova matured in vivo to using in vitro-matured human ova. A new phase of research thus began in which scientists attempted to achieve successful fertilization in a culture medium. During the 1950s further work was undertaken on the fertilization status of ova to obtain a better understanding of human follicular ova before and after exposure to sperm in vitro. In the 1960s Robert Edwards and Patrick Steptoe (the same scientists who in 1978 managed the first IVF baby) documented for the first time the stages of maturation in the nucleus of human ova. This research was then used as the foundation for other studies to improve the