The Natural Cycle for In Vitro Fertilization

Abstract

Although the first in vitro fertilization (IVF) success occurred using natural cycles, the majority of IVF centers around the world favor the use of ovulation-inducing medications prior to oocyte retrieval. The concept of using ovulation-inducing medications for IVF evolved for a number of reasons. When the procedure was being developed, a laparotomy was required to retrieve oocytes. Laparoscopy replaced laparotomy as the method of choice for oocyte retrieval unless extensive adhesions made laparoscopy unsuitable. In addition, embryo culture techniques were less good, ultrasound had poorer resolution, and the detection of ovulation was less precise. For all of these reasons, the initial results using the natural cycle were poor and a tendency to use medication evolved. An increasingly large number of ovulation-inducing drugs are now being used individually or in combination for IVF. The primary goal of all medicated cycles is to increase the number of available oocytes for fertilization and transfer.