A frequent cause of infertility is a lack of ovulation or eggs. Controlled ovarian hyperstimulation (COH), can induce the ovaries to produce eggs under ultrasound monitoring. Ovarian stimulation can be achieved with either pills (clomid, letrazole) or injectable medications (follistim, gonal-F.)
During a normal menstrual cycle (period), only one or two eggs progress to maturity. In an effort to increase the chances for a pregnancy with In Vitro Fertilization (IVF) or Intrauterine Insemination (IUI), it is necessary to stimulate multiple eggs to develop. This increases the number of oocytes (eggs) available for ovulation, fertilization and implantation.
Maturity and retrieval of an oocyte (egg) is guided by the number, size and growth of follicles along with the production of Estradiol, the primary hormone produced by a healthy egg. The follicle is a small fluid-filled structure located in the ovary which contains the oocyte. The amount of fluid in the follicle increases as the egg matures, thereby increasing the size of the follicle. This growth can easily be observed and measured by ultrasound. The measurement of Estradiol and Progesterone in the blood also determine maturity of the eggs and the timing of the retrieval. This is why your blood is frequently drawn during your treatment.