A woman normally produces one egg during each menstrual cycle. However, IVF requires multiple eggs. Using multiple eggs increases the chances of developing a viable embryo. You’ll receive fertility drugs to increase the number of eggs your body produces. During this time, your doctor will perform regular blood tests and ultrasounds to monitor the production of eggs and to let your doctor know when to retrieve them.

"Demographers tend to define infertility as childlessness in a population of women of reproductive age," whereas "the epidemiological definition refers to "trying for" or "time to" a pregnancy, generally in a population of women exposed to" a probability of conception.[8] Currently, female fertility normally peaks at age 24 and diminishes after 30, with pregnancy occurring rarely after age 50.[9] A female is most fertile within 24 hours of ovulation.[9] Male fertility peaks usually at age 25 and declines after age 40.[9] The time needed to pass (during which the couple tries to conceive) for that couple to be diagnosed with infertility differs between different jurisdictions. Existing definitions of infertility lack uniformity, rendering comparisons in prevalence between countries or over time problematic. Therefore, data estimating the prevalence of infertility cited by various sources differs significantly.[8] A couple that tries unsuccessfully to have a child after a certain period of time (often a short period, but definitions vary) is sometimes said to be subfertile, meaning less fertile than a typical couple. Both infertility and subfertility are defined as the inability to conceive after a certain period of time (the length of which vary), so often the two terms overlap.
Repeated failed rounds of IVF can help identify causes of infertility. For example, if sperm and egg quality are normal, then the conception issue may be rooted at the embryonic or implantation level. In other words, if IVF fails to result in pregnancy despite successful fertilization, embryonic development or implantation may be to blame. Still this is a very expensive way to start getting answers.