Tubal factor usually means that the woman s fallopian tubes are blocked or damaged, making it difficult for the egg to be fertilized or for an embryo to travel to the uterus. Male factor usually refers to a low sperm count or problems with sperm function that make it difficult for a sperm to fertilize an egg under normal conditions. Endometriosis involves the presence of tissue similar to the uterine lining in abnormal locations. This condition can affect both fertilization of the egg and embryo implantation. Ovulatory dysfunction means that the ovaries are not producing eggs normally or that egg production has diminished with age.
Uterine factor means a disorder of the uterus that results in reduced fertility.
Unexplained cause means that no cause of infertility was found in either the woman or the man. Other causes of infertility include immunological problems, chromosomal abnormalities, cancer chemotherapy, and serious illnesses. Who Had ART Cycles Using Fresh, Nondonor Eggs or Embryos, 1998. Figure 14 shows the percentage of live births after an ART procedure according to the primary cause of infertility. However, the use of these diagnostic categories may vary from clinic to clinic, and the definitions are imprecise.