Unexplained infertility is infertility that is idiopathic in the sense that its cause remains unknown even after an infertility work-up, usually including semen analysis in the man and assessment of ovulation and fallopian tubes in the woman. Infertility cases in which the standard infertility testing has not found a cause for the failure to get pregnant. Unexplained infertility is also referred to as idiopathic infertility. Another way to explain it is the "doctors can't figure it out" group.
Polycystic ovary syndrome (PCOS) is the most common hormonal disorder among women of reproductive age. Infertility is one of the most common PCOS symptoms. Because the symptoms of PCOS are seemingly unrelated to one another, the condition is often overlooked and undiagnosed. Polycystic ovary syndrome causes irregular menstrual cycles, excessive body or facial hair and polycystic ovaries as its main symptoms. Polycystic means "many cysts," and PCOS often causes clusters of small, pearl-sized cysts in the ovaries. The cysts are fluid-filled and contain immature eggs. Women with PCOS produce slightly higher amounts of male hormones known as androgens, which contribute to some of the symptoms of the condition.
The cause of PCOS is not known. Some women with PCOS are less sensitive to insulin than other women, a condition known as insulin resistance. Insulin resistance can causes the ovaries to produce too many male hormones. The resulting hormonal imbalance can cause the symptoms of PCOS.