UNEXPLAINED INFERTILITY 
When  couple  have undergone all appropriate tests and no cause for their infertility is found, they are diagnosed as  unexplained infertility.

About 15 percent of infertile couples are diagnosed with unexplained infertility, also referred to as idiopathic infertility.

Unexplained infertility most likely involves issues with poor egg or sperm quality, or problems with the uterus or fallopian tubes that aren’t identifiable during normal fertility testing.

Likely treatments for unexplained infertility that are often successful include:
Fertility drugs with intrauterine insemination (IUI)
In vitro fertilization (IVF)
Ovarian stimulation
Timed intercourse
Lifestyle changes.