Ultrasound (US)
Use of high-frequency sound waves for creating an image of internal body parts.

Unexplained (Idiopathic) Infertility
Infertility for which no cause has been determined despite a comprehensive evaluation.

Ureaplasma
A microorganism similar to mycoplasma.

Urethra
The tube through which urine from the bladder is expelled.

Urologist
A physician who specializes in the surgical treatment of disorders of the urinary tract and male reproductive tract.

Uterus
The womb; female reproductive organ that nourishes the fetus until birth.