Vanishing twin syndrome Vanishing twin syndrome is defined as the spontaneous reduction of a fetus while still in utero ((The vanishing twin: a major determinant

What is vasa previa Vasa previa is a rare but clinically important obstetrical complication in which fetal blood vessels run in close proximity to the

Valsalva maneuver Valsalva maneuver, also known as Valsalva-Weber maneuver, is a forced expiratory effort against a closed airway (with mouth and nose closed) with the

What is vasodilation Vasodilation is the widening of blood vessels or an increase in blood vessel diameter. Vasodilation increases blood flow in the body to

What is a hymen Hymen is a very thin piece of skin-like tissue with a small, circular opening in the center that partly covers the

Urachus Urachus is a tube-like structure that connects the umbilical cord (belly button) to the urinary bladder that is present before birth, which goes away

What is upper motor neuron Upper motor neurons originate in the gray matter of the brain and send long axons which carry the impulses for

What is uterine rupture Uterine rupture is a rare but very dangerous complication in which your uterus tears open along the scar line from a

Urinary urgency Urinary urgency is a symptom of the inability to postpone urination once the sudden, strong need to urinate has been felt. This causes

Tumor suppressor genes Tumor suppressor genes are normal genes that slow down cell division, repair DNA mistakes or tell cells when to die (a process