Final answer:
Diaphoresis and dizziness in a pregnant woman lying in the dorsal recumbent position can be attributed to supine hypotensive syndrome. It is caused by the compression of the inferior vena cava by the pregnant uterus, leading to reduced blood return to the heart and lower blood pressure.
Step-by-step explanation:
The cause of diaphoresis (excessive sweating) and dizziness when a pregnant woman is in the dorsal recumbent position is often supine hypotensive syndrome. This condition occurs when the pregnant uterus compresses the inferior vena cava, reducing the return of blood to the heart and subsequently decreasing cardiac output. This can lead to a drop in blood pressure and symptoms such as dizziness and sweating. Dehydration, gestational diabetes, and uterine contractions are less likely to be the direct cause of these symptoms specifically related to the woman's position.
During pregnancy, changes like increased respiratory minute volume and pelvic elasticity in the later stages can affect a woman's experience of breathlessness and giddiness. However, when diaphoresis and dizziness occur in the dorsal recumbent position, they are generally associated with the physiological changes brought on by the pressure of the uterus on major blood vessels.