Final answer:
Pregnant women may experience decreased sensations to void due to increased fluid volume from systemic circulation and IV fluids during labor and delivery. The circulatory system changes and micturition reflex is affected by various factors during pregnancy, including physical discomfort and the handling of hypervolemia.
Step-by-step explanation:
Pregnant women have decreased sensations to void as a result of the extra fluid volume returned from the systemic circulation and of IV fluid that may have been received during labor and delivery. During pregnancy, the circulatory system changes significantly, with blood volume increasing by approximately 30 percent, or 1-2 liters, to manage the demands of fetal nourishment and waste removal. The uterus' growth and its pressure on the pelvis can cause venous return issues, leading to frequent urination, which is further exacerbated by increased urine production due to the maternal urinary system processing both maternal and fetal wastes.
Micturition reflex, which is the urge to urinate or void, can be affected during pregnancy. This reflex depends on the interplay of involuntary and voluntary actions by the internal and external urethral sphincters. With an increased blood volume, especially after receiving IV fluids which can contain hypertonic solutions, the urge to void may be decreased due to the body's efforts in managing hypervolemia, which is the retention of water and sodium in the body.
It is also important to note that certain challenges like physical discomfort, secondary dehydration, and neurological conditions can influence micturition. For example, elderly individuals may experience a reduction in their ability to empty their bladders efficiently due to physical or neurological conditions such as Alzheimer's or Parkinson’s disease.