In cases of mild preeclampsia, what physiological change is typically observed in the mother?

In cases of mild preeclampsia, elevated blood pressure is a hallmark physiological change observed in the mother. Preeclampsia is characterized primarily by hypertension along with other possible symptoms, such as proteinuria. The elevation of blood pressure typically occurs due to the increased resistance in blood vessels caused by placental dysfunction and the consequent release of factors into the maternal circulation that affect blood vessel tone. Monitoring blood pressure is crucial for the management of preeclampsia, as it can lead to complications for both the mother and fetus if not properly addressed.

The other options do not align with the physiological changes typically associated with mild preeclampsia. Increased heart rate may occur due to various factors but is not a defining characteristic. Decreased urine output is often noted in more severe cases or as a result of complications, whereas lower hematocrit levels are not characteristic of mild preeclampsia, as blood volume expansion typically occurs in pregnancy, which often keeps hematocrit levels in a relatively stable range.