Which of the following can be a sign of progressive uterine hemorrhage in a pregnant woman?

The indication that changing fetal heart rate can be a sign of progressive uterine hemorrhage is rooted in the relationship between maternal blood volume and fetal well-being. When a pregnant woman experiences significant uterine hemorrhage, the supply of oxygen and nutrients to the fetus may become compromised due to decreased maternal blood volume and perfusion.

As the situation progresses, the fetus may respond to this reduced blood flow with alterations in its heart rate. Typically, a decline or variability in fetal heart rate reflects fetal distress, which can be associated with conditions such as hypoxia due to inadequate blood flow. Therefore, monitoring fetal heart rate can serve as a critical assessment tool in identifying maternal bleeding, allowing for timely intervention to protect both the mother and the baby.

In contrast, other signs such as severe headache, severe abdominal pain, and increased blood pressure may not directly correlate with hemorrhage during pregnancy. While they can indicate a range of complications, they are not as specifically related to the fetal response to uterine bleeding as changes in fetal heart rate are. Understanding the direct and immediate impacts on the fetus makes the changing fetal heart rate the most significant sign of progressive uterine hemorrhage among the options presented.