Which of the following can cause fetal heart rate variability?

Fetal heart rate variability is influenced by several factors that reflect the well-being of the fetus and its interaction with the uterine environment. The correct answer indicates that both uterine contractions and fetal movement can lead to variations in the fetal heart rate.

Uterine contractions can impact blood flow to the fetus, causing temporary changes in the heart rate as the fetus responds to the varying levels of oxygen and nutrient supply during these contractions. Additionally, fetal movement is a sign of an active and healthy fetus; it can stimulate changes in heart rate as the fetus reacts to positioning and movements within the uterus. These factors contribute to the dynamic nature of fetal heart rate patterns, indicating a responsive and well-functioning fetal nervous system.

The other options would not be as significant in affecting variability in fetal heart rate. While medications taken by the mother can influence the fetal heart rate, they do not inherently create variability in the same manner as contractions or movements. Fetal anomalies may lead to more consistent patterns rather than variability, and maternal age plays a more indirect role, influencing fetal health overall but not directly causing heart rate variability.