What are some potential causes of fetal tachycardia?

Fetal tachycardia is defined as a fetal heart rate greater than 160 beats per minute and can be influenced by various factors. One of the significant causes of fetal tachycardia is infection, particularly chorioamnionitis, which is an infection of the membranes surrounding the fetus. Infections can lead to an increased metabolic demand on the fetus, resulting in an elevated heart rate.

Drugs, including stimulants or certain medications administered to the mother during labor, can also contribute to fetal tachycardia. Stimulants can increase the fetal heart rate by enhancing the sympathetic nervous system or directly affecting fetal heart tissue.

The interaction of these two factors—infection and drug exposure—can significantly elevate fetal heart rate, making option B a correct choice.

It is important to understand that while other factors, such as maternal hypertension or certain lifestyle choices like caffeine consumption, can affect fetal heart rate, they may not be as directly correlated with tachycardia as infection and drug exposure. This distinction helps to clarify why option B is the most relevant choice among the provided options.