Which of the following is NOT a typical contributor to fetal tachycardia?

• A. The mother receiving terbutaline (Brethine)
• B. The mother receiving ritodrine (Yutopar)
• C. Maternal fever or infection
• D. Maternal hypotension

Answer: (D)

Fetal tachycardia comes from factors that raise fetal heart rate, either through direct stimulation of the fetal heart or through increased fetal metabolic demand. Beta-adrenergic tocolytics given to stop preterm labor, such as terbutaline and ritodrine, cross the placenta and stimulate fetal beta receptors, which speeds up the heart. Maternal fever or infection also raises fetal metabolic needs and triggers a faster fetal heart rate. In contrast, maternal hypotension lowers placental blood flow, which tends to cause fetal distress characterized by decreased oxygen delivery and patterns like bradycardia rather than a consistently elevated heart rate. So the scenario that does not typically lead to fetal tachycardia is maternal hypotension.