What maternal activity can commonly stimulate sinus tachycardia in neonates?

Crying is a common maternal activity that can stimulate sinus tachycardia in neonates due to its association with increased maternal stress levels. When a mother cries, it often elevates her heart rate, and this physiological response can have a direct influence on the fetus, especially in the late stages of pregnancy. The stress hormones released during crying can also stimulate the fetal sympathetic nervous system, leading to an increase in fetal heart rate and potentially resulting in sinus tachycardia in the neonate after birth.

In contrast, being still, sleeping, and feeding do not typically evoke the same stress-related response. Being still and sleeping are generally associated with a calm and stable environment, leading to decreased physiological stimulation for the fetus. While feeding can stimulate the neonate's metabolism, it doesn't generally produce the acute stress response seen in crying, which is more impactful in terms of heart rate elevation.