Does parasympathetic blockade alter fetal heart rate variability between decelerations during brief repeated umbilical cord occlusions in fetal sheep?
The parasympathetic nervous system is the key mediator of fetal heart rate variability between decelerations during labor-like repeated hypoxemia.
< 0.01), and abolished FHRV on visual inspection compared with the control group. Tachycardia in the atropine and vagotomy groups resolved over the first 10 min after the final UCO, in association with evidence that the SNS contribution to FHRV progressively returned during this time. Our findings support that SNS control of FHRV is acutely suppressed for at least 4 min after a deep intrapartum deceleration and takes 5-10 min to recover. The parasympathetic system is therefore likely to be the key mediator of FHRV once frequent FHR decelerations are established during labor.
Lear et al. (2020) studied this question.