Today we delve into somewhat denser topics. A case of abrupt FHR baseline change.

SUMMARY OF WHAT WAS DISCUSSED:

1. This fetus arrived healthy in the delivery room.
2. What could have caused the FHR baseline to increase from 140 to 200?
   1. Hypoxia? Not without prior decelerations.
   2. Infection? Not up to 200.
   3. Dehydration? It does not cause that much fetal tachycardia.
   4. Drugs? None had been administered.
   5. Conduction disorders –> This is what we need to suspect.
3. We have spoken especially about supraventricular arrhythmias and re-entry circuits. And the risk they cause in the fetus of heart failure.
4. We have discussed the management in detail, differentiating three scenarios:
   1. Antenatal period –> A cordocentesis can be attempted, and Flecainide administered if you have a strong perinatal medicine service available.
   2. Dilated labor >4cm –> You can try pressing on the anterior fontanelle, which has great parasympathetic irrigation, and stimulate the vagus nerve. It often reverses (it would be like pressing on the carotids in an adult).
   3. Less dilation –> Cesarean section because you cannot know when it will spontaneously revert or how much time the fetus has left.

–> In this case, a cesarean section was performed, and a newborn was obtained with APGAR scores of 9/10/10 and normal pH.