Comprehensive and Detailed Explanation From Exact Extract–Based NCC C-EFM References:

NCC and AWHONN physiology teachings:

Variable decelerations caused by cord compression lead to:

Transient interruption of umbilical venous flow

Impaired fetal gas exchange

Acute rise in CO₂

Respiratory acidosis (early phase of hypoxemia)

This is well documented:

Early decelerations → head compression → NOT associated with acidemia.

Late decelerations → uteroplacental insufficiency → metabolic acidosis, not respiratory.

Thus:

Variable decelerations → respiratory acidosis

Late decelerations → metabolic acidosis

Correct answer: C. Variable