Table 1. Proposed (British) Definitions of FHR Decelerations.

Early decelerations	Recurrent/repetitive slowing of FHR (depth > 15 beats/min) with onset early in the contraction and return to baseline at the end of contraction.
Late decelerations	Recurrent/repetitive slowing of FHR with onset mid to end of contraction and nadir more than 20 s after peak of contraction and ending after the contraction. If baseline variability is less than 5 beats/min, then the definition would include decelerations less than 15 beats/min.
Variable decelerations	Recurrent/repetitive slowing of FHR with varying time relationship to the contraction cycle. They tend to markedly vary in shape. (Variable decelerations could be further classed as abnormal or complicated (the term atypical is now tainted) if more than 50% of them have late components, but this has to be interpreted in the clinical context.)

These definitions are very similar to the traditional British practice between 1970 and 2007 [14-17] and of Edward Hon [21].