Variable vs. Late decels


I"m a new L&D nurse...

I have a difficult time telling apart a variable to a late decel.... I know the definition, but when I see it on the strip sometimes it's just so borderline btwn a variable to a late decels... many times I'm worried bc I would think it's a late decels, but when consulting with my fellow RNs, it's a variable to them...

Double-Helix, BSN, RN

Specializes in PICU, Sedation/Radiology, PACU. Has 11 years experience. 1 Article; 3,377 Posts

Look for the trends. Does the heart rate drop consistently after a contraction, or at a few different points throughout the contraction? Also, look at the similarities between decels. Late decels will look fairly uniform- one decel looks almost identical to the next, with a stable heart rate in between. Variable decels change in both duration and severity and seem to occur randomly. If the contractions are coming quickly, it can be hard to tell. Here is a good website about fetal heart rates with strip examples.




862 Posts

You need to read current NICHD terminology. It gives a clear definition of each type of decel as well as how to define the racing in categories. The website the above poster gave is full of great information but it is quite dated as short term and long term variability are no longer used and some other definitions require updating. Here is a summary of the NICHD terms: It is much easier to evaluate the strip when you have the clear definitions in your mind, but always remember than ten people can review the same strip and come up with ten interpretations-- it's proven over and over again to be very inexact.

Variable decelerations are less than 30 seconds from onset to nadir and abrupt in appearance. They may or may not be associated with uterine contractions. They must be at least 15 bpm and last less than 2 minutes. They can occur repetitively with contractions but are still variables if onset to nadir is

Late decels have an onset to nadir > 30 seconds. The nadir of the decel occurs after the peak of the contraction.

There are many "fake" types of decels out there-- "subtle lates" etc. Stick with the definitions and you will be safe.



Specializes in OB/GYN,PHN, Family Planning. Has 20 years experience. 185 Posts

Simply -variables are jagged and more "V" shaped and usually mirror the contraction-not always. Lates will end after the contraction is over. Variables tend to be a cord compression issue and lates a more ominous sign. Try to describe the decel rather than label it. Most importantly what interventions did you do to resolve the decels (move to left/right side, O2, fluid bolus, etc...)