variable deceleration vs early ones

[tsm007]

I'm working on trying to learn the basics of FHM and have been trying to work through this site's tutorial and get to this quiz Fetal Heart Tracing Quiz 2 and trying to figure out why these are variable decels and not early ones? They line up with the contractions. Is there something else I am missing? Do variables often line up with contractions like this?

[klone, MSN, RN]

Look at quiz #4 for the difference between a variable decel and an early. Early decels are generally shallow. They look sort of like a late, except they mirror the timing of the contraction.

Great site, btw! Thanks for that - I'm studying for my RNC-OB exam and this is very helpful.

[klone, MSN, RN]

Or, as I was taught - early decels are generally spoon-shaped, whereas variables don't really have a regular pattern, and look more jagged. If any experts can correct me, I would welcome it! It's been 3 year since I've worked as a bedside L&D nurse.

Okay, editing to add (sorry to serial post, but I'm learning here too, can't believe how much I've forgotten!).

An early decel is defined as happening at the same time as the contraction. The nadir happens at the same time as the peak of the contraction, and it goes back to baseline at the same time as the end of the contraction. Basically, it completely mirrors the contraction (although it might not go as deep as the contraction goes high).

A variable is a rapid decrease, with onset to nadir being less than 30 seconds. Usually you'll see it dip very abruptly, rather than gradually.

Standardized Nomenclature for Electronic Fetal Monitoring

[NurseNora, BSN, RN]

The difference is that 30 seconds mentioned by the previous poster. A variable deceleration varies in shape, timing, length and depth. The main way of identifying a variable is by how long it takes to reach the deepest point. The mechanism of variables is a vagal response to cord compression. They may occur with contractions that put pressure on the cord, or randomly: the baby moves into a position that puts pressure on the cord. Variable decelerations are the ones seen most commonly.

[tsm007]

Thank you both so much! I think I get it now. You both were very helpful!

[Elvish, BSN, DNP, RN, NP]

If there are variables that deep and long I'm hoping Mom is about to deliver!!!!

But yes....given the rapid drop from onset to nadir I'd call them variables as well, regardless of where they are placed WRT contractions.

[cayenne06, MSN, CNM]

WOW! What a great site.

The defining characteristic in this strip is the abrupt descent/return to baseline. The relatively low nadir is another clue. Earlies are generally shallow, and the descent/return to baseline is more gradual.

That being said, in "real life," you often have decels that don't play by the book. It is quite common to have decels that seem to elude easy categorization. It's important to know the phys/pathophys so you can implement appropriate intereventions, even when you arent 100% sure about what you are dealing with.