Fetal Doppler

Specialties Ob/Gyn

Published

Specializes in Emergency.

I am an ED nurse and had a question for ya'll. Is it possible for the babies heart to beat in sync with the mom? At nine weeks I heard the swishing of the femoral pulse at about 75 bpm, then moved over toward where the uterus should be and heard the same swishing followed by a second swish--at a rate of 150, however, the first swish was in sync with the mom's pulse rate? So, if that was the mom, then what the heck was the second beat, it would have to be the baby right? But how could the babies heart beat in sync perfectly with the mom's?

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Specializes in Specializes in L/D, newborn, GYN, LTC, Dialysis.

I have never seen that. What I do in OB is to attach mom to pulse oximeter and monitor the fetal heart rate simultaneously. You will see the differences very soon.

Esp at 9 weeks, fetal heart rates are extraordinarily fast. Usually well over 150-160 BPM....170 or even 180 not uncommon.

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Sounds like you were hearing some sort of maternal circulation. (Not sure what the "second beat" you heard was) I haven't ever heard of mom and baby beating together. If I'm unsure what I'm hearing with a doppler, I palpate Mom's peripheral pulse at the same time. If what you're hearing with the doppler coordinates with what you're feeling then keep looking.icon7.gif

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I would not try and listen to fatal heart at nine weeks it is far too difficult and what would be achieved if you could not heard it -it would leave everyone very worried as the pregnacy progress and the uterus become a abdominal organ and no longer hiding behind the pelvic bone ascultation of the fetal heart becomes easier.

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Specializes in Emergency.

Another ER nurse here, at what week of gestation do you OB nurses start to doppel heart tones?

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Specializes in Community, OB, Nursery.

In theory you can hear them at about 10 weeks give or take. My OB told me when I was pregnant c DS that there was about a 50/50 chance at that stage. I had already used the doppler where I was working & heard him for myself. (about 180 bpm.) But it took forever to find.

Usually where I am if we have an antepartum, the docs don't even write to check FHTs unless they are above 20 weeks. Even then they are sometimes extremely hard to find. Those babies jump all over the place.

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Specializes in Emergency.

Thank you for the reply. I thought it was 20 weeks.

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Specializes in Specializes in L/D, newborn, GYN, LTC, Dialysis.

I have definately heard fht at 9 weeks. But that is about as early as I have found them.

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Specializes in High Risk In Patient OB/GYN.

Maybe what you heard was moms pulse via abd. aorta, plus the faint "pulse" of the vena cava? At 75bpm (MHR), that would be doubled to 150, so the math adds up perfectly.

When checking FHR, you should always check moms to make sure that you're just not hearing a double MHR (or hearing a tachy mom in 120s-130s, etc).

We don't check here (antepartum) until about 12-16 weeks, depending on MD. Then it's FHR qday, until about 20-22 weeks, then it's qshift, then at around 26-28weeks it's FHR qshift, NST qday.

I agree that checking at 9 weeks is almost a sure shot way to scare everyone and create more of a problem than a solution. If there is a concern about the embryo being alive still, then a sono is performed to visualize the heart beat.

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Specializes in ER.

In the ER I don't check unless I think the doc will do something about it if I don't find them. At about 12 weeks I might try, but not 10 unless I explained to the parents that not finding the heartbeat doesn't mean a whole lot at that gestation and with our low tech equipment.

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