Question about fetal heart beat

Specialties Ob/Gyn

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Hi, I'm working on some questions for a homework assignment and I'm stuck on one. The question is about a woman who has been trying to get pregnant and after having some spotting, she went to the clinical and found out that her cervix is closed and her uterus is about 6-8 weeks in size. She has a positive Chadwick's sign but no fetal heart tones can be located on the Doppler. There's also a small amount of dark blood at the cervical os. The question is asking about the importance of fetal heart tones not being heard.

I first was thinking that it was too early for the Doppler to pick up on a heartbeat, since in my book it says that it is usually done between 8 and 12 weeks. But then after thinking some more about it I also am thinking it could be a missed abortion since the cervical os is closed.

Any clarification is very appreciated!

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

If the cervix is closed I would think that is a good sign and you can't always hear FHT with a doppler at 6-8 weeks. Thread moved for best respnse because OB is not my forte.

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Specializes in OB-Gyn/Primary Care/Ambulatory Leadership.

Esme is correct. We wouldn't be able to hear FHTs via Doppler at 6-8 weeks. With a woman who is having spotting, we would do a translady partsl U/S to make sure the pregnancy is intrauterine, and at that gestational age, we should be able to get a crown-rump length and visualize cardiac activity. If we can't visualize cardiac activity, or if we see a yolk sac with no embryo, we would probably order serial quant hcg levels.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

Thank you OB is SO NOT my comfort zone.

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Specializes in Nurse-Midwife.

What are the pt's dates by LMP? If she is measuring 6-8 weeks, but is closer to 12 weeks by LMP, then this looks more like a miscarriage if no FHTs are heard.

Spotting at this gestation may or may not be associated with miscarriage. Ectopic pregnancy is another consideration - the goal being to catch it before a tubal rupture. I guess there's no way to rule out a molar pregnancy at this point, either.

Ultrasound evaluation would provide more information in this situation.

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Specializes in SICU, trauma, neuro.

Agreed...you wouldn't expect fetal heart tones to be heard w/ a Doppler at 6-8 wks. Also, when during pregnancy is it normal for the cervical os to be open? Typically it happens at the end of pregnancy--mostly during labor, but can start to dilate in the weeks prior (especially if mom is a multip) Or, the cervix will open early in pregnancy if a spontaneous abortion is going to occur or has already occurred. It is possible that she's had a missed abortion, where the embryo is still in there and the os is closed; but a closed os is also a normal finding in the 1st trimester.

In real life, more info would be needed to figure out what's going on. How far along is she really? Does her uterine measurement match up with her LMP? What does the ultrasound show--embryo w/ no heartbeat, no embryo, one much smaller than expected for dates? What are her hcg levels--falling, high but no embryo visible on u/s (now you worry about an ectopic), rising but not quickly enough to suggest a viable pregnancy?

But for the simple question "What does it mean that no fetal heart tones are heard?" I'd have to agree that you almost certainly won't hear them at 6-8 weeks.

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Specializes in Community, OB, Nursery.

When I was pregnant with #2 my OB said the earliest he ever got someone's FHTS with a Doppler was 8+5....and he was the go-to guy for difficult heart tones. Agree with other posters that there could be other factors at play but if the dates are good and the pregnancy is normal, I wouldn't expect to hear FHTs that early.

When we have an antepartum in the hospital before about 12-15 weeks - say, hyperemesis - they never write orders for us to get heart tones because they know it's very hit or miss that early.

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Specializes in OB.

When I get a pt less than 22 weeks I usually don't even bother with the u/s on the fetal monitor and go straight to the Doppler.

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Specializes in MedSurg, PACU, Maternal/Child Health.

We have EFM for FHR only for patients 23 weeks and up. Patients less than 24 weeks have only tocometer part of EFM for 20 minutes and Doppler for FHR. Doppler is for gestation of 12 to 22 weeks. Our patients less than 12 weeks do not get Doppler and are usually admitted for uncontrolled BP or glucose, sickle cell, asthma attack, or for an infection (kidney, UTI, etc) or virus. But we still have them on our floor bc they are pregnant and so we do med-surg type treatment for them.

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