Questions Regarding Due Date and Fetal Heart Tones

Jane Foley's picture


Dear Ms. Ultrasound,
Hi, I have a couple of questions for you. I am a first time mom to be and alot of this stuff is very confusing to me. My first question is I am wondering how far along pregnant I really am? My last period was on September 17, 2008 and when I went for my first ultrasound on November 6, they told me I was 4 weeks and 3 days pregnant...... So, does that mean I was technically 6 weeks and 3 days pregnant but baby was 4 weeks and 3 days pregnant? When I asked the ultrasound guy if my period date x'd out he said yes. But I am a little confused on that.

My other questions are, I had an appointment for an ultrasound on Tuesday November 18 to see the baby's heart beat and we saw it yay!! But the weird thing is he played it out loud for us and it didn't sound like a baby's heart beat to me. I work in an ER as an RN and I have heard lots of fetal heart tones and it didn't sound to me like a fetal heart tone it sounded like mine. The reason I am questioning it is he said it was too slow at only 92 beats per minute and now I am all worried. I guess I didn't think with the baby being only a 1/2 inch big you could hear the heart beat that early?? Is that possible??

My last question is.. The ultrasound guy pointed out a blood clot around the placenta. It was not very big and he said it was cloudy and that was a good thing. I didn't really know what that meant. Now, I am all concerned with there being a blood clot. Is this something that is common to see on early ultrasounds??

Thank you for your time! It is greatly appreciated!!!


First question: Anytime an ultrasound or the medical community dates a pregnancy, it always counts from the first day of your last period. You never have to add or subtract 2 weeks. If they told you, you were 5 weeks, that would mean 5 weeks from the first day of your last period.

If you wanted to know conception, you would count back to day 14 of your cycle.

As far as the sound of the doppler is concerned, as an RN you are probably used to the hand held doppler. I would not worry about that sound. It is somewhat concerning that the heart rate is under 100bpm. This is a reason for a close watch on the pregnancy, and a follow up ultrasound in a short interval to make sure the baby is growing properly.

Lastly, the clot is common in early pregnancy and is called a subchorionic bleed. This is where a small amount of blood gets in between the layers of the gestational sac. This also is a reason to do a short interval follow up. Most of the time these small bleeds resolve themselves into the second trimester.

Hope that covers all your questions.

With regards,
-- Jane, RDMS