Does Heartrate Drop as the Baby Gets Older?

QUESTION

Dear Ms Ultrasound,
I had a scan at 8 weeks and they said the fetal heartrate was 180 bpm. I bought a doppler and at 10 weeks the heartrate was 165, at 11 weeks it was 158 and at 12 weeks it was 150. The heart rate seems to be dropping by about 8 bpm a week. Is this normal or is my baby in trouble?

Regards,
Susan

ANSWER

Hi Susan,
A variable heart rate is quite normal. The heartbeat is normal anywhere between 120-170 on the average. If you imagine a very tiny heart beating it will have to beat or almost flutter to push enough blood through the fetal pole. As the heart grows bigger it does not have to beat as fast to be efficient.

Please be careful not to cause yourself undue anxiety with the doppler, reading too much, etc. It is so easy in this day an age to get caught up with so much science, forgetting to just actually enjoy the connection with your unborn child. Mother to child.

I give you permission to relax. Your baby sounds fine.

-- Jane, RDMS

Jane Foley

Jane Foley has worked as a Sonographer (Ultrasound Technologist) since 1979. Jane has lived and worked in many parts of the world including Saudi Arabia. She is a Registered Diagnostic Medical Sonographer or RDMS. She pulls a wealth of information from her experience in the field of Radiology and her interactions with such a broad cross-section of cultures she has visited. She now makes her home on the island of Maui with her English husband, Michael.