Why does heartbeat does not show in ultrasound?

Answer 1

* A visit to your obstetrician would be prudent. You could discuss this with him or her instead of worrying -- hopefully, very unnecessarily.

However, difficulty could arise if the fetus is still too small. In addition, the position of the fetus (the baby's back), and the placenta's position might obscure the ultrasound.

A contributor who is a doctor adds the following:

* An ultrasound is not 100%. It uses high-frequency sound waves created by a piezoelectric "chip" that converts electricity into sound and vice-versa. There could be a few reasons why the machine can't detect the heartbeat of your fetus:

First, there may be an amount of bone between your baby's heart and the transceiver of the probe. Bone is a very dense material and ultrasound waves won't be transmitted through this material in much the same way that you can't see through rock; an ultrasound can't "see" through bone. The fetus could be in a position that its spine or pelvis is in the way of the waves.

Second, the ultrasound technician "might" not be very good. I'd ask for a radiologist (a licensed medical doctor) to do the scan rather than a radiographic technologist. Radiologists are very much more skilled and experienced in reading ultrasounds and also in positioning the probe in such a fashion as to provide the best chance of picking up the baby's heartbeat.

Third, the machine being used might not be capable of picking up the heartbeat except in the most optimal of circumstances. Older machines can have resolution problems.

As long as the baby's heartbeat can be picked up via auscultation techniques, i.e., with a stethoscope, I'd not worry about it. But, I say that the reason is probably either due to bone in the way, or else the tech is not very good.