This Fetal Doppler is all about hearing, and connecting to your baby. with that said...

This product is not intended to diagnose any medical condition and it should not be used to come to a conclusion based on its findings. In any way is a replacement for a medical doctor. Please consult your medical practitioner on the use.

Furthermore...

Please note that if you are trying to get the reading of the fetal heart rate in the early stages of the pregnancy, the heartbeat may not be strong enough to hear or the baby could be in a position that doesn’t allow the Fetal Doppler scanner to obtain a clear reading of the heart rate. In this case, it might be wise to try again in a few minutes or the following day. Most of the good readings are between the week 9th to 14th.

Sometimes the sound waves will echo causing it to sound like there are two babies in the womb, but each baby will have different heart rates, so don't panic, unless of course, you are expecting twins.