2) Does it come with the gel?
No, you can easily buy it on pharmacy or use other lubricant.
Yes, this is just a hearing device, it doesn't transmit or emit radiation.
4) At what week can I start using this?
The recommended is starting on the 12th week and onwards.
The Fetal Doppler is all about hearing, and connecting to your baby. That being 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. It is not a replacement for a medical doctor and recommended ultrasound check by your obstetrician. Please consult your medical practitioner on the use.
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 may be in a position that doesn’t allow the fetal doppler 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.