Meron naba dito naka rinig ng heart beat using doppler at 4 to 5 w? I just heard mine!

Been using this doppler since last yr, coz i was preggy din. Tpos ngyon, i didnt exepct na ma detect na kaagad heart beat ni baby. Fyi. Sa lmp ko, im 4 w/6days but sa ultrasound ko, im 5 weeks and 5 days.