kindly ask your OB on what to follow.
my OB advised that we follow my 1st TVS dahil maaaring magbago ang EDD ng 2nd or 3rd trimester dahil depende sa size ni baby.
if normal ang cycle, you can follow based from LMP.
also, maaaring hindi rin yan masusunod. ang EDD ay 40weeks. pero maaari kang manganak atleast 37 weeks as the safest.