Best confirmation for pregnancy at six weeks:
In pregnant woman undergoing TVS Gestational sac :4 and half weeks yolk sac :5 weeks fetal node :5 and half weeks fetal hea :6weeks TEXTBOOK OF OBSTETRICS,SHEILA BALAKRISHNAN,Pg no:475,2nd edition
USG for cardiac activity
Doppler
estimation of serum beta-hCG
Bimanual palpation
Diagnosis in obstetrics