Most impoant investigation for ectopic pregnancy:: (A) Serial f3-hCG levels, (B) Transvaginal USG, (C) Progesterone measurement, (D) Culdocentesis
Answer is B. If TVS reveals an intrauterine gestational sac,the diagnosis of ectopic can usually be ruled out .sometimes a psuedosac may be seen in an ectopic due to bleeding produced by separation of a decidual cast.(refer pgno:159 sheila 2 nd edition)