Which of the following evaluation methods is most sensitive in diagnosing pregnancy early?: (A) Serum pregnancy test, (B) Detection of fetal heart tones by Doppler equipment, (C) Abdominal ultrasound, (D) Bimanual exam to assess uterine size
Answer is A. A Doppler instrument will detect fetal cardiac action usually no sooner than 10 weeks.
A sensitive serum pregnancy test can detect placental HCG levels by 8 to 9 days post-ovulation, and it is therefore the most sensitive modality for detecting and diagnosing pregnancy.