At what gestational age can a fetus typically be detected by pelvic ultrasound?

A fetus can typically be detected by pelvic ultrasound around 5 to 6 weeks of gestation. At this stage, a transvaginal ultrasound can identify the gestational sac, which is the earliest sign of pregnancy. By 5 to 6 weeks, it is often possible to see the yolk sac and even the fetal pole, marking the initial development of the embryo.

Detection earlier than this, around 3 to 4 weeks, is not generally possible due to the early stage of gestation when the embryo is still very small and may not yet be visibly discernible. By 7 to 8 weeks, although the fetal structures can be detected, the clearer visualization of the embryonic features and heart motion becomes more typical, making the 5 to 6 weeks a more accurate timeframe for initial detection. By 10 to 12 weeks, the fetus is much more developed and distinct, but this falls outside the question's focus on the earliest detection.