Week 6 - Gestational Age (Fetal age 4 weeks)
5 ½ to 6 ½ weeks is usually a very good time to detect either a
fetal pole or even a
fetal heart beat by vaginal ultrasound. The
fetal pole is the first visible sign of a developing embryo. This pole structure actually has some curve to it with the embryo’s head at one end and what looks like a tail at the other end. The fetal pole now allows for crown to rump measurements (CRL) to be taken, so that pregnancy dating can be a bit more accurate.