Is It Normal To See A Yolk Sac But No Embryonic Pole At 5 Weeks 4 Days Gestation?

Uterus is gravid with a single we dem gestational sac, the MSD of which measures 13 mm corresponding to 5 weeks 4 days. A yolk sac is seen but no identifiable embryonic nodule noted at this time. No subchorionic bleed is seen. Adnexae, cervix and cul de sac are unremarkable. Is this normal?