Background: Giving birth to a new life is something that every couple looks forward to. Pregnancy brings huge physical and psychological challenges to women. If you want to give birth to a healthy baby, timely prenatal check-up and intervention are necessary. As a painless and non-invasive diagnostic tool, B-ultrasound plays a very important role in pregnancy examination. So, how long after pregnancy can you see the gestational sac through B-ultrasound examination? When the gestational sac forms The gestational sac is a structure that develops in the early embryo before the placenta begins to form. Generally speaking, the fertilized egg undergoes cell division and movement in the fallopian tube, and finally