10 mm gestational sac how many weeks?
With a transvaginal probe, a 2- to 3-mm gestational sac can usually be seen by 5 weeks from the last menstrual period (Fig 1A). A yolk sac is usually seen by 6 menstrual weeks, or by the time the mean diameter of the sac has reached 10 mm (Fig 1B and Fig 1C).