At what menstrual age is the yolk sac generally visible?

The yolk sac is typically visible on ultrasound around the 5-week menstrual age mark. This structure plays an important role in early embryonic development, providing nutrients to the developing embryo before the placenta is fully formed.

During this time, the yolk sac appears as a small, round structure within the gestational sac. Its identification is crucial for confirming an intrauterine pregnancy and assessing early developmental health. Before 5 weeks, the structures may not be well-defined or visible, which is why it is important for clinicians to recognize the timeline for its visual appearance.

In summary, understanding the visibility of the yolk sac at 5 weeks helps in evaluating early pregnancy viability and assessing normal physiological development.