Yolk sac
The yolk sac is a small, round structure visible on ultrasound from about 5 to 6 weeks of pregnancy. Before the placenta is fully formed, it supplies nutrients and oxygen to the developing embryo and plays a key role in early blood cell production. A visible yolk sac on a transvaginal scan is a reassuring sign that the pregnancy is progressing inside the uterus, not in the fallopian tube. Its size and shape give sonographers useful clues about how the embryo is developing. An unusually large, small, or irregular yolk sac may prompt closer monitoring in the weeks that follow.
What This Means for You
Understanding Yolk sac is an important part of your first trimester journey. During pregnancy, your care team will use this term regularly. Being familiar with it means you can ask better questions and feel more confident at your antenatal appointments.
Explore our Pregnancy hubGood to Know
At KKH and NUH, yolk sac findings are always interpreted alongside gestational age and hCG levels, so a single scan result rarely tells the full story. If your doctor recommends a repeat scan in one to two weeks, this is standard practice and not necessarily a cause for alarm.
Related Terms
Source: https://my.clevelandclinic.org/health/articles/7247-fetal-development-stages-of-growth
Always consult your healthcare provider for personalised advice.
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