Gestational sac
The gestational sac is the first structure visible on an early pregnancy ultrasound, typically appearing from around 4 to 5 weeks after your last menstrual period. It looks like a small, dark, fluid-filled oval within the lining of the uterus. Seeing a gestational sac confirms the pregnancy is in the uterus, which rules out an ectopic pregnancy. However, a sac alone does not confirm that the embryo is developing normally. Doctors look for the sac to grow at an expected rate and, by 6 weeks, for a yolk sac or embryo to appear inside it before confirming a viable pregnancy.
What This Means for You
Understanding Gestational 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
In Singapore, early scans are often done transvaginally for better accuracy in the first trimester. If your sac is seen but no embryo is visible yet, your doctor will usually schedule a follow-up scan within one to two weeks before drawing any conclusions.
Source: https://www.pregnancybirthbaby.org.au/glossary-of-pregnancy-and-labour
Always consult your healthcare provider for personalised advice.
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