Pregnancy
The yolk sac appears within the gestational sac around five and a half weeks and is one of the first signs that a pregnancy is developing as expected. Its appearance is noted at the early viability scan after IVF.
Sources
- Royal Australian and New Zealand College of Obstetricians and Gynaecologists (ranzcog.edu.au)
- Healthdirect Australia (healthdirect.gov.au)
Last reviewed: 10 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.