Double decidual sac sign
→ It consists of two concentric rings surrounding an anechoic gestational sac.
- The growing embryo pushes the central cavity complex and the decidua capsularis and parietalis are formed as 2 rings.
- The double decidual sac sign (DDSS) is a useful feature on early pregnancy ultrasound to confirm an early intrauterine pregnancy when the yolk sac or embryo is still not visualized.
- Where the two adhere is the decidua basalis, and is the site of future placental formation.
- If a double decidual sac sign is present (~53% of IUPs) , then it is highly suggestive that the intrauterine fluid collection is an intrauterine pregnancy .
- It is absent in many IUPs, however, and its absence does not define a Pseudo gestational sac
