Presentation
Pregnant. Dates unkown.
Patient Data
There is rounded, anechoic structure located eccentric to the endometrial cavity (intradecidual sign) - in keeping with an intrauterine gestational sac. The clip images (second stack) show more clearly the presence of a double decidual sign. Appearance is therefore compatible with an intrauterine gestational sac with a high level of certainty, even though no yolk sac or embryo are visible at this stage.
Note the incidental presence of bilateral corpora lutea.
Case Discussion
An intrauterine gestational sac without a visible embryo with a heartbeat constitutes a pregnancy of uncertain viability. A repeat ultrasound should be performed, in a timeframe whereby the diagnosis of either a viable pregnancy or a miscarriage can be made definitively, as ongoing uncertainty and numerous scans could exacerbate the patient's anxiety.
Based on the landmark paper by Preisler et al 1, re-scan is recommended as follows:
MSD <12 mm with no embryo - rescan in 14 days
- if MSD has not doubled and there is still no embryo - diagnosis of failed pregnancy can be made
MSD 12-25 mm with no embryo - rescan in 7 days
- if no embryo with cardiac activity present - diagnosis of failed pregnancy can be made.
Please refer to the relevant article on pregnancy of uncertain viability (PUV) for further diagnosis and follow-up guidelines.
Note that quantitative bHCG has no role in the diagnosis of pregnancy failure - criteria are based on ultrasound only. Therefore, the radiology report does need to recommend serial bHCG in the follow-up of PUV.