Figure 1: Transvaginal ultrasound shows a mean sac diameter of 30 mm (about 8 weeks gestational age). S = gestational sac.
Figure 2: Further scan demonstrates a fetal pole (arrow) without a yolk sac. There is minimal decidual reaction.
- Most common cause = chromosomal abnormality leading to arrested development
- Diagnosis is made by:
- CRL > 5 mm but no cardiac activity
- MSD >/= 8 mm but no yolk sac
- MSD >/= 16 mm but no embryo
- Embryo seen but no yolk sac
- No cardiac activity in embryo seen by transabdominal ultrasound (need to confirm with transvaginal ultrasound if early IUP)