Table 3 Sonographic criteria for interstitial pregnancy

Interstitial Pregnancy Ultrasound Criteria:

1. An empty uterine cavity [20].

2. A chorionic sac identified separately from the lateral edge of the uterine cavity by at least 1 cm [20].

3. A thin, 5 mm myometrial layer surrounding the chorionic sac [20].

4. Presence of an “interstitial line sign” or extension of endometrium to the gestational sac edge [21].