Appendix 4 for the New Zealand Obstetric Ultrasound Guidelines.
Whatu Tāniko pattern
Pseudogestational sac
Occurs in 5 percent of ectopic pregnancies
Irregular fluid collection, centrally within endometrial cavity
Irregular shape
No double decidual reaction
No yolk sac
May be difficult to differentiate from early intrauterine pregnancy or decidual cyst
A decidual cyst and early gestational sac are usually eccentric
A pseudosac is central and often contains blood clot or mobile debris.
Free fluid or haemoperitoneum
Describe free fluid as simple or complex.
Quantify the amount, that is, small, moderate, large, deepest pocket, confined to pelvis, present in upper abdomen, etc. Document fluid at or above the uterine fundus.
If small amount of simple fluid, ectopic is likely not ruptured.
A small amount of complex fluid does not always indicate rupture. This can be due to leak from the end of the tube, but early rupture is not excluded.
A moderate to large amount of complex fluid / haemoperitoneum is suggestive of rupture.