Scott R F, Featherstone T, Hussey J K
Clin Radiol. 1987 Mar;38(2):127-30. doi: 10.1016/s0009-9260(87)80007-7.
The major concern when an empty gestation sac is encountered during threatened abortion is whether or not the pregnancy is viable. Viable pregnancies are managed expectantly, whereas non-viable pregnancies are treated by evacuation of the uterus. Early evacuation of the non-viable pregnancy spares the patient considerable anxiety and discomfort. This study shows that a single ultrasound examination is useful in differentiating viable from non-viable empty gestation sacs. The size of the empty gestation sac was found to be the most useful criterion for determining non-viability. Empty gestation sacs with sizes greater than 26 mm were non-viable, a specificity of 100%, accounting for 43% (42 out of 102) of patients in our series. Other ultrasound criteria found to be useful were shape, position, wall and decidual reaction. The positive predictive value for a successful outcome to a pregnancy was low, being only 41% (9 out of 22).
在先兆流产时遇到空妊娠囊，主要关注点在于妊娠是否存活。存活的妊娠采用期待治疗，而非存活的妊娠则通过清宫治疗。早期清除非存活妊娠可使患者免受相当大的焦虑和不适。本研究表明，单次超声检查有助于区分存活与非存活的空妊娠囊。发现空妊娠囊大小是确定非存活状态最有用的标准。大小大于26 mm的空妊娠囊是非存活的，特异性为100%，在我们的系列研究中占43%（102例中的42例）患者。其他有用的超声标准包括形状、位置、囊壁和蜕膜反应。妊娠成功结局的阳性预测值较低，仅为41%（22例中的9例）。
