Department of Medical Imaging, University of Toronto, Toronto, ON.
Department of Radiology, McMaster University, St. Joseph's Healthcare Hamilton, Hamilton, ON.
J Obstet Gynaecol Can. 2021 Sep;43(9):1055-1061. doi: 10.1016/j.jogc.2020.11.020. Epub 2021 Jan 29.
To evaluate the current ultrasound diagnostic criteria for non-viable pregnancy in the first trimester.
We conducted a retrospective chart review involving 3 tertiary care institutions. Consecutive first-trimester ultrasound reports between January 2013 and June 2016 were reviewed. All first-trimester ultrasound examinations performed to assess pregnancy viability with adequate imaging or clinical follow-up were included. Inclusion criteria based on follow-up were adequate imaging to document ongoing intrauterine pregnancy or clinical follow-up demonstrating viability or non-viability. Data on mean sac diameter (MSD), yolk sac presence/diameter, embryo presence/length, presence of a heartbeat, and heart rate were collected. This was followed by a retrospective validation review of another consecutive cohort.
Two hundred and forty-five examinations with a viable-pregnancy outcome and 301 examinations with a non-viable pregnancy outcome were reviewed. The main predictor of non-viable pregnancy was an MSD of ≥20 mm in the absence of a yolk sac (positive predictive value [PPV] 100%; 95% CI 93%-100%), embryo (PPV 100%; 95% CI 90%-100%), or heartbeat (PPV 100%; 95% CI 96%-100%]). Other predictors of non-viability were a measurable embryo without a yolk sac (PPV 100%; 95% CI 91%-100%), yolk sac diameter ≥8 mm (PPV 100%; 95% CI 91%-100%), and absence of heartbeat with an embryo ≥3 mm (PPV 100%; 95% CI 97%-100%). These findings were confirmed in a validation cohort of 45 viable and 53 non-viable pregnancies, with the exception of 1 case of viable pregnancy with no heartbeat and an embryo length 3.3 mm. Based on the median daily growth of 1.2 mm in the viable cohort, 21% of follow-up ultrasound examinations were performed too early for an MSD threshold of 20 mm and 55%, for an MSD threshold of 25 mm.
In our cohort, MSD ≥20 mm in the absence of yolk sac or an embryo with heartbeat always predicted a non-viable pregnancy.
评估早孕期无活力妊娠的当前超声诊断标准。
我们进行了一项回顾性图表审查，涉及 3 家三级保健机构。回顾了 2013 年 1 月至 2016 年 6 月期间连续进行的首次孕期超声报告。所有进行首次孕期超声检查以评估妊娠活力的检查均包括适当的影像学检查或临床随访。基于随访的纳入标准是有足够的影像学证据证明宫内妊娠持续存在或临床随访证明有活力或无活力。收集了平均孕囊直径（MSD）、卵黄囊存在/直径、胚胎存在/长度、胎心存在和心率的数据。随后对另一组连续队列进行了回顾性验证审查。
对 245 次有活力妊娠结局的检查和 301 次无活力妊娠结局的检查进行了回顾。无活力妊娠的主要预测因素是在没有卵黄囊的情况下 MSD 大于 20mm（阳性预测值[PPV]100%；95%置信区间 93%-100%）、胚胎（PPV 100%；95%置信区间 90%-100%）或胎心（PPV 100%；95%置信区间 96%-100%）。无活力的其他预测因素是无卵黄囊的可测量胚胎（PPV 100%；95%置信区间 91%-100%）、卵黄囊直径大于 8mm（PPV 100%；95%置信区间 91%-100%）和胚胎大于 3mm 时无心音（PPV 100%；95%置信区间 97%-100%）。在 45 例有活力和 53 例无活力妊娠的验证队列中证实了这些发现，但有 1 例有活力妊娠无心音且胚胎长度为 3.3mm。根据有活力组中平均每日增长 1.2mm，对于 MSD 阈值为 20mm，21%的随访超声检查进行得太早，对于 MSD 阈值为 25mm，55%的随访超声检查进行得太早。
在我们的队列中，在没有卵黄囊或有胎心的胚胎的情况下，MSD 大于 20mm 总是预测无活力妊娠。
