Institute for Women's Health, University College Hospital, London, UK.
Ultrasound Obstet Gynecol. 2021 Jan;57(1):149-154. doi: 10.1002/uog.23533.
To assess the diagnostic value and impact on management of visualizing on ultrasound an amniotic sac without a live embryo (amniotic sac sign). We also examined the potential effect on the number of follow-up visits in early pregnancy units of incorporating this sign into current diagnostic algorithms.
This was a prospective cohort study of all pregnant women who attended a single specialist early pregnancy unit from July 2017 to November 2018 with symptoms of pain and/or bleeding, or with a history of ectopic pregnancy or miscarriage, at < 14 weeks' gestation. Detailed initial ultrasound findings were documented, including whether an amniotic sac was present in a normally sited intrauterine pregnancy with absence of a live embryo. Women were followed up until a conclusive diagnosis was made.
The study included 6012 women who attended our unit with early pregnancy complications during the study period. A conclusive diagnosis was reached on the initial scan in 4221 (70.2%), whilst 1135 (18.9%) women had a pregnancy of uncertain viability and 656 (10.9%) had a pregnancy of unknown location (PUL). All women with a pregnancy of uncertain viability required follow-up ultrasound scans to differentiate between a live pregnancy and early embryonic demise. An amniotic sac in the absence of a live embryo was found in 174/1135 (15.3%) women with a pregnancy of uncertain viability at the initial ultrasound scan. The diagnosis of early embryonic demise was confirmed in all 134 of these women who attended their follow-up scans. The presence of an amniotic sac without a live embryo at the initial visit had a specificity of 100% (95% CI, 98.53-100.00%) and positive predictive value of 100% (95% CI, 97.2-100.0%) for the diagnosis of early pregnancy failure. A total of 1403/6012 (23.3%) women were asked to attend for a follow-up ultrasound scan to resolve diagnostic uncertainties, including 268/656 (40.9%) women with a PUL. The majority of follow-up scans needed to reach a conclusive diagnosis were in women with a pregnancy of uncertain viability (1135/1403 (80.9%)). By using the presence of the amniotic sac sign to diagnose early pregnancy failure at the first visit, the number of follow-up scans for pregnancies of uncertain viability would be reduced by 14.4%, which accounted for 11% of all follow-up scans during the study period.
The finding on ultrasound of an amniotic sac without a live embryo (amniotic sac sign) is a reliable marker of early pregnancy failure and could reduce the number of follow-up scans by 11% in cases of diagnostic uncertainty. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.
评估在超声检查中发现无存活胚胎的羊膜囊（羊膜囊征）的诊断价值及其对管理的影响。我们还研究了将该征象纳入当前诊断算法对早孕单位随访次数的潜在影响。
这是一项前瞻性队列研究，纳入了 2017 年 7 月至 2018 年 11 月在 14 周妊娠前因疼痛和/或出血就诊、有异位妊娠或流产史的单一专科早孕单位的所有孕妇。详细记录了初始超声检查结果，包括在正常位置的子宫内妊娠中是否存在羊膜囊，而无存活胚胎。对所有女性进行随访，直至做出明确诊断。
研究期间，该研究纳入了 6012 例因早孕并发症就诊的女性。在初始扫描中，4221 例（70.2%）得出了明确诊断，而 1135 例（18.9%）妊娠有存活的可能性，656 例（10.9%）妊娠位置不明（PUL）。所有妊娠有存活的可能性的女性都需要进行超声随访扫描，以区分存活妊娠和早期胚胎死亡。在初始超声检查中，1135 例妊娠有存活的可能性的女性中有 174 例（15.3%）发现无存活胚胎的羊膜囊。所有在随访中接受检查的这 134 例女性均确诊为早期胚胎死亡。在初诊时发现无存活胚胎的羊膜囊具有 100%的特异性（95%CI，98.53-100.00%）和 100%的阳性预测值（95%CI，97.2-100.0%），可诊断早孕失败。共有 1403 例（6012 例的 23.3%）女性被要求进行超声随访以明确诊断，包括 656 例（40.9%）PUL 患者。需要进行随访以明确诊断的大多数是妊娠有存活的可能性的女性（1135 例/1403 例（80.9%））。如果在初诊时使用羊膜囊征来诊断早孕失败，那么妊娠有存活的可能性的女性中需要进行的随访检查数量将减少 14.4%，这占研究期间所有随访检查的 11%。
超声检查中发现无存活胚胎的羊膜囊（羊膜囊征）是早期妊娠失败的可靠标志物，可将诊断不确定时的随访检查数量减少 11%。
