Carver Alissa, Haeri Sina, Moldenhauer Julie, Wolfe Honor M, Goodnight William
Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
J Ultrasound Med. 2011 Mar;30(3):297-301. doi: 10.7863/jum.2011.30.3.297.
Twin-twin transfusion syndrome complicates up to 15% of monochorionic diamniotic gestations. Current recommendations for sonographic surveillance in monochorionic diamniotic pregnancies for detection of twin-twin transfusion syndrome vary. Our objective was to determine an appropriate frequency of sonographic surveillance to optimize detection of twin-twin transfusion syndrome in monochorionic diamniotic gestations.
A retrospective cohort analysis of all nonanomalous monochorionic diamniotic twins delivered at the University of North Carolina over a 9-year period was performed. The rate and gestational age of twin-twin transfusion syndrome onset were calculated. The time to the diagnosis of twin-twin transfusion syndrome was evaluated by a Kaplan-Meier survival curve; clinical factors at initial sonography were examined for their use in prediction of twin-twin transfusion syndrome.
Of the 577 twin deliveries, 145 (25%) were monochorionic diamniotic and included for analysis. The rate of twin-twin transfusion syndrome was 17.93% (n = 26). The mean frequency of surveillance ± SD before diagnosis of twin-twin transfusion syndrome was 3.1 ± 2.1 weeks. The mean gestational age at diagnosis of twin-twin transfusion syndrome was 21.3 ± 3.4 weeks (range, 15-29 weeks). Both a discordant maximum vertical amniotic fluid pocket (>65% difference) and a discordant estimated fetal weight (>25% difference) at initial sonography showed a significantly shorter time to diagnosis of twin-twin transfusion syndrome (P < .0001).
Evaluation for twin-twin transfusion syndrome should begin in the second trimester. Weekly surveillance for those pregnancies with estimated fetal weight or maximum vertical pocket discordance is recommended. For those with a concordant estimated fetal weight and maximum vertical pocket, sonographic evaluation every 2 weeks is warranted to 28 to 30 weeks. After that, development of twin-twin transfusion syndrome is less likely, and a different paradigm of antenatal testing may be reasonable.
双胎输血综合征在单绒毛膜双羊膜囊妊娠中发生率高达15%。目前关于单绒毛膜双羊膜囊妊娠超声监测以检测双胎输血综合征的建议各不相同。我们的目的是确定合适的超声监测频率，以优化单绒毛膜双羊膜囊妊娠中双胎输血综合征的检测。
对北卡罗来纳大学9年间分娩的所有非畸形单绒毛膜双羊膜囊双胎进行回顾性队列分析。计算双胎输血综合征的发生率和发病孕周。采用Kaplan-Meier生存曲线评估双胎输血综合征的诊断时间；检查初次超声检查时的临床因素在预测双胎输血综合征中的应用。
在577例双胎分娩中，145例（25%）为单绒毛膜双羊膜囊，纳入分析。双胎输血综合征的发生率为17.93%（ n = 26）。诊断双胎输血综合征前监测的平均频率±标准差为3.1±2.1周。双胎输血综合征诊断时的平均孕周为21.3±3.4周（范围15 - 29周）。初次超声检查时最大羊水深度不一致（差异>65%）和估计胎儿体重不一致（差异>25%）均显示双胎输血综合征的诊断时间显著缩短（P <.0001）。
双胎输血综合征的评估应在孕中期开始。对于估计胎儿体重或最大羊水深度不一致的妊娠，建议每周监测。对于估计胎儿体重和最大羊水深度一致的妊娠，每2周进行一次超声评估直至孕28至30周是必要的。此后，发生双胎输血综合征的可能性较小，采用不同的产前检查模式可能是合理的。
