El Kateb A, Nasr B, Nassar M, Bernard J P, Ville Y
Department of Obstetrics and Gynecology, Paris-Ouest medical school, UVSQ, CHI Poissy-Saint Germain en Laye, France.
Prenat Diagn. 2007 Oct;27(10):922-5. doi: 10.1002/pd.1802.
To refine the incidence of abnormal first-trimester ultrasound measurements and their correlation with the outcome of monochorionic diamniotic pregnancies.
First-trimester crown-rump length (CRL) and nuchal translucency thickness (NT) measurements were studied in three subgroups of a total of 200 monochorionic twin gestations referred to our center between June 2002 and February 2006. Intertwin CRL discordance was defined as > 10% and the 95th percentile of NT thickness for gestational age was used. The first group of 103 consecutive unselected monochorionic diamniotic twin pregnancies was prospectively followed up from 11-14 weeks onwards, throughout the pregnancy. The second group of 136 nonconsecutive monochorionic diamniotic twin pregnancies including 64 that developed TTTS was studied retrospectively. The third group of 100 consecutive cases of TTTS studied retrospectively for the correlation between first trimester measurements and staging and timing of occurrence of TTTS.
In group 1, the incidence of TTTS was 5 in 103 (5%, 95CI [0.7-9]). Large intertwin CRL discordance and increased NT were correlated with perinatal death. In group 2, no significant association was found between first-trimester parameters and the development of TTTS but discordance in early second trimester biometry and Doppler were. In group three, a positive correlation was found between the intertwin discordance in CRL and early occurrence of TTTS before 20 weeks of gestation (p = 0.02).
Monochorionic twin gestations who ultimately develop TTTS may exhibit intertwin difference in growth as early as 11-14 weeks of gestation. The earlier the discordance the earlier the development of the disease.
细化孕早期超声测量异常的发生率及其与单绒毛膜双羊膜囊妊娠结局的相关性。
对200例单绒毛膜双胎妊娠进行研究，分为三个亚组，这些妊娠于2002年6月至2006年2月转诊至本中心。双胎间头臀长（CRL）不一致定义为>10%，并采用胎龄对应的NT厚度第95百分位数。第一组为103例连续入选的单绒毛膜双羊膜囊双胎妊娠，从孕11 - 14周起进行前瞻性随访直至整个孕期。第二组为136例非连续的单绒毛膜双羊膜囊双胎妊娠，其中64例发生了双胎输血综合征（TTTS），进行回顾性研究。第三组为100例连续的TTTS病例，回顾性研究孕早期测量值与TTTS分期及发病时间的相关性。
在第一组中，103例中有5例发生TTTS（5%，95%可信区间[0.7 - 9]）。双胎间CRL差异大及NT增加与围产儿死亡相关。在第二组中，孕早期参数与TTTS的发生无显著相关性，但孕中期早期生物测量和多普勒检查不一致则有关。在第三组中，发现双胎间CRL不一致与妊娠20周前TTTS的早期发生呈正相关（p = 0.02）。
最终发生TTTS的单绒毛膜双胎妊娠可能早在孕11 - 14周时就表现出双胎间生长差异。差异出现越早，疾病发展越早。
