The Value of Increased Nuchal Translucency(NT) for the Prediction of Abnormal Pregnancy Outcome

Kim, Eun Sung; Han, Ho Won; Ryu, Hyun Mee; Yang, Jae Hyuk; Kim, Mun Young; Yoo, Shi Jun; Lee, Young Ho; Han, Jung Ryol; Lee, Kyung Sang

Abstract

PURPOSE: To evaluate the NT in the first trimester associated with fetal chromosomal abnormality, fetal structural abnormality and adverse pregnancy outcome.
METHODS
From Mar. 1993 to Dec. 1997, 133 cases of increased NT were reviewed retrospectively. All these fetues were taken a karyotyping and/or a high resolution ultrasonography for associated anomaly. The NT was measured by transvaginal ultrasonography(TVS) and transabdominal ultrasonography(TAS) if difficulty was encountered with TVS in the period of the 10th-14th week of gestation. The increased NT is approved when it is over 3mm.
RESULTS
Of these 133 cases, 102 cases(76.7%) revealed normal outcomes and 31 cases(23.3%) revealed abnormal outcomes such as chromosomal abnormality, structural abnormality and adverse pregnancy outcome, The mean value of NT was 3.44+/-0.68mm in the normal group and 4.93+/-2.70mm in the abnormal group, respectively. The chromosomal abnormalities were found in 16 of the 31 cases: nine Down SD, two Patau syndrome, one Tuner synrome, one triploidy, one 46, XX,i(18q), one 47,iso(Xp)/46,XX one confined placental mosaicism. In 12 cases of the 31 cases, the structural anomalies were detected. Of these 12 cases, 3 cases were eventually developed to cytsic hygroma, 3 cases were cardiac anomaly, 3 cases were renal anomaly, 1 case was congenital diaphragmatic hernia, 1 case was skeletal dysplasia and 1 case was suspected syndrome. The adverse pregnancy outcome such as intrauterine growth restriction, intrauterine fetal death and preterm labor was revealed in 3 cases. In the cases of NT over 7mm, the result was 100% abnormal outcome.
CONCLUSION
Increased NT in the first trimester could be a highly efficient the predictor for detection of chromosomal abnormality, structural anomaly and adverse pregnancy outcome.