Outcome of pregnancy in chromosomally normal fetuses with increased nuchaltranslucency in the first trimester

Objectives To study the outcome of chromosomally normal pregnancies with in creased nucbal translucency at the 10-14-week scary. Design Retrospective stud), of 1320 chromosomally normal singleton pregnanc ies with nuchal translucency of greater than or equal to3.5 mm. In addition to fetal karyotyping these patients were managed with follow-up scans at 1 4-16 and 20-22 weeks, specialist fetal echocardiography and in selected cas es by infection. screening and further genetic testing. Results In the 1320 pregnancies there were 68 (5.15%) spontaneous abortions or intrauterine deaths, 18 (1.36%) neonatal and infant deaths and 154 (11. 67%) terminations of pregnancy. In the 1080 (81.82%) survivors, 60 (5.56%) had abnormalities requiring medical or surgical treatment or leading to men tal handicap. The chance of a livebirth with, no defects in the group with nuchal translucency of 3.5-4.4 mm was 86%, for those with translucency of 4 .5-5.4 mm it was 77%, for those with translucency of 5.5-6.4 mm it was 67%, and for those with translucency of greater than or equal to 6.5 mm it was 31 %. Conclusions Increased fetal nuchal translucency, is associated with chromos omal abnormalities, many, fetal defects and genetic syndromes. In the major ity of cases a series of antenatal investigations, including fetal karyotyp ing, detailed scans, fetal echocardiography, as well as genetic testing and infection screening, that cart be completed by 20 weeks of gestation would distinguish between the pregnancies destined to result in adverse outcome and those leading to the delivery of infants without major defects.