Increased fetal nuchal translucency at 11–14 weeks

Nuchal translucency (NT) is the sonographic appearance of a subcutaneous collection of fluid behind the fetal neck. The measurement of fetal NT thickness at the 11–14-week scan has been combined with maternal age to provide an effective method of screening for trisomy 21; for an invasive testing rate of 5%, about 75% of trisomic pregnancies can be identified. When maternal serum free-β human chorionic gonadotrophin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11–14 weeks are also taken into account, the detection rate of chromosomal defects is about 90%. Increased NT can also identify a high proportion of other chromosomal abnormalities and is associated with major defects of the heart and great arteries, and a wide range of skeletal dysplasias and genetic syndromes. In monochorionic twins, discordancy for increased NT is an early marker of twin-to-twin transfusion syndrome (TTTS). As with the introduction of any new technology into routine clinical practice, it is essential that those undertaking the 11–14-week scan are adequately trained and their results are subjected to rigorous audit. Copyright © 2002 John Wiley & Sons, Ltd.     

Ultrasound diagnosis of structural abnormalities in the first trimester

The advances in ultrasound technology have made it possible to identify fetal structural abnormalities and genetic syndromes in the first trimester. First trimester prenatal diagnosis of fetal central nervous system, renal, gastrointestinal, cardiac, and skeletal abnormalities is reviewed. Copyright © 2002 John Wiley & Sons, Ltd.     

Association between fetal nuchal translucency thickness in first trimester and subsequent gestational hypertension and preeclampsia

Increased fetal nuchal translucency (NT) in the first trimester is associated with adverse pregnancy outcomes. Whether the increased NT is also associated with an increased frequency of pregnancy-associated hypertension (PAH) is not known. Seven hundred and seventy-nine pregnant women who received NT-based Down syndrome screening and delivered their babies at our hospital by September 2000 were enrolled into this study. Among these women, there are 46 cases of preeclampsia, 68 cases of gestational hypertension (GH); 665 women without any adverse pregnancy outcomes served as controls. Correlation analysis demonstrated that NT MoM (multiples of median) level had a positive association with maternal diastolic blood pressure at the time of admission for delivery (r = 0.104; p < 0.01). The severity of PAH was concordant with the stepwise increase of mean NT MoM level, which was 0.88 in control, 1.07 in gestational hypertension, and 1.13 in preeclampsia (p < 0.001). Using the 95th (1.52 MoM) and 90th (1.31 MoM) percentiles of NT thickness as cut-offs, the sensitivities and odds ratios of the women at risk for developing GH after 20 weeks of gestation were 8.8%, 19.1% and 1.98, 2.15 respectively, while for preeclampsia were 10.9%, 28.3% and 2.49, 3.58 respectively. It is concluded that the pathological changes in the placenta responsible for the development of PAH may also influence the physiological decrease of NT thickness in late first trimester. However, the sensitivity of fetal NT measurement in first trimester is not sufficient as a single marker for predicting the pregnant women at risk for subsequent PAH. Copyright © 2002 John Wiley & Sons, Ltd.     

Minor sonographic signs of trisomy 21 at 15–20 weeks' gestation in fetuses born without malformations: a prospective study

A prospective study was performed on 2119 pregnancies that underwent genetic amniocentesis. Indications for amniocentesis were either maternal age (⩾35) or triple-test results (risk⩾1/380). The study covered a 36-month period and assessed the prevalence of minor ultrasound markers both in fetuses with Down syndrome and normal control fetuses at 15–19 week' gestation. Only fetuses with normal karyotype or trisomy 21 were considered. Six minor sonographic markers were considered: nuchal thickness, pyelectasia, femur observed/expected and humerus observed/expected ratios, bowel echogenicity, and choroid plexus cysts. One or more ultrasound soft markers were present in 23 out of 33 fetuses with Down syndrome (70%) and in 572 out of 2069 normal fetuses (28%). Copyright © 2001 John Wiley & Sons, Ltd.