Increased first trimester nuchal translucency: pregnancy and infant outcomes after routine screening for Down's syndrome in an unselected antenatal population.

Abstract

Although increased nuchal translucency (NT) has been linked to a wide range of fetal chromosomal abnormalities and genetic syndromes, very few studies have looked at the outcomes of chromosomally normal pregnancies in unselected obstetric populations. This study aims to evaluate the outcomes of pregnancies with nuchal translucency measurements greater than or equal to 4 mm in a low risk obstetric population attending for routine first trimester screening. Women attending for booking scans were routinely offered nuchal translucency measurement as a screening test for Down's syndrome between 10 and 14 weeks gestation. The prevalence of increased nuchal translucency was 0.8% (n = 53). There were 15 (28.3%) chromosomal abnormalities, the commonest of which was Down's syndrome. Of the 38 chromosomally normal pregnancies, seven resulted in intrauterine death, early neonatal death or termination of pregnancy. The remaining 31 cases resulted in livebirths, of which two infants now exhibit developmental delay of unknown aetiology and one has been diagnosed as having Noonan's syndrome. 10 (19%) pregnancies were diagnosed as having major anatomical malformations resulting in fetal or neonatal demise or requiring postnatal surgery. In a routine obstetric population, the finding of an NT measurement greater than or equal to 4 mm is associated with a poor pregnancy outcome in the majority of cases, mainly owing to chromosomal abnormality. This study establishes the need for focused fetal assessment in cases with such first trimester findings.

Translucência nucal aumentada e cariótipo normal: evolução pré e pós-natal

“…However, this corroborates the findings of studies that assessed increased NT in fetuses with normal kar yotype and found variability in the association with structural malformations, chiefly hear t defects, ranging from 4.8 to 32.1%. 8,10,11,18,19, In the present study, the chances of major structural malformation, detected in the prenatal period, also grew as NT increased, and therefore propor tions were close to the ones described by other authors.1,6,7 Nonetheless, as we observed, most malformations (78.6%) were detected in the first or second trimester. Malformations that were not diagnosed in the prenatal evaluation (unilateral, bilateral clubfoot and microtia) were isolated cases and were not associated with delayed brain development.…”

“…However, few studies have focused on the follow-up of liveborn infants with history of increased fetal NT, normal karyotypes and normal ultrasound scans. 7 Bekker 3 assessed nine studies [6][7][8][9][10][11][12][13][14] with postnatal follow-up (0-84 months) of euploid fetuses with increased NT and without fetal malformation, and noticed that the level of compromised brain development during childhood ranged from 0 to 8.7%. Nevertheless, only two of these studies used a control group.…”

Noonan Syndrome: Clinical Aspects and Molecular Pathogenesis

“…Among fetuses with normal chromosomes, the diagnosis of NS will be made in approximately 1-3% of cases with nuchal edema in the first trimester [Reynders et al, 1997;Adekunle et al, 1999;Nisbet et al, 1999;Hiippala et al, 2001]. Since height and weight are usually normal in newborns with NS, parameters of fetal growth are not helpful in making the diagnosis.…”

Use of the combined first‐trimester screen result and low PAPP‐A to predict risk of adverse fetal outcomes

“…Most literature has focused on the individual components of the screen; increased fetal NT (Adekunle et al, 1999;Souka et al, 2001;Cheng et al, 2004;Dugoff et al, 2004;Kabili et al, 2004;Krantz et al, 2004), low maternal PAPP-A (Ong et al, 2000;Ochshorn et al, 2001;Yaron et al, 2002a;Kwik and Morris, 2003;Dugoff et al, 2004;Kabili et al, 2004;Krantz et al, 2004) and abnormal free *Correspondence to: Sandie L. Barrett, Western Diagnostic Pathology, Symbion Health, Western Australia, Australia. E-mail: sandieb@aapt.net.au β-hCG levels (Ong et al, 2000;Yaron et al, 2002b;Dugoff et al, 2004;Kabili et al, 2004;Krantz et al, 2004) and their associations with adverse pregnancy outcomes.…”