A normal 20-week scan of a euploid fetus with a history of first-trimester increased nuchal translucency: caution or reassurance?

Clinical Course and Outcome of Non-Immune Fetal Hydrops in Singleton Pregnancies

Nonimmune fetal hydrops is a condition defined by abnormal fluid accumulation in two or more body compartments. The aim is to evaluate factors associated with adverse outcome in diagnosed fetal hydrops and to investigate the aspects for the decision making in the case of termination of pregnancy. Therefore, a retrospective data analysis of pregnancies complicated by non-immune hydrops fetalis between 2004 and 2018 was performed in a single tertiary referral center. Of 361 pregnancies with diagnosed fetal hydrops, in 183 cases (50.7%), the parents decided to terminate the pregnancy. A strong relationship between etiology and termination of pregnancy was demonstrated, whereas the highest rates of termination of pregnancy were found if a chromosomal aberration was diagnosed. Of the remaining 178 cases, 51 cases (28.7%) had a miscarriage, 33 cases (18.5%) had an intrauterine fetal death, and 94 cases (52.8%) were live born, whereas 26 (27.7%) of these offspring died within the first week of life. The risk of an adverse outcome increased with lower gestational age at diagnosis (p < 0.001). A nuchal translucency thickness greater than 2.5 mm was associated with an adverse outcome (p < 0.01). Furthermore, pregnancies with adverse outcome had significantly more affected compartments (median: 3; IQR 2), compared with live born cases (median: 2; IQR 1; p < 0.01). In conclusion, adverse outcome in pregnancies with fetal hydrops was associated with a lower gestational age at diagnosis, nuchal translucency greater than 2.5 mm and a higher count of affected compartments. These results confirm that a precise clinical workup to identify the underlying etiology of non-immune fetal hydrops is essential for a better prognostic assessment and accurate counselling of parents.

The associations of nuchal translucency and fetal abnormalities; significance and implications

This review of literature describes the first-trimester nuchal translucency (NT) which forms the basis of new form of screening which can lead to a significant improvement in detection of congenital anomalies as compared to second trimester screening programs, the so called genetic-sonogram. A growing body of evidence-based studies has demonstrated that fetal NT can be a powerful prenatal screening tool and combined with first trimester serum markers, it can be incredibly promising in near future. It should be expressed as Multiple of median (MoM) and maintained and monitored like any laboratory analyte. The aim of this review was to investigate the different hypotheses on the aetiology of increased NT. Using a computerized database (PubMed), articles on the aetiology of first-trimester NT were retrieved. Furthermore, the cited references of the retrieved articles were used to find additional articles. Based on ultrasonography, the associations of increased NT fetuses are described in relation with Down syndrome, Cardiac anomalies, and a diverse range of other anomalies. The review concludes that first trimester NT ultrasound has the potential to be used as an important tool for the detection of various congenital abnormalities and an early management can be implemented to reduce the mental trauma of expecting mothers by proper counseling and early diagnosis. For the precise measurements, it should be implemented in a meticulous and coherent manner.

First-trimester detection of structural abnormalities and the role of aneuploidy markers

OBJECTIVES

To determine the sensitivity of first-trimester ultrasound for diagnosing different structural anomalies in chromosomally normal pregnancies, and to establish the role of aneuploidy markers in the detection of abnormalities.

METHODS

This was a retrospective study of chromosomally normal singleton pregnancies with an 11-14-week scan performed in our center during 2002-2009. The ultrasound examination included an early fetal anatomy survey and assessment of nuchal translucency, ductus venosus blood flow and nasal bone.

RESULTS

Among 13 723 scanned first-trimester pregnancies with no genetic anomalies and complete follow-up, 439 fetuses (3.2%) were found to present with structural anomalies (194 with major anomalies and 245 with only minor anomalies). Forty-nine per cent of major structural anomalies were detected during the first-trimester scan, the highest rates corresponding to acrania (17/17), holoprosencephaly (three of three), hypoplastic left heart syndrome (10/10), omphalocele (six of six), megacystis (seven of eight) and hydrops (eight of nine). Higher than expected detection rates were obtained for skeletal (69%) and cardiac (57%) defects, coincidentally showing the highest presence of an increased nuchal translucency or abnormal ductus venosus blood flow (38% and 52%, respectively). The finding of an absent nasal bone did not appear to be associated with structural defects.

CONCLUSION

About half of major structural abnormalities can be diagnosed in the first trimester. Increased nuchal translucency or abnormal ductus venosus blood flow appear to be associated with cardiac and skeletal defects and may facilitate early detection.

Increased nuchal translucency in euploid fetuses--what should we be telling the parents?

Nuchal translucency (NT) measurement between 11 and 14 weeks' gestation is an undisputed marker for aneuploidies. When conventional karyotyping is normal, enlarged NT is a strong marker for adverse pregnancy outcome, associated with miscarriage, intrauterine death, congenital heart defects, and numerous other structural defects and genetic syndromes. The risk of adverse outcome is proportional to the degree of NT enlargement. Although the majority of structural anomalies are amenable to ultrasound detection, unspecified genetic syndromes involving developmental delay may only emerge after birth. Concern over these prenatally undetectable conditions is a heavy burden for parents. However, following detection of enlarged NT the majority of babies with normal detailed ultrasound examination and echocardiography will have an uneventful outcome with no increased risk for developmental delay when compared to the general population. Counseling should emphasize this to help parents restore hope in normal pregnancy outcome and infant development.