Fetal pyelectasis in consecutive pregnancies: a possible genetic predisposition

The recurrence of sonographic 'soft markers': ominous sign or 'just' genetics?

OBJECTIVES

'Soft markers' (SMs) are nonspecific findings that might convey a higher risk for Down syndrome. We sought to determine the recurrence rate of the most common SM in subsequent pregnancies.

METHODS

This is a retrospective study of all women who underwent early or late fetal sonographic anatomical screening in our ultrasound unit. The examined SMs were pyelectasis, thickened nuchal fold (TNF) and echogenic intracardiac foci (EIF). Data on recurrence and pregnancy outcome were retrieved retrospectively.

RESULTS

The database included 20 672 singleton pregnancies; SMs were detected in 2347 (11.1%) of the fetuses and were isolated in 1739 (74%). Rates of solitary findings in the pregnancies were 6.5% (1360/20 672) EIF, 3% (624/18 850) TNF and 1.7% (363/20 672) pyelectasis. The recurrence rate of EIF, TNF and pyelectasis in subsequent consecutive pregnancies was 21%, 27% and 16%, respectively. Overall, 62 cases of Down syndrome were diagnosed in (1 : 333 pregnancies). No cases were diagnosed in patients with recurrent SMs.

CONCLUSION

The high recurrence rate of solitary SM implies for genetic predisposition. These results might improve our counseling for pregnant women affected by the reappearance of solitary SM. Further studies are needed to assess the likelihood ratio for SM if recurrence occurs. © 2017 John Wiley & Sons, Ltd.

Fetal genitourinary anomalies--a pictorial review with postnatal correlation

An accurate diagnosis of fetal genitourinary abnormality is essential because some genitourinary abnormalities are associated with pulmonary hypoplasia, which ultimately affects the neonatal outcome. Adrenal masses are rare; however, presence of any lesion located at the superior pole of the kidney should raise the possibility of an adrenal mass. Fetal genital anomalies are rare as well and some of the most difficult to diagnose. A combination and pattern of findings allows for specific diagnosis of renal tract abnormalities. This article reviews the imaging appearance of fetal genitourinary abnormalities with perinatal imaging correlation where available.

Mild pyelectasis diagnosed by prenatal ultrasound is not a predictor of urinary tract morbidity in childhood

OBJECTIVES

To determine whether children with prenatally diagnosed mild pyelectasis have more urinary tract morbidity during childhood than children without this finding.

METHODS

Case-control study in children with pyelectasis (anteroposterior diameter of the fetal renal pelvis of 5-10 mm). A validated questionnaire was sent to the parents of 208 cases and 416 matched controls.

RESULTS

The questionnaire was returned by 146 cases and 250 controls. There was a male predominance in the case group (p = < 0.0001). There was no difference in voiding habits or in prevalence of urinary tract infections (UTI). The prevalence of UTI was high: 11.6% in cases and 10.0% in controls. The only difference was a higher prevalence of constipation in the case group (p = 0.003). Postnatally, 41 children had an ultrasound examination and 16 were referred to a paediatrician or urologist: 3 had persisting pyelectasis, 3 had a recurrent UTI and 1 required surgery (a pyeloplasty). Four of the controls were referred to a paediatrician or urologist: 3 had recurrent UTI and 1 had urinary incontinence.

CONCLUSION

Children with a mild fetal pyelectasis do not have more urinary tract morbidity during childhood than children without this finding. Therefore, there seems to be no need for additional investigation after birth.

Isolated fetal pyelectasis and chromosomal abnormalities

OBJECTIVE

The primary objective of this study was to determine if isolated pyelectasis is a risk factor for trisomy 21.

STUDY DESIGN

Twelve thousand, six hundred and seventy-two unselected singleton fetuses were examined by prenatal ultrasound during the second trimester at a single institution. The sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio of pyelectasis (either isolated or in association with other soft markers/structural anomalies) to detect trisomy 21 were calculated.

RESULTS

Pyelectasis (anteroposterior pelvic diameter >/=4 mm) was detected in 2.9% (366/12,672) of the fetuses. Among these, 83.3% (305/366) were isolated, and 16.7% (61/366) were associated with other markers/structural anomalies. The prevalence of trisomy 21 was 0.087% (11/12,672) and, among these fetuses, 2 (18.1%) had pyelectasis, 1 isolated, and 1 associated with other markers/structural anomalies. The presence of isolated pyelectasis had 9.09% sensitivity, 97.6% specificity, 0.33% positive predictive value, and 99.9% negative predictive value to detect fetuses with trisomy 21. The likelihood ratio of trisomy 21 in this group of fetuses was 3.79 (95% CI 0.582-24.616). Among fetuses with pyelectasis and other associated markers/structural anomalies, the sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio for trisomy 21 were 9.09%, 99.5%, 1.64%, 99.9%, and 19.2 (95% CI 2.91-126.44).

CONCLUSION

In the absence of other findings, isolated pyelectasis is not a justification for the performance of an amniocentesis.

Nuchal translucency measurements in consecutive normal pregnancies. Is there a predisposition to increased levels?

OBJECTIVE

The current study aims to assess the relative risk of isolated increased nuchal translucency (NT) in consecutive normal pregnancies.

METHODS

A retrospective search of the fetal medicine unit database in which NT assessment was conducted. Only singleton fetuses with an unremarkable pregnancy outcome were included in this study. The repeated NT either at a threshold of >2.5 mm or > or =95th centile of the normal range for various CRLs (2 mm at a CRL < or =44 mm to 2.85 mm at CRLs 83-84 mm) was assessed. Pearson's correlation was applied to investigate any correlation between a log(10) NT obtained in two consecutive pregnancies. The chance of an increased NT in the first pregnancy followed by similar results in the subsequent one was assessed using Fisher's exact test.

RESULTS

Ninety-two pregnant women with two consecutive normal pregnancies were identified. There was a highly significant correlation between the log(10) NT values measured in the consecutive pregnancies (r = 0.38; p < 0.001). The relative risk of an isolated NT > or =2.5 mm in the first pregnancy to be followed by a similar finding in the subsequent one was 18.21 (95% confidence interval [CI]: 3.62-91.55). The relative risk of an isolated NT > or =95th centile in the first pregnancy to be followed by a similar result in the subsequent one was 21 (95% CI: 4.53-97.44).

CONCLUSION

The current results indicate a significant correlation of NT values in consecutive unaffected pregnancies. There also was a predisposition for a repeated isolated increased NT in subsequent pregnancies. Additional series and more information are needed before firm conclusions can be made.

Mild dilatation of renal pelvis in term neonates with urinary tract infection

The purpose of this study was to assess the incidence and evolution of mild dilatation confined to the renal pelvis in term neonates with urinary tract infection developing within 2 weeks from birth. Twenty-two neonates with mild dilatation of the renal pelvis out of 180 neonates with urinary tract infection were identified giving an incidence of 12.2% for this finding. Male to female ratio was 6.3:1. The left kidney was twice as frequently involved (68 vs. 32%). At follow-up, the dilatation had disappeared in 20 neonates (90.9%) by a mean age of 2.7 years with only one neonate developing two further episodes of urinary tract infection in the infantile period. No other morbidity was noted.

Ultrasound screening for fetal chromosome anomalies

Ultrasound evidence for aneuploidy may be found in almost every organ of the fetus and can be used to modify the risk of aneuploidy. The diagnosis of these minor anomalies on second-trimester ultrasonography will increase the risk of an abnormal karyotype whereas the absence of these findings may reduce this danger. The most specific and most ominous isolated markers for fetal aneuploidy are nuchal findings (edema or cysts), indicating the need to obtain a fetal karyotype in all cases irrespective of maternal age or results of biochemical serum screening. Hyperechoic fetal bowel is apparently also a strong indicator of fetal aneuploidy. Other isolated sonographic markers may increase the risk of an abnormal karyotype three- to ninefold. Most sonographic markers for aneuploidy specify an increased risk for Down syndrome, but choroid plexus cysts are apparently more specific for trisomy 18. Along with other screening methods, ultrasound screening for fetal aneuploidy should be used routinely to identify additional pregnancies at need for evaluation of fetal karyotype.

Borderline genitourinary tract abnormalities

The ability to detect major malformations of the fetal urinary tract using diagnostic antenatal ultrasound is well-known. Serious obstructive or dysgenetic abnormalities are often clearly seen and their implications well-known. Less clear is the meaning of mild or minimal pyelectasis, unilateral renal agenesis, nonvisualization of the fetal bladder, and pelvic kidneys. Fetal pyelectasis rarely, if ever, is associated with a need for neonatal intervention if the diameter of the pelvis is less than 10 mm. Although mild pyelectasis occurs in up to 25% of Down syndrome fetuses, the risk of Down syndrome in the case of isolated pyelectasis in a low-risk population is less than 1 in 340. Mild pyelectasis by itself does not seem to justify invasive testing for fetal karyotype. Nonvisualization of the fetal bladder carries a high risk of renal agenesis or dysplasia, whereas unilateral renal agenesis and a fetal pelvic kidney seem to carry limited, if any, negative implications.