Anteroposterior Pelvic Diameter Research Articles

Severity of isolated fetal pyelectasis and risk of aneuploidy

Background: The risk of Down syndrome in the presence of isolated fetal pyelectasis is cited to be 1 in 340 (Corteville et al.). To date, no report on association of severity of isolated pyelectasis and risk of aneuploidy is published.Objective: To determine whether the severity of isolated fetal pyelectasis is associated with increased risk of aneuploidy.Study design: A retrospective cohort of 2,800 patients who underwent fetal anatomy sonogram for a variety of indications was obtained from our database. A total of 140 patients (0.05%) were found to have fetal pyelectasis. Forty cases of pyelectasis were diagnosed based on criteria cited by Corteville et al. (ie, an anteroposterior renal pelvic diameter of 4 mm or greater before 33 weeks or 7 mm or greater after 33 weeks). An experienced sonographer with a perinatologist performed all the sonograms. Fetal karyotype was determined prenatally or after delivery.Results: A total of 100 patients (0.036%) were found to have isolated fetal pyelectasis. Mean maternal age was 26.3 years (range, 15–42). Seventy-seven cases were diagnosed at less than 33 weeks. The range of pyelectasis was 4–21 mm in this group (mean, 11 mm). Twenty-three cases were diagnosed after 33 weeks; the range of renal pelvis dilation in this group was 7–29 mm (mean, 14 mm). None of the infants with isolated pyelectasis, regardless of severity, had aneuploidy.Conclusions: Severity of isolated pyelectasis did not appear to increase the risk of aneuploidy. Larger studies are required to confirm our findings.

A study of mild fetal pyelectasia ? outcome and proposed strategy of management

Mild fetal pyelectasia, defined as a renal pelvic anteroposterior (AP) diameter of 4-10 mm, has become a frequent finding on fetal ultrasonography. The natural history of such dilatation is unclear, resulting in confusion as to appropriate postnatal investigation and management. The aim of this study was to examine the urinary tract outcome of a series of infants with mild fetal pyelectasia demonstrated on routine morphology ultrasonogram between 16 and 21 weeks' gestation. Of the 37 cases identified, 13 (35%) went on to require medical or surgical intervention for significant urinary tract anomalies. These anomalies included pelvi-ureteric junction obstruction, dysplastic kidney, vesicoureteric reflux and posterior urethral valves. On initial scan all cases had an AP diameter of 4-8 mm and did not predict those infants who would go on to require intervention. An AP diameter of greater than 7 mm on repeat scans performed after 27 weeks' gestation had a positive predictive value of 0.92 and a negative predictive value of 0.76 for significant urinary tract anomaly requiring intervention. The specificity was 0. 94 and sensitivity 0.70. A protocol of one repeat antenatal ultrasound at 28-34 weeks' gestation would be able to identify those infants who would require postnatal investigation, using a measurement of >/=7 mm. The fetus with a normal repeat ultrasound would not require postnatal follow-up.

A study of mild fetal pyelectasia — outcome and proposed strategy of management

Mild fetal pyelectasia, defined as a renal pelvic anteroposterior (AP) diameter of 4–10 mm, has become a frequent finding on fetal ultrasonography. The natural history of such dilatation is unclear, resulting in confusion as to appropriate postnatal investigation and management. The aim of this study was to examine the urinary tract outcome of a series of infants with mild fetal pyelectasia demonstrated on routine morphology ultrasonogram between 16 and 21 weeks' gestation. Of the 37 cases identified, 13 (35%) went on to require medical or surgical intervention for significant urinary tract anomalies. These anomalies included pelvi-ureteric junction obstruction, dysplastic kidney, vesicoureteric reflux and posterior urethral valves. On initial scan all cases had an AP diameter of 4–8 mm and did not predict those infants who would go on to require intervention. An AP diameter of greater than 7 mm on repeat scans performed after 27 weeks' gestation had a positive predictive value of 0.92 and a negative predictive value of 0.76 for significant urinary tract anomaly requiring intervention. The specificity was 0.94 and sensitivity 0.70. A protocol of one repeat antenatal ultrasound at 28–34 weeks' gestation would be able to identify those infants who would require postnatal investigation, using a measurement of ≥7 mm. The fetus with a normal repeat ultrasound would not require postnatal follow-up. Copyright © 2000 John Wiley & Sons, Ltd.

The role of the renal resistive index ratio in diagnosing obstruction and in the follow-up of children with unilateral hydronephrosis.

To assess the role of the renal resistive index ratio (RIR) in discriminating equivocal upper urinary tract dilatation in children, and thus in establishing the need for surgery, in comparison with traditional diagnostic tools. The study comprised 40 children with unilateral hydronephrosis unrelated to vesico-ureteric reflux, posterior urethral valves, megaureter or a duplex system. In all patients one or more of the following 'indices of obstruction' were positive; an anteroposterior renal pelvic diameter of >20 mm, a half-time diuretic 'washout' (T/2) of > 20 min, a separate renal function of < 40%, and symptoms of obstruction (pain, sepsis). All these variables were measured on admission and after a mean (range) follow-up of 9 (2-24) months. After this period, all patients who were symptomatic or with two or more of the variables above the normal range were considered as obstructed and underwent a dismembered pyeloplasty. The variables were then re-assessed 6 months after surgery. The RIR was evaluated using duplex Doppler ultrasonography with a 3.5-5 MHz transducer, by the same operator. Differences between obstructive and unobstructive unilateral hydronephrosis were estimated from the mean values of the variables assessed and Student's t-test used to determine significant differences. The correlation between the T/2 and RIR before and after surgery was also evaluated. During follow-up the RIR was abnormal in 27 of 30 patients with hydronephrosis who were considered to be 'obstructed'. Twenty-three of these patients, selected for surgery, had a positive diuretic renogram; 11 had loss of differential renal function and 16 had recurrent clinical symptoms. There were significant differences in the mean RIR and T/2 between obstructed and unobstructed patients. Six months after dismembered pyeloplasty, the RIR returned to normal in all patients except three in whom it was previously > 1.1. The diuretic renogram, if initially showing pathology, always became normal. The RIR did not change in patients with an unchanged and severe loss of differential renal function before and after surgery. In this study the RIR was a good index of obstruction in children with unilateral hydronephrosis and it correlated well with the results of diuretic renography. The specificity of the RIR was reduced whenever there was severe renal damage.

Antenatal minimal hydronephrosis: is its follow-up an unnecessary cause of concern?

The aim of this study was to determine if follow-up of antenatally diagnosed minimal hydronephrosis (anteroposterior renal pelvis diameter <10 mm) is justified or if it is an unnecessary cause of concern for the parents involved. A case-control study, with subjects and controls selected from the Wessex Antenatally Detected Anomalies Register was performed. Information regarding antenatal and postnatal follow-up, renal tract morbidity and degree of concern was obtained from a parental questionnaire. 70 of the 115 subjects contacted (60.9 per cent) and 52 of the 81 controls (64.2 per cent) returned the questionnaire. 65 of the 70 subjects (92.9 per cent) were rescanned postnatally when 28 cases (43.1 per cent) had resolved. Coexisting ureteric and/or calyceal dilatation was evident postnatally in 12 cases and this group was significantly more likely to have underlying pathology than the group with isolated renal pelvis dilatation. Subjects were significantly more likely than controls to have a UTI. The degree of concern was significantly greater in the subject group and subject parents thought about the result significantly more often than controls. From our results we concluded that the follow-up of minimal hydronephrosis can be modified. There is no need for repeated antenatal scanning, a change that could reduce the level of parental anxiety. Postnatal follow-up is required in all patients to exclude an underlying uropathy but again this can be modified, with the majority of patients requiring only an ultrasound scan. This reduced intensity of investigation accompanied with careful explanation to the parents should help to minimize their concerns.

Isolated Mild Fetal Pyelectasis Detected by Transvaginal Sonography in Advanced Maternal Age

In Brief Objective To evaluate the importance and evolution of isolated, mild fetal pyelectasis, detected in early pregnancy by high-resolution transvaginal sonography, and to determine its association with abnormal fetal karyotypes. Methods Transvaginal scan at 11–16 weeks' gestation and transabdominal ultrasound examinations at the time of amniocentesis (16–18 weeks) were performed in 1093 pregnant women undergoing genetic amniocentesis because of advanced maternal age. In 795 cases, transabdominal scans were repeated at 22–24 weeks. Women were excluded if they had a spontaneous abortion, chose to terminate their pregnancy, or declined amniocentesis. Each patient was screened for fetal pyelectasis, defined as an increase in anteroposterior renal pelvic diameter, using cutoff values related to various stages of pregnancy. Results Isolated fetal pyelectasis was detected at the first ultrasound examination in 56 women (5.1%) in early pregnancy, in 32 (2.9%) at the time of amniocentesis, and in 23 (2.9%) at 22–24 weeks' gestation. Two fetuses with diagnoses of mild pyelectasis at the first transvaginal ultrasound demonstrated abnormal karyotypes at amniocentesis. In one case, the pyelectasis disappeared at 22–24 weeks' gestation. Conclusion This retrospective study shows that pyelectasis is more frequently detectable by high-resolution transvaginal sonography in the first half of pregnancy than in the second half. When detected in early pregnancy, the finding is frequently transient and not associated with an increased risk of abnormal fetal karyotypes. Mild fetal pyelectasis detected in early pregnancy by transvaginal sonography can be transient and does not indicate abnormal fetal karyotype.

Isolated mild fetal pyelectasis detected by transvaginal sonography in advanced maternal age

Objective: To evaluate the importance and evolution of isolated, mild fetal pyelectasis, detected in early pregnancy by high-resolution transvaginal sonography, and to determine its association with abnormal fetal karyotypes. Methods: Transvaginal scan at 11–16 weeks’ gestation and transabdominal ultrasound examinations at the time of amniocentesis (16–18 weeks) were performed in 1093 pregnant women undergoing genetic amniocentesis because of advanced maternal age. In 795 cases, transabdominal scans were repeated at 22–24 weeks. Women were excluded if they had a spontaneous abortion, chose to terminate their pregnancy, or declined amniocentesis. Each patient was screened for fetal pyelectasis, defined as an increase in anteroposterior renal pelvic diameter, using cutoff values related to various stages of pregnancy. Results: Isolated fetal pyelectasis was detected at the first ultrasound examination in 56 women (5.1%) in early pregnancy, in 32 (2.9%) at the time of amniocentesis, and in 23 (2.9%) at 22–24 weeks’ gestation. Two fetuses with diagnoses of mild pyelectasis at the first transvaginal ultrasound demonstrated abnormal karyotypes at amniocentesis. In one case, the pyelectasis disappeared at 22–24 weeks’ gestation. Conclusion: This retrospective study shows that pyelectasis is more frequently detectable by high-resolution transvaginal sonography in the first half of pregnancy than in the second half. When detected in early pregnancy, the finding is frequently transient and not associated with an increased risk of abnormal fetal karyotypes.

Detection and assessment of pyelectasis in the fetus: relationship to postnatal renal function

Objective: To assess the relationship between fetal pyelectasis determined by ultrasonography and postnatal renal function. Methods: We first established normal values for anteroposterior, transverse, and longitudinal diameters of the renal pelvis sonographically in 68 normal fetuses at 30–40 weeks’ gestation. We also evaluated prospectively the relationship between the severity of pyelectasis (diameter at least two standard deviations above the normal mean) in 36 fetuses at 30–40 weeks’ gestation and postnatal renal function. Fetal renal function also was evaluated through measurement of the hourly urine production rate, whereas postnatal renal function was assessed by technetium 99m–diethylenetriamine penta-acetic acid renography and excretory urography. Results: Fetal pyelectasis was diagnosed when renal pelvic diameters were at least 8 mm (anteroposterior), 11 mm (transverse), and 14 mm (longitudinal), all upper limits of normal diameters of 68 normal fetuses as determined in the first part of the study. Pyelectasis was associated with a normal urine production rate in all fetuses, but in six fetuses it was associated with a normal urine production rate in all fetuses, but in six fetuses it was associated with a progressive deterioration of renal function within the 1st month of life, requiring neonatal surgery. In the other 30 fetuses with pyelectasis, who did not require neonatal surgery, pyelectasis decreased gradually or totally disappeared within 2 years. Renal pelvic anteroposterior, transverse, and longitudinal pelvic diameters were at least 20, 25, and 26 mm, respectively, during late fetal life in those neonates at the time of corrective surgery. The mean anteroposterior diameter in those fetuses who did not require surgery at infancy (11 ± 6 mm) was significantly less than in those requiring surgery (33 ± 14 mm, P < .01). Likewise, the transverse diameters were 17 ± 10 mm and 38 ± 16 mm ( P < .01) and the longitudinal diameters were 20 ± 10 mm and 48 ± 22 mm ( P < .01). Conclusion: Neonatal surgery is recommended when the anteroposterior, transverse, and longitudinal renal pelvic diameters during the prenatal period are at least 20, 25, and 26 mm, respectively. Surgery is not necessary when the diameters are less than 20 mm.

Effect of Maternal Hydration on Fetal Renal Pyelectasis

Objective To assess the effect of maternal hydration on fetal pyelectasis. Methods Thirteen pregnant women with fetal pyelectasis and 13 controls matched for gestational age were recruited during the same period. Ultrasound and Doppler studies and maternal urine specific gravity measurements were carried out before and after maternal oral hydration. The data were analyzed by either a two- or three-factor analysis of variance. Results Renal artery Doppler pulsatility index was significantly greater in the study group than in the controls (2.37 versus 1.83; P = .009) and this finding was unaffected by maternal hydration status. After hydration, the maternal urinary specific gravity decreased significantly (1.018 versus 1.009; P < .001), the amniotic fluid index (AFI) increased significantly (14.27 versus 18.24 cm; P < .001), and the fetal renal pelvis diameter increased significantly (0.29 versus 0.46 cm; P = .002) in both the study and control groups. Renal pelvis anteroposterior diameter after hydration did not differ significantly whether the fetal bladder was full or empty (0.7 versus 0.6 cm; P = .1). In this study, each subject served as her own control (ie, from before to after hydration). Three of 13 controls met the diagnostic criteria for pyelectasis after maternal hydration. Conclusion The AFI increases after maternal hydration in both normal fetuses and those with pyelectasis. The fetal renal pelvis anteroposterior diameter increases with maternal hydration in both normal fetuses and those with pyelectasis and is independent of the state of the fetal bladder. The renal artery Doppler pulsatility index is significantly greater in fetuses with pyelectasis than in controls.

Effect of Maternal Hydration on Fetal Renal Pyelectasis

Objective: To assess the effect of maternal hydration on fetal pyelectasis. Methods: Thirteen pregnant women with fetal pyelectasis and 13 controls matched for gestational age were recruited during the same period. Ultrasound and Doppler studies and maternal urine specific gravity measurements were carried out before and after maternal oral hydration. The data were analyzed by either a two- or three-factor analysis of variance. Results: Renal artery Doppler pulsatility index was significantly greater in the study group than in the controls (2.37 versus 1.83; P = .009) and this finding was unaffected by maternal hydration status. After hydration, the maternal urinary specific gravity decreased significantly (1.018 versus 1.009; P < .001), the amniotic fluid index (AFI) increased significantly (14.27 versus 18.24 cm; P < .001), and the fetal renal pelvis diameter increased significantly (0.29 versus 0.46 cm; P = .002) in both the study and control groups. Renal pelvis anteroposterior diameter after hydration did not differ significantly whether the fetal bladder was full or empty (0.7 versus 0.6 cm; P = .1). In this study, each subject served as her own control (ie, from before to after hydration). Three of 13 controls met the diagnostic criteria for pyelectasis after maternal hydration. Conclusion: The AFI increases after maternal hydration in both normal fetuses and those with pyelectasis. The fetal renal pelvis anteroposterior diameter increases with maternal hydration in both normal fetuses and those with pyelectasis and is independent of the state of the fetal bladder. The renal artery Doppler pulsatility index is significantly greater in fetuses with pyelectasis than in controls.

Screening for Obstructive Uropathy in Rural Egyptian Children 1784

Aim: The purpose of this study was to determine the prevalence and etiologies of obstructive uropathy in rural Egyptian children.Methods: Children residing in four villages representing four different geographical areas in the Sohag governorate were examined with portable sonographic equipment, using 3.5 and 5 MHz transducers, and also received complete physical examinations. Those diagnosed with obstructive uropathy were referred to Sohag University Hospital for further investigation.Results: 4,137 children (2,281 male and 1,856 female) aged 0-18 years were examined. Obstructive uropathy was detected in 69 children (1.7%). Twenty-nine children had mild pyelocaliectasis (anteroposterior renal pelvic diameter 10-15 mm). Twenty-one of these 29 children were infants less than 1 year of age, 28/29 had unilateral pyelocaliectasis, and 29/29 had no obstruction identified by intravenous pyelography and in addition had normal voiding cystourethrograms. Urinary tract stones were found in 14 children (11 unilateral). Other diagnoses included ureteral stricture (n = 5, 2 congenital, 3 with bilharziasis), ureteropelvic junction obstruction (4), meatal stenosis(4), urethral stricture (4), posterior urethral valves (3), neurogenic bladder(2), phimosis (2), ureterocele (1) and localized hydrocalicosis (1).Conclusions: Significant, treatable causes of obstructive uropathy were found in 0.9% (40/4,137) of rural Egyptian children. The high frequency of urinary tract stones is most likely attibutable to the hot, dry weather of upper Egypt, where Sohag is located. We believe that this prevalence of obstructive uropathy is sufficient to justify screening renal ultrasound in Egyptian children.

Uropathies malformatives de diagnostic anténatal: prise en charge néonatale et devenir de 100 enfants nés entre 1988 et 1990 au CHU d'Angers

Malformative uropathies diagnosed in utero are increasing in number. This work describes the decision strategy adopted in Angers concerning the neonatal handling of those abnormalities. Patients and methods. — One hundred children born between 1988 and 1990, with prenatally suspected fetal uropathy, were included in the study and followed for a period of 3 years. In every case, an ultrasound scan was performed at birth. In cases with persistent abnormality, a voiding cystourethrography was done in the first week of life. An intravenous urograph and/or a nuclear renography were performed during the second month of life. Results. — Twenty-nine children were normal. Seventy-one were affected by 126 isolated or related uropathies; the most frequent ones were the ureteropelvic junction obstruction syndrome (48), ureterovesical junction obstruction (18) and muticystic kidneys (13). A vesicoureteral reflux was associated in 22% of cases. The diagnosis was perfectly correlated with the prenatal diagnosis in 50% of cases. Fourteen of the normal children had a later ultrasound scan control, between 2 and 9 months; later on, three of them showed a moderate ureteropelvic junction obstruction syndrome. Amongst the 48 ureteropelvic junction obstruction syndromes, 22% have been operated on. The others obstructive uropathies remained stable or spontaneously improved. Discussion. — These results require us to discuss as matter of priority the large number of spontaneously regressive prenatal hydronephrosis and the necessity to establish a consensus for the pre and postnatal pathological thresholds of the anteroposterior pelvic diameter, the interest in carrying out a voiding cystography after the birth when dilatation is confirmed, the interest of nuclear renography for the diagnosis and follow-up of obstructive uropathies and the absence of urgency for surgery. Conclusion. — We propose a decision tree specifying the action to take when facing the diagnosis of a prenatal hydronephrosis. It could be a part of the reflection for the medical teams handling these uropathies in the aim of a consensual attitude which is now essential.

A prospective study of the association between isolated fetal pyelectasis and chromosomal abnormality

To determine the incidence of chromosomal abnormalities among fetuses with isolated pyelectasis. Between March 1991 and March 1994, 121 cases of isolated fetal pyelectasis were identified at our institution. Pyelectasis was defined as a renal pelvis anteroposterior diameter of at least 4 mm before 33 weeks' gestation, and at least 7 mm at 33 weeks or thereafter. Once identified, women were offered antenatal genetic testing; if they declined, consent was sought for umbilical cord blood studies at delivery. Chromosomal evaluation was available in 99 women. Two chromosomal abnormalities were identified: one trisomy 21 and one mosaic 46, XY/47, XYY. The ages of the women were 32 and 28 years, respectively. Calculation of adjusted risks for Down syndrome and all chromosomal abnormalities indicated a 3.9-fold increase in Down syndrome risk and a 3.3-fold increase in risk for all chromosomal abnormalities in the presence of isolated fetal pyelectasis. Isolated fetal pyelectasis is associated with increased risk, over that related to age, for both Down syndrome and all chromosomal abnormalities. These factors may be valuable in counseling individual patients regarding the appropriateness of amniocentesis.

Sonographic Renal Parenchymal and Pelvicaliceal Areas

We determined better quantitative parameters for renal sonography and applied these parameters to the evaluation and followup of prenatal hydronephrosis. We retrospectively reviewed normal renal ultrasound studies of 120 children and serial ultrasound studies of 40 with prenatal hydronephrosis. Renal length, bipolar parenchymal thickness and anteroposterior pelvic diameter were measured from serial sonograms of patients with hydronephrosis. Renal longitudinal parenchymal area and renal longitudinal pelvicaliceal area were determined from the sonograms of normal children and from serial studies of patients with hydronephrosis using computer planimetry. Data from normal children were plotted to construct a renal parenchymal area growth chart. Length and area measurements were compared using regression analysis. The ability of these parameters to predict patients who would require pyeloplasty was examined. Normal parenchymal area correlated well with normal renal length (r2 = 0.92). Differential parenchymal area correlated with differential function (r2 = 0.75), while differential length and bipolar thickness correlated poorly with function (r2 = 0.01 and 0.42, respectively). The ratio of parenchymal-to-pelvicaliceal area differentiated patients with unilateral hydronephrosis requiring pyeloplasty from those treated conservatively. The ratio was less than 1.6 in all patients requiring pyeloplasty and greater than 1.6 in those followed conservatively. Renal parenchymal area provides a more accurate estimate of renal size and function in the hydronephrotic kidney than traditional 1-dimensional measurements. In our limited series the ratio of renal parenchymal-to-pelvicaliceal area allowed the prediction of patients who required pyeloplasty.

Sonographic Renal Parenchymal and Pelvicaliceal Areas: New Quantitative Parameters for Renal Sonographic Followup

Purpose We determined better quantitative parameters for renal sonography and applied these parameters to the evaluation and followup of prenatal hydronephrosis. Materials and Methods We retrospectively reviewed normal renal ultrasound studies of 120 children and serial ultrasound studies of 40 with prenatal hydronephrosis. Renal length, bipolar parenchymal thickness and anteroposterior pelvic diameter were measured from serial sonograms of patients with hydronephrosis. Renal longitudinal parenchymal area and renal longitudinal pelvicaliceal area were determined from the sonograms of normal children and from serial studies of patients with hydronephrosis using computer planimetry. Data from normal children were plotted to construct a renal parenchymal area growth chart. Length and area measurements were compared using regression analysis. The ability of these parameters to predict patients who would require pyeloplasty was examined. Results Normal parenchymal area correlated well with normal renal length (r 2 = 0.92). Differential parenchymal area correlated with differential function (r 2 = 0.75), while differential length and bipolar thickness correlated poorly with function (f 2 = 0.01 and 0.42, respectively). The ratio of parenchymal-to-pelvicaliceal area differentiated patients with unilateral hydronephrosis requiring pyeloplasty from those treated conservatively. The ratio was less than 1.6 in all patients requiring pyeloplasty and greater than 1.6 in those followed conservatively. Conclusions Renal parenchymal area provides a more accurate estimate of renal size and function in the hydronephrotic kidney than traditional 1-dimensional measurements. In our limited series the ratio of renal parenchymal-to-pelvicaliceal area allowed the prediction of patients who required pyeloplasty.

Correlation of Prenatal Renal Pelvic Anteroposterior Diameter with Outcome in Infancy

Purpose We attempted to correlate prenatal renal pelvic anteroposterior diameter with outcome in infancy. Materials and Methods Between May 1992 and March 1994 we identified 27 cases of fetal hydronephrosis in which renal pelvic anteroposterior diameter was 4 mm. or greater before 33 weeks of gestation and 7 mm. or greater at or after 33 weeks of gestation. Results Hydronephrosis was bilateral in 18 fetuses and unilateral in 9. Shortly after birth radiological assessment revealed vesicoureteral reflux in 6 neonates, ureteropelvic junction obstruction in 6, extrarenal pelves in 3 and persistent nonobstructive hydronephrosis in 4. Radiological evaluation was normal in 8 newborns. Conclusions When these screening criteria for hydronephrosis are met prenatally a complete radiological assessment should be done following birth.

Correlation of Prenatal Renal Pelvic Anteroposterior Diameter with Outcome in Infancy

Correlation of Prenatal Renal Pelvic Anteroposterior Diameter with Outcome in Infancy

Evaluation of prenatally diagnosed hydronephrosis by morphometric measurements of the kidney.

A large number of hydronephrotic kidneys (108) were diagnosed prenatally in 69 infants between 1987 and 1991 and subsequently confirmed postnatally. Prenatal morphometric measurements were done in order to find reliable parameters for the detection of a group at risk for surgical treatment. A second aim of the study was to describe the natural history and management of hydronephrosis detected prenatally. We devised a classification of postnatal obstructive uropathy using ultrasonography and the renal scan. Accordingly, we classified the patients as having mild, moderate or severe hydronephrosis. A renal pelvic antero-posterior diameter (APD) of 9 mm or more, and a pelvic-to-renal APD ratio of 0.45 before 32 weeks of gestation and 0.52 thereafter, were found to be useful for the detection of severe outcome. Our new parameter, a pelvic-to-renal volume ratio of greater than 0.08, can also be used for this purpose.

The accuracy of antenatal ultrasonography in identifying renal abnormalities.

To determine the accuracy of measuring antenatal renal pelvic diameter for prediction of renal abnormalities. Prospective evaluation of all pregnant women undergoing ultrasonography. A teaching hospital providing primary and referral maternity care. Fifty-six pregnant women with suspected fetal hydronephrosis or cystic lesions identified from 7500 ultrasonograms over 3 years. Antenatal renal pelvic diameter was measured in the anteroposterior dimension. Neonates underwent postnatal ultrasonography after day 3 of life; if the results were abnormal, a cystogram and renal diuretic scan were obtained. None of 50 kidneys 15 mm or smaller in anteroposterior pelvic diameter had obstruction; 11 (79%) of 14 kidneys larger than 15 mm were obstructed or demonstrated vesicoureteral reflux. Of 12 kidneys believed to be multicystic before birth, five (42%) proved to have hydronephrosis. Since the majority of fetuses with suspected hydronephrosis proved to be normal, parents should not be unduly alarmed by the physician. Renal pelvic diameter of more than 15 mm is strongly predictive of hydronephrosis. Since severe hydronephrosis is treatable and can be mistaken for a multicystic kidney antenatally, full radiologic evaluation is needed soon after birth.

Congenital hydronephrosis: Correlation of fetal ultrasonographic findings with infant outcome

Although congenital hydronephrosis is a common fetal disorder, ultrasonographic criteria for prenatal diagnosis remain poorly defined. In this study prenatal ultrasonographic findings were correlated with postnatal outcome in 63 fetuses with suspected hydronephrosis. Prenatal ultrasonographic measurements included length, anteroposterior diameter, and transverse diameter of the kidney and renal pelvis, as well as dorsal renal parenchymal thickness. In 45 of the 63 fetuses, hydronephrosis was confirmed postnatally. These infants were divided into two groups on the basis of renal status: (1) abnormal renal function and/or surgery required (n = 31) and (2) normal renal function with no surgery required (n = 14). The anteroposterior diameter of the renal pelvis was the simplest and most sensitive technique for prenatal diagnosis of congenital hydronephrosis, allowing identification of 100% of cases. Postnatal follow-up studies are warranted if an anteroposterior pelvic diameter is greater than or equal to 4 mm before 33 weeks or greater than or equal to 7 mm after 33 weeks.