Transfusion policy after severe postpartum haemorrhage: a randomised non-inferiority trial.

OBJECTIVE: To assess the effect of red blood cell (RBC) transfusion on quality of life in acutely anaemic women after postpartum haemorrhage. DESIGN: Randomised non-inferiority trial. SETTING: Thirty-seven Dutch university and general hospitals. POPULATION: Women with acute anaemia (haemoglobin 4.8-7.9 g/dl [3.0-4.9 mmol/l] 12-24 hours postpartum) without severe anaemic symptoms or severe comorbidities. METHODS: Women were allocated to RBC transfusion or non-intervention. MAIN OUTCOME MEASURES: Primary outcome was physical fatigue 3 days postpartum (Multidimensional Fatigue Inventory, scale 4-20; 20 represents maximal fatigue). Non-inferiority was demonstrated if the physical fatigue difference between study arms was maximal 1.3. Secondary outcomes were health-related quality of life and physical complications. Health-related quality of life questionnaires were completed at five time-points until 6 weeks postpartum. RESULTS: In all, 521 women were randomised to non-intervention (n = 262) or RBC transfusion (n = 259). Mean physical fatigue score at day 3 postpartum, adjusted for baseline and mode of delivery, was 0.8 lower in the RBC transfusion arm (95% confidence interval: 0.1-1.5, P = 0.02) and at 1 week postpartum was 1.06 lower (95% confidence interval: 0.3-1.8, P = 0.01). A median of two RBC units was transfused in the RBC transfusion arm. In the non-intervention arm, 33 women received RBC transfusion, mainly because of anaemic symptoms. Physical complications were comparable. CONCLUSIONS: Statistically, non-inferiority could not be demonstrated as the confidence interval crossed the non-inferiority boundary. Nevertheless, with only a small difference in physical fatigue and no differences in secondary outcomes, implementation of restrictive management seems clinically justified.

Age dependency of coagulation parameters during childhood and puberty.

BACKGROUND: Use of age-adjusted reference values is crucial for correct diagnosis and management of thrombotic and hemorrhagic disease in children. They vary with utilized reagents and analyzers. OBJECTIVES: We established reference values with the Sysmex CA-1500 System and in parallel with the Behring BCS System using reagents from Siemens Healthcare Diagnostics Products GmbH. METHODS: After informed consent, blood samples were obtained from 218 healthy children and 52 healthy adults, grouped as 1-6 months (n = 29), 7-12 months (n = 25), 1-5 years (n = 57), 6-10 years (n = 57), 11-18 years (n = 50) and > 19 years (n = 52). RESULTS: Most coagulation parameters demonstrate good comparability between analyzers with the exception of PT and APTT. Single coagulation factors fibrinogen, factor (F) II, FIX, FXI and XII were significantly decreased in the youngest children; the strongest age dependency was found for coagulation inhibitors Protein C and S, both significantly decreased in infancy and young childhood. We confirmed that high levels of von Willebrand factor are found in the youngest children without increased levels of FVIII followed by decreased von Willebrand levels in the subsequent age group. In children with blood group O a less distinct increase in time was found, compared with individuals with one of the other blood groups. CONCLUSIONS: The correlation between the CA-1500 and the BCS system was remarkable. Differences were most pronounced between children < 12 months and older children and adults, confirming the phenomenon of developmental hemostasis. The rationale for age-related changes in the hemostatic system remains unraveled. Our results underline the need for age-specific reference ranges.

Should cervical favourability play a role in the decision for labour induction in gestational hypertension or mild pre-eclampsia at term? An exploratory analysis of the HYPITAT trial.

OBJECTIVE: To examine whether cervical favourability (measured by cervical length and the Bishop score) should inform obstetricians' decision regarding labour induction for women with gestational hypertension or mild pre-eclampsia at term. DESIGN: A post hoc analysis of the Hypertension and Pre-eclampsia Intervention Trial At Term (HYPITAT). SETTING: Obstetric departments of six university and 32 teaching and district hospitals in the Netherlands. POPULATION: A total of 756 women diagnosed with gestational hypertension or pre-eclampsia between 36 + 0 and 41 + 0 weeks of gestation randomly allocated to induction of labour or expectant management. METHODS: Data were analysed using logistic regression modelling. MAIN OUTCOME MEASURES: The occurrence of a high-risk maternal situation defined as either maternal complications or progression to severe disease. Secondary outcomes were caesarean delivery and adverse neonatal outcomes. RESULTS: The superiority of labour induction in preventing high-risk situations in women with gestational hypertension or mild pre-eclampsia at term varied significantly according to cervical favourability. In women who were managed expectantly, the longer the cervix the higher the risk of developing maternal high-risk situations, whereas in women in whom labour was induced, cervical length was not associated with a higher probability of maternal high-risk situations (test of interaction P = 0.03). Similarly, the beneficial effect of labour induction on reducing the caesarean section rate was stronger in women with an unfavourable cervix. CONCLUSION: Against widely held opinion, our exploratory analysis showed that women with gestational hypertension or mild pre-eclampsia at term who have an unfavourable cervix benefited more from labour induction than other women. TRIAL REGISTRATION: The trial has been registered in the clinical trial register as ISRCTN08132825.

Size and volume charts of fetal kidney, renal pelvis and adrenal gland.

OBJECTIVE: To establish reference curves for size and volume of the fetal kidney, renal pelvis and adrenal gland, as measured using ultrasound from the 15(th) week of gestation. METHODS: This was a prospective, longitudinal study of 96 fetuses in low-risk singleton pregnancies, in which we performed serial ultrasound examinations at 4-week intervals. The length and anteroposterior and transverse diameters of both kidneys, the anteroposterior and transverse diameters of the renal pelvises and the length of the adrenal glands were measured three times at each examination, with the average being used for further analysis. Reference charts were constructed using multilevel statistical analysis and comparisons were made with previously published charts derived from cross-sectional data. RESULTS: We present nomograms for fetal kidney dimensions and volume, renal pelvis dimensions and adrenal gland length. The new charts show differences in shape and have narrower percentile bands in comparison to previously published reference ranges. CONCLUSIONS: These new charts of measurements of the fetal kidney, renal pelvis and adrenal gland, from a prospective, longitudinal study, may be useful in the diagnosis and assessment of pathology of the kidney and adrenal gland.

An economic analysis of induction of labour and expectant monitoring in women with gestational hypertension or pre-eclampsia at term (HYPITAT trial).

OBJECTIVE: To assess the economic consequences of labour induction compared with expectant monitoring in women with gestational hypertension or pre-eclampsia at term. DESIGN: An economic analysis alongside the Hypertension and Pre-eclampsia Intervention Trial At Term (HYPITAT). SETTING: Obstetric departments of six university and 32 teaching and district hospitals in the Netherlands. POPULATION: Women diagnosed with gestational hypertension or pre-eclampsia between 36(+0) and 41(+0) weeks of gestation, randomly allocated to either induction of labour or expectant monitoring. METHODS: A trial-based cost-effectiveness analysis was performed from a societal perspective during a 1-year time horizon. MAIN OUTCOME MEASURES: One-year costs were estimated and health outcomes were expressed as the prevalence of poor maternal outcome defined as either maternal complications or progression to severe disease. RESULTS: The average costs of induction of labour (n = 377) were €7077 versus €7908 for expectant monitoring (n = 379), with an average difference of -€831 (95% CI -€1561 to -€144). This 11% difference predominantly originated from the antepartum period: per woman costs were €1259 for induction versus €2700 for expectant monitoring. During delivery, more costs were generated following induction (€2190) compared with expectant monitoring (€1210). No substantial differences were found in the postpartum, follow-up and for non-medical costs. CONCLUSION: In women with gestational hypertension or mild pre-eclampsia at term, induction of labour is less costly than expectant monitoring because of differences in resource use in the antepartum period. As the trial already demonstrated that induction of labour results in less progression to severe disease without resulting in a higher caesarean section rate, both clinical and economic consequences are in favour of induction of labour in these women. TRIAL REGISTRATION: The trial has been registered in the clinical trial register as ISRCTN08132825.

Incidence of additional genetic changes in the TEL and AML1 genes in DCOG and COALL-treated t(12;21)-positive pediatric ALL, and their relation with drug sensitivity and clinical outcome.

Clinical heterogeneity within t(12;21) or TEL/AML1-positive ALL (25% of childhood common/preB ALL) indicates that additional genetic changes might contribute to outcome. We studied the relation between additional genetic changes in TEL(ETV6) and AML1(RUNX1) (FISH), drug sensitivity (MTT assay) and clinical outcome in 143 DCOG and COALL-treated t(12;21)-positive ALL patients. Additional genetic changes in TEL and AML1 were present in 83% of the patients, and consisted of (partial) deletion of the second TEL gene (70%), an extra AML1 gene (23%) or an extra der(21)t(12;21) (10%). More than one additional change was observed in 20%. Disease-free survival (pDFS) of DCOG patients without additional genetic changes (4 years pDFS +/- s.e. 53 +/- 17%) and of those with an extra der(21)t(12;21) (60 +/- 22%) is poorer than that of compared to patients with other additional genetic changes in TEL or AML1 (79 +/- 6%; P-trend = 0.02). This was mainly due to the occurrence of early relapses within 2.5 years after the first diagnosis. Similar observations were found in the COALL cohort, albeit not significant owing to limited follow-up. Multivariate analysis including age, WBC and genetic abnormalities in TEL and/or AML1 showed that especially, in vitro resistance to prednisolone (hazard ratio 5.78, 95% CI 1.45-23.0; P=0.01) is an independent prognostic factor in DCOG- and COALL-treated t(12;21)-positive ALL.

Striking facial dysmorphisms and restricted thymic development in a fetus with a 6-megabase deletion of chromosome 14q.

During routine ultrasound screening at 12 weeks 5 days of gestation, a nuchal translucency of 7 mm, an omphalocele, and fetal hydrops were found and prompted chorionic villus sampling at 13 weeks 2 days. Chromosome analysis showed an unbalanced karyotype with an abnormal chromosome 14. The mother was a carrier of a translocation karyotype 46,XX,t(13;14) (q34;q32.2). In the fetus this gave rise to a partial trisomy 13q and partial monosomy 14q (fetal karyotype: 46,XX,der[14]t[13;14][q34;q32.2]). By Array-CGH on DNA extracted from a postmortem skin culture, a duplication of approximately 1.7 Mbp of the distal part of chromosome 13q34 and a deletion of approximately 6.0 Mbp of the distal part of chromosome 14q32.2 was demonstrated. Postmortem findings after termination of pregnancy at 14 weeks 6 days included, among others, a severe hypoplasia of the median part of the maxilla, no recognizable nose, a broad median palatoschisis, nonlobulated lungs, a horseshoe kidney with multicystic dysplasia, and decreased development of cortical cellularity in the thymus. These clinical manifestations and autopsy findings of the fetus are compared with those of previously published cases and the possible involvement in this pathology of the YY1 and JAG2 transcription factors and the BCL11b and SIVA-1 regulators of thymic development is discussed.

Congenital renal tract anomalies: outcome and follow-up of 402 cases detected antenatally between 1986 and 2001.

OBJECTIVE: To determine the long-term prognosis of antenatally detected renal tract anomalies in order to optimize parental counseling. METHODS: This was a follow-up study of all renal tract abnormalities detected antenatally in a Level 3 ultrasound department between 1986 and 2001. Follow-up data (median age, 8 years) were retrieved from the records of the Paediatric Urology Department or the attending pediatrician. RESULTS: A urinary tract anomaly was detected in 408 fetuses. There were four false-positive diagnoses. From two children follow-up data were incomplete, leaving 402 cases for analysis. A chromosomal abnormality was present in 7/81 (8.6%) fetuses that had karyotyping. Termination of pregnancy was performed in 55 (13.7%) cases and a further 66 (16.4%) children died during the perinatal period and up to 1 year of age. In 106/121 (26.4% of all fetuses) deceased children the cause of death was directly related to the renal tract anomaly. In the 281 surviving children a total of 545 renal tract anomalies were diagnosed postnatally, requiring a total of 381 surgical interventions in 156 infants. Outcome in survivors was generally good, with impaired renal function in nine infants and hypertension in three (4% of the survivors). CONCLUSIONS: Congenital renal tract anomalies are associated with a high mortality rate, especially when they are structural developmental anomalies of the kidneys. Survivors require multiple operations, but the outcome is generally favorable. Ultrasound diagnosis, especially when made early, of non-lethal urinary tract anomalies may prevent additional renal damage by timing of delivery and early postnatal treatment.

Variability in dilatation of the fetal renal pelvis during a bladder filling cycle.

OBJECTIVE: To investigate the variation in the dimensions of the fetal renal pelvis in relation to the degree of bladder filling in fetuses with mild pyelectasis. METHODS: Eighteen third-trimester pregnant women with mild uni- or bilateral fetal pyelectasis, defined as an anteroposterior (A-P) diameter of the renal pelvis between 5 and 10 mm, were recruited for the study. The women were examined for 2-3 h by ultrasound. The A-P and transverse dilatation of the renal pelvis and the bladder dimensions (to calculate fetal bladder volume) were measured at 2-3-min intervals. Postnatally, all infants were investigated by ultrasound at 3-4 months. RESULTS: In 6/18 fetuses a consistent relationship between the size of the renal pelvis and bladder filling was found, with a mean difference in renal pelvic diameter before and after voiding of 6.7 mm and a largest observed difference of 14.3 mm. In 12/18 fetuses no such relationship was found. Postnatally, five infants were referred to a pediatric urologist. The investigations in these five infants could not confirm the hypothesis that variation in renal pelvic size in relation to bladder size may predict prenatal vesicoureteric reflux (VUR). CONCLUSIONS: In mild pyelectasis the size of the renal pelvis is highly variable in one-third of cases. The association with bladder volume and micturition suggests evidence of VUR, but this could not be proven. If cut-off values are used to differentiate between normal and abnormal renal pelvic size then not only gestational age but also the degree of bladder filling at the time of measurement should be taken into account. Caution should be expressed when the diagnosis of a possible urological anomaly is based on a single measurement during just one investigation.

Effect of antenatal glucocorticoid therapy on arterial and venous blood flow velocity waveforms in severely growth-restricted fetuses.

OBJECTIVE: To study the effects of antenatal glucocorticoid (betamethasone) therapy on blood flow velocity waveform patterns in the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV) in severely intrauterine growth-restricted (IUGR) fetuses. METHODS: Fifty-five severely IUGR fetuses at 24-34 weeks of gestation were included in the study. The effect of antenatal glucocorticoid administration on Doppler findings in the UA, MCA and DV was studied using two statistical approaches, namely paired sample analysis and multilevel analysis. RESULTS: There were no effects of betamethasone on the pulsatility index (PI) of the vessels studied. The only changes noticed during the 14 days of observation were a gradual decrease of PI in the MCA, an increase in the UA-PI/MCA-PI ratio and an increase in the DV-PI. These changes with time may be explained by a progressive and gradual deterioration of the fetal condition. CONCLUSION: Antenatal glucocorticoids (betamethasone) do not affect fetal Doppler waveform patterns of the UA, MCA and DV in severely IUGR fetuses.

Relationship between monitoring parameters and perinatal outcome in severe, early intrauterine growth restriction.

OBJECTIVE: To investigate whether pathological changes in the umbilical artery (UA), ductus venosus (DV) and short-term fetal heart variation are related to perinatal outcome in severe, early intrauterine growth restriction (IUGR). METHODS: This multicenter, prospective, longitudinal, observational study was carried out in the Departments of Fetal Medicine and Obstetrics in Hamburg, Amsterdam, Utrecht and London. In 70 singleton pregnancies with IUGR fetuses, delivered at 26-33 weeks of gestation because of antepartum fetal distress, short-term variation (STV) of fetal heart rate, pulsatility index of the fetal UA (UA PI) and DV pulsatility index for veins (DV PIV) were assessed at least weekly. The final measurement was performed within 24 h of delivery. Standard cut-off levels (2 SD or 3 SD, absent flow or reversed flow) were used and new cut-off levels were calculated by means of receiver-operating characteristics analysis. Adverse outcome was defined as perinatal death, cerebral hemorrhage (> or = Grade II) or bronchopulmonary dysplasia before discharge. The predictive value for adverse outcome was calculated for different cut-off levels of the monitoring parameters, adjusted for gestational age (GA), by multivariate logistic regression analysis. Data were analyzed separately for three different time blocks, namely 8-14, 2-7 and 0-1 days before delivery. RESULTS: Adverse perinatal outcome occurred in 18/70 (26%) infants. During the last 24 h before delivery DV PIV and UA PI were significantly higher and STV lower in the adverse outcome group, while 2-7 days before delivery only DV PIV was significantly higher. Adverse perinatal outcome could be predicted at 0-1 days before delivery by DV PIV at a cut-off of three multiples of the SD (odds ratio (OR) 11.3; 95% CI 2.3-57) and GA (OR 0.4; 95% CI 0.3-0.8), at 2-7 days by DV PIV at 2 SD (OR 3.0; 95% CI 0.8-12) and GA (OR 0.5; 95% CI 0.3-0.8) and at 8-14 days by DV PIV at 2 SD (OR 3.9; 95% CI 0.8-20) and GA (OR 0.5; 95% CI 0.3-0.8). Other parameters did not contribute to the multivariate model. CONCLUSIONS: DV PIV measurement is the best predictor of perinatal outcome. This measurement may be useful in timing the delivery of early IUGR fetuses and in improving perinatal outcome, even when delivery may be indicated at an earlier GA. However, as GA was also an important factor influencing outcome, with poorer outcome at earlier gestation at delivery, this hypothesis needs to be tested in a multicenter, prospective, randomized trial.

The amniotic fluid index in late pregnancy.

OBJECTIVE: Our purpose was to examine changes in the amniotic fluid index (AFI) in accurately dated term pregnancies both in relation to gestational age and in relation to the onset of spontaneous labor. STUDY DESIGN: This was a prospective observational study in 137 women with uneventful term pregnancies, in whom 220 AFI measurements were performed. More than one AFI value was available from 51 individuals. RESULTS: The AFI did not change significantly between 37 and 42 weeks' gestation, but a significant reduction was seen during the last 11 days before the spontaneous onset of labor (R = -0.37, n = 83, p < 0.001). The AFI (corrected for gestational age) within individuals remained stable over periods of up to 2 weeks. Meconium staining of the amniotic fluid was related to gestational age, but not to the AFI or fetal distress at birth. No significant correlation was found between fetal distress and the AFI, or between fetal distress and the reduction in AFI during the last two measurements before labor. CONCLUSIONS: The reduction of the AFI in pregnancies progressing beyond term is related to the labor process itself rather than to the exact gestational age.

Doppler studies on the fetal renal artery in the severely growth-restricted fetus.

OBJECTIVES: To examine changes with time in the fetal renal circulation by Doppler sonography in the severely growth-restricted preterm fetus during the period of gradual deterioration prior to delivery, and to examine the relationship between Doppler measurements, amniotic fluid index, birth weight and fetal condition at birth. METHODS: This was a prospective observational study in 16 preterm growth-restricted fetuses between 26 and 35 weeks of gestational age. Serial Doppler measurements were made of the renal artery, umbilical artery, middle cerebral artery and ductus venosus. RESULTS: The pulsatility index in the renal artery did not show any correlation with cord blood pH, birth weight or amniotic fluid index corrected for gestational age (Delta/SDAFI). However, peak systolic velocities in the renal artery showed a significant reduction with time (n = 7, P < 0.05) and a significant correlation with: venous cord pH at delivery (n = 12, r = 0.84, P < 0.001), Delta/SDAFI (n = 16, r = 0.67, P < 0.01), and birth weight (n = 16, r = 0.61, P < 0.02). Birth weight correlated significantly with: Delta/SDAFI (n = 15, r = 0.57, P < 0.05), pulsatility index values of the middle cerebral artery (n = 15, r = -0.61, P < 0.02), and pulsatility index values of the ductus venosus (n = 16, r = 0.55, P < 0.05), and Delta/SDAFI correlated significantly with: pulsatility index values of the ductus venosus (n = 15, r = 0.51, P < 0.05) and arterial cord pH values at delivery (n = 8, r = 0.78, P < 0.05). CONCLUSIONS: Progressive redistribution of the circulation occurs with deterioration of the fetal condition in the growth-restricted preterm fetus. On spectral Doppler this is reflected by changes in peak systolic velocities, but not by changes in pulsatility values of the fetal renal artery waveforms.

Schneckenbecken dysplasia, radiology, and histology.

To our knowledge this is the first report of Schneckenbecken dysplasia with the development of hydrops early in the second trimester. The radiological findings showed the typical hypoplastic iliac bones with medial extension and very flattened, on lateral view, oval-shaped vertebral bodies and short long bones. The histology showed hypercellular and hypervascular cartilage with chondrocytes with centrally located nucleus. The absence of the lacunar space as described before was also observed in some chondrocytes in our case. This male fetus was the product of consanguineous parents of Mediterranean origin compatible with autosomal recessive inheritance.

Monitoring of fetuses with intrauterine growth restriction: a longitudinal study.

OBJECTIVE: To describe the time sequence of changes in fetal monitoring variables in intrauterine growth restriction and to correlate these findings with fetal outcome at delivery. METHODS: This was a prospective longitudinal observational multicenter study on 110 singleton pregnancies with growth-restricted fetuses after 24 weeks of gestation. Short-term variation of fetal heart rate, pulsatility indices of fetal arterial and venous Doppler waveforms and amniotic fluid index were assessed at each monitoring session. The study population was divided into two groups: Group 1 comprised pregnancies with severely premature fetuses, which were delivered < or =32 weeks and Group 2 included pregnancies delivered after 32 completed weeks. Logistic regression was used for modeling the probability for abnormality of a variable in relation to the time interval before delivery. Trends over time were analyzed for all variables by multilevel analysis. RESULTS: Ninety-three (60 in Group 1 and 33 in Group 2) fetuses had at least three data sets (median, 4; range, 3-27) and had the last measurements taken within 24 h of delivery or intrauterine death. The percentage of abnormal test results and the degree of abnormality were higher in Group 1 compared to Group 2. Amniotic fluid index and umbilical artery pulsatility index were the first variables to become abnormal, followed by the middle cerebral artery, aorta, short-term variation, ductus venosus and inferior vena cava. In Group 1, short-term variation and ductus venosus pulsatility index showed mirror images of each other in their trend over time. Perinatal mortality was significantly higher if both variables were abnormal compared to only one or neither being abnormal (13/33 (39%) vs. 4/60 (7%); P = 0.0002; Fisher's exact test). CONCLUSION: Ductus venosus pulsatility index and short-term variation of fetal heart rate are important indicators for the optimal timing of delivery before 32 weeks of gestation. Delivery should be considered if one of these parameters becomes persistently abnormal.

Precarious acrocentric short arm in prenatal diagnosis: no chromosome 14 polymorphism, but trisomy 17p.

Precarious acrocentric short arm in prenatal diagnosis: no chromosome 14 polymorphism, but trisomy 17p: We report on a girl with multiple congenital abnormalities and a prenatally diagnosed 46,XX,14p+ de novo karyotype. Fluorescence in situ hybridization (FISH) demonstrated that the extra material on the short arm of chromosome 14 was not just a polymorphism, but that it originated from chromosome 17. The phenotypic findings of this patient with pure trisomy 17p are compared with those of ten previously published cases.

Hourly fetal urine production rate in the near-term fetus: is it really increased during fetal quiet sleep?

Fetal bladder volume and hourly fetal urine production (HFUPR) is calculated on the assumption that the fetal bladder is ellipsoid in shape. A recent validation study demonstrated a progressive overestimation at increasing bladder volumes. This may be due to changes in shape of the fetal bladder at increasing volumes. Two independent papers have shown increased HFUPR during fetal behavioural state 1F (S1F) when compared with S2F. The aim of the present study was to assess whether this increase of HFUPR during S1F, previously observed by others, could be the result of an error introduced by the method of volume calculation. A retrospective evaluation was performed in a series of 208 HFUPR measurements in 123 normal near term pregnant women attending a low-risk atenatal clinic. Adequate bladder filling in both states was identified in 43 recordings. Maximum fetal bladder volumes were greater (> 10 ml) during S1F in comparison to S2F in 56% of these recordings and HFUPR was significantly greater during S1F only in these cases. Bladder volumes are usually lower during S2F as a result of fetal voiding, which occurred in association with 22 of 36 transitions from S1F to S2F, and only 1 of 13 transitions from S2F to S1F (P < 0.001). When disregarding calculated bladder volumes in excess of 20 ml for the purpose of calculating HFUPR, eleven recordings remained. HFUPR calculated in this way was significantly lower in comparison to measurements where larger bladder volumes were included and no difference was observed between states. This implies that the differences observed are the result of the greater error in calculating bladder volumes and HFUPR during S1F, where volumes are usually greater and that calculation of fetal bladder volume should not be performed on the assumption that the bladder is ellipsoid in shape. Alternative techniques include limiting measurements to a maximum volume of approximately 20 ml, when the bladder is usually ellipsoid in shape or basing volume calculation on the surface area of a series of sagittal views as suggested by Hedriana and Moore [Hedriana HL, Moore TR. Ultrasonographic evaluation of human fetal urinary flow rate: accuracy of bladder volume estimations. Am J Obstet Gynecol 1994;170:1250-1254; Hedriana HL, Moore TR. Accuracy limits of ultrasonographic estimation of fetal urinary flow rate.