Measurement of fetal urine production to differentiate causes of increased amniotic fluid volume

OBJECTIVES

In polyhydramnios, amniotic fluid (AF) volume can be increased not only as a result of increased fetal urine production, but also due to several other factors, including impairment of both fetal swallowing and gastrointestinal (GI) absorption of AF. Our aim was to evaluate whether measurement of the fetal urine production rate (UPR) can be used to differentiate the causes of increased AF volume.

METHODS

This cross-sectional study included 54 pregnant women with an increased amniotic fluid index (AFI), defined as AFI > or = 18 cm, divided into two groups according to the presence of fetal anomalies that are associated with impairment of fetal swallowing or decreased GI absorption of AF (Group 1, n = 14) or the absence of fetal anomalies (Group 2, n = 40). The control group included 96 normal pregnancies with normal AFI (8 < or = AFI < 18 cm) (Group 3). Fetal UPR was obtained by serial bladder volume measurements (two to four times, with a median interval of 5 min between each) using the rotational method of Virtual Organ Computer-aided AnaLysis (VOCAL()) with three-dimensional ultrasound. To adjust for fetal weight (Wt) and gestational age (GA), UPR_Wt and UPR_SD were calculated using the following formulae: UPR_Wt = measured UPR/estimated fetal weight and UPR_SD = (measured UPR - mean UPR for each GA)/SD of UPR for each GA.

RESULTS

The AFI was increased significantly in Groups 1 and 2 compared with Group 3. However, the median fetal UPR in Group 1 did not differ from that of Group 3, in contrast to the higher median fetal UPR in Group 2 compared with Groups 1 and 3; this difference remained significant after adjusting for GA and estimated fetal weight in terms of UPR_SD and UPR_Wt. In Groups 2 and 3, AFI and UPR had a positive correlation in terms of UPR, UPR_SD and UPR_Wt.

CONCLUSIONS

Our findings that fetal UPR is significantly increased in cases with increased AFI without fetal anomalies, but not in those with increased AFI and fetal anomalies involving decreased GI absorption of AF, might be used to differentiate causes of increased AF volume. In the absence of fetal anomalies, AFI and fetal UPR correlate positively.

Expression of extracellular signal-regulated kinase1/2 and p38 mitogen-activated protein kinase in the invasive trophoblasts at the human placental bed

BACKGROUND

Mitogen-activated protein kinases (MAP kinases) participate in signal transduction pathways that control embryogenesis, cell differentiation, cell proliferation and cell death. The roles of extracellular signal-regulated kinase1/2 (ERK1/2) and p38 MAP kinase in the differentiation and invasion of human trophoblasts have been studied. However, the in vivo expression and activation of ERK1/2 and p38 at the placental bed have not been elucidated.

METHODS

The study group consisted of placental bed biopsy tissues obtained from the pregnancies without preeclampsia (n=24) and with preeclampsia (n=8) between 31 and 40 weeks of gestation. We evaluated the expressions and phosphorylations of ERK1/2 and p38 MAP kinase in the invasive trophoblasts in the placental bed tissues using immunohistochemistry.

RESULTS

p38 and phospho-p38 MAP kinase were not detected in invasive trophoblasts in cases or controls. ERK1/2 and phospho-ERK1/2 were positive in invasive trophoblasts albeit with variable staining. Phosphorylation of ERK1/2 was significantly less frequent in invasive trophoblasts in placental bed biopsies from women with preeclampsia compared with normotensive controls.

CONCLUSION

These findings suggest that preeclampsia is associated with decreased activation of ERK1/2 in invasive trophoblasts in vivo.

Measurement of fetal urine production by three-dimensional ultrasonography in normal pregnancy

OBJECTIVES

Measurement of fetal urine production may provide a means of evaluating amniotic fluid volume, which is difficult to measure directly, and predicting fetal hypoxia. Although there have been some reports on fetal urine production, most of these have used two-dimensional (2D) ultrasonography to measure bladder volume. Three-dimensional (3D) ultrasonography is, however, known to be superior to 2D ultrasonography in some organ volume measurements. Thus, we undertook this study to measure bladder volumes using 3D ultrasonography and to establish a nomogram of fetal urine production rate (UPR) according to gestational age (GA).

METHODS

One hundred and fifty-four women with a normal singleton pregnancy at 24 to 40 weeks' gestation were enrolled in this cross-sectional study. The women had no medical or obstetric complications affecting amniotic fluid volume. Fetal bladder volume was measured using 3D ultrasound imaging and Virtual Organ Computer-aided AnaLysis (VOCAL) with a rotational angle of 30 degrees and manual surface tracing technique. Bladder volume was measured two or three times within a 5-10-min interval and fetal UPR was calculated from serial measurements. When measurements were performed more than twice, we used the mean rate of calculated UPRs. UPR was then plotted against GA to establish the nomogram.

RESULTS

Fetal UPR increased with GA from a median value of 7.3 mL/h at 24 weeks' gestation to 71.4 mL/h at term, and could be calculated from GA using the formula: Ln(UPR) = - 6.29582 + (0.43924 x GA) + (0.000432 x GA2), r2 = 0.63, P = 0.0046. Growth percentiles of UPR according to age are presented.

CONCLUSIONS

Fetal UPR can be easily measured by 3D ultrasound assessment of bladder volume. This modality may be a promising alternative to conventional methods of amniotic fluid volume measurement such as amniotic fluid index and single deepest pocket, and might be an alternative option for predicting fetal hypoxia.

High expression of tumor necrosis factor-alpha and interleukin-6 in periventricular leukomalacia

OBJECTIVE

Periventricular leukomalacia, a common neonatal brain white matter lesion, is a major risk factor for cerebral palsy. Subclinical chorioamnionitis is a risk factor for the development of periventricular leukomalacia, and inflammatory cytokines have been implicated as central mediators of brain injury in this disorder. To elucidate the relationship between the local expression of cytokines and periventricular leukomalacia, we studied neonatal brains to determine whether high expression of tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 was observed in these lesions.

STUDY DESIGN

Immunohistochemical staining for cytokines (tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6) was performed in 10% formalin-fixed, paraffin-embedded brain sections of 17 cases with periventricular leukomalacia. Specimens were obtained from autopsies performed between 1987 and 1994. Brain sections from 17 cases of neonatal deaths without periventricular leukomalacia lesions matched for gestational age at birth, duration of postnatal survival, and presence or absence of infection-related morbidity were used as controls.

RESULTS

The expression of tumor necrosis factor-alpha, interleukin-1 beta, or interleukin-6 was demonstrated in 88% (15/17) of cases with and in 18% (3/17) of cases without periventricular leukomalacia (p < 0.001). Cytokines were expressed mainly in hypertrophic astrocytes and microglial cells. The expression of tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 was identified in 82% (14/17), 29% (5/17), and 71% (12/17) of cases of periventricular leukomalacia, respectively. However, a significantly lower proportion of cases without periventricular leukomalacia expressed tumor necrosis factor-alpha (18%, 3/17) and interleukin-6 (6%, 1/17) than those with the disorder (p < 0.005 for each).

CONCLUSIONS

Expression of tumor necrosis factor-alpha and interleukin-6 was observed more frequently in brain lesions with periventricular leukomalacia than in those without periventricular leukomalacia. These findings provide strong support for the hypothesis that proinflammatory cytokines play a role in the genesis of periventricular leukomalacia.

Serum C-reactive protein, white blood cell count, and amniotic fluid white blood cell count in women with preterm premature rupture of membranes

OBJECTIVE

To compare the diagnostic performance of maternal blood C-reactive protein, white blood cell count (WBC), and amniotic fluid (AF) WBC in the identification of positive AF culture, histologic and clinical chorioamnionitis, and neonatal morbidity in women with preterm premature rupture of membranes (PROM).

METHODS

Maternal blood was collected for the determination of C-reactive protein and WBC at the time of amniocentesis from 90 women with preterm PROM. Amniotic fluid was cultured for aerobic and anaerobic bacteria as well as mycoplasmas. Amniotic fluid WBC was determined for research purposes. Receiver operating characteristic curve and logistic regression were used for statistical analysis.

RESULTS

The prevalence of positive AF culture was 28% (25 of 90). Women with positive AF culture and clinical chorioamnionitis had significantly higher median C-reactive protein, WBC, and AF WBC than did women without these conditions (P < .05), whereas women with histologic chorioamnionitis and significant neonatal morbidity had higher median C-reactive protein and AF WBC, but not WBC, than those without the conditions (P < .05). An AF WBC of at least 20 cells per mm3 had a greater sensitivity than C-reactive protein (cutoff, 0.7 mg/dL) and WBC (cutoff, 13,000 cells per mm3) in the detection of positive AF culture and histologic chorioamnionitis. Logistic regression analysis indicated that among AF WBC, C-reactive protein, and WBC, AF WBC was the best predictor of positive AF culture (odds ratio [OR] 24.2, 95% confidence interval [CI] 6.0, 97.5, P < .001), histologic (OR 74.0, 95% CI 7.4, 736.3, P < .001) and clinical chorioamnionitis (OR 8.9, 95% CI 0.9, 85.6, P = .057), and neonatal morbidity (OR 4.3, 95% CI 1.1, 16.6, P < .05).

CONCLUSION

Amniotic fluid WBC performs better than C-reactive protein and maternal blood WBC in the diagnosis of positive AF culture, histologic and clinical chorioamnionitis, and neonatal morbidity in women with preterm PROM.

Interleukin-6 concentrations in umbilical cord plasma are elevated in neonates with white matter lesions associated with periventricular leukomalacia

OBJECTIVE

Periventricular leukomalacia, a common brain white matter lesion in preterm neonates, is a major risk factor for cerebral palsy. Recently, cytokines (i.e., tumor necrosis factor and interleukin-1(beta)) have been implicated as mediators for the development of periventricular leukomalacia. The purpose of this study was to examine the relationship between umbilical cord plasma levels of tumor necrosis factor-alpha, interleukin-1(beta), interleukin-6, and interleukin-1 receptor antagonist and the occurrence of periventricular leukomalacia in preterm neonates.

STUDY DESIGN

Umbilical cord blood was collected from 172 consecutive preterm births (25 to 36 weeks). Periventricular leukomalacia-associated lesions were diagnosed by brain ultrasonography within the first 3 days of life. Tumor necrosis factor-alpha, interleukin-1(beta) interleukin-6, and interleukin-1 receptor antagonist were measured by sensitive and specific enzyme-linked immunoassay methods. Umbilical cord arterial pH was measured at birth. Statistical analysis was performed with multiple logistic regression and receiver operating characteristic curve analysis.

RESULTS

Periventricular leukomalacia-associated lesions were present in 14.5% (25/172) of infants. Plasma concentrations of interleukin-6 but not of tumor necrosis factor-alpha, interleukin-1(beta), and interleukin-1 receptor antagonist were significantly higher in neonates with periventricular leukomalacia-associated lesions than in those without these lesions (median 718, range < 226 to 32,000 pg/ml vs median < 226, range < 226 to 43,670 pg/ml; p < 0.0001). An interleukin-6 value > or = 400 pg/ml had a sensitivity of 72% (18/25) and a specificity of 74% (108/147) in the identification of periventricular leukomalacia-associated lesions. Multivariate analysis showed that umbilical cord interleukin-6 was an independent risk factor for periventricular leukomalacia (odds ratio 6.2, p < 0.002) after correction for known confounding variables (i.e., gestational age at birth, umbilical artery pH, chorioamnionitis).

CONCLUSIONS

Interleukin-6 concentrations in umbilical cord plasma are elevated in neonates with periventricular leukomalacia-associated lesions. Our data support the hypothesis that periventricular leukomalacia may be the result of cytokine-mediated brain injury.

Amniotic fluid interleukin-6: a sensitive test for antenatal diagnosis of acute inflammatory lesions of preterm placenta and prediction of perinatal morbidity

OBJECTIVE

Our purpose was to determine whether amniotic fluid concentrations of interleukin-6 are of value in the antenatal diagnosis of acute inflammatory lesions (histologic chorioamnionitis) of preterm placenta and in the prediction of perinatal morbidity and mortality.

STUDY DESIGN

The relation among placental histologic findings, perinatal outcome, and amniotic fluid interleukin-6 concentrations was examined in 50 consecutive patients who delivered preterm neonates within 72 hours after amniocentesis. Interleukin-6 was determined by enzyme-linked immunosorbent assays. Receiver-operator characteristic curve was used for analysis.

RESULTS

Patients with acute histologic chorioamnionitis had significantly higher median amniotic fluid interleukin-6 concentrations than patients without histologic chorioamnionitis (median 70.8 ng/ml, range 0.7 to 499.2 ng/ml vs median 2.9 ng/ml, range 0.8 to 16.0 ng/ml, respectively; p < 0.00001). An amniotic fluid interleukin-6 concentration > 17 ng/ml had a sensitivity of 79% (23/29) and a specificity of 100% (21/21) in the diagnosis of acute histologic chorioamnionitis and a sensitivity of 69% (18/26) and a specificity of 79% (19/24) in the prediction of significant neonatal morbidity (defined as neonatal sepsis, respiratory distress syndrome, pneumonia, intraventricular hemorrhage, bronchopulmonary dysplasia, or necrotizing enterocolitis) and mortality. These sensitivities were significantly higher than those of amniotic fluid culture (79% vs 38%, p < 0.005; 69% vs 27%, p < 0.01, respectively).

CONCLUSIONS

Amniotic fluid interleukin-6 is a sensitive test for the prospective diagnosis of acute histologic chorioamnionitis and the identification of neonates at risk for significant morbidity and mortality.

Relationship between the fetal biophysical profile score, umbilical artery Doppler velocimetry, and fetal blood acid-base status determined by cordocentesis

OBJECTIVE

Fetal hypoxia-acidosis is part of the terminal pathway leading to intrauterine fetal death. A central premise of antepartum surveillance is that identification and timely delivery of the hypoxic or acidotic fetus will prevent intrauterine death and decrease long-term neurologic damage. The optimal method to identify fetal hypoxia-acidosis has not been determined. We attempted to compare the performance of the biophysical profile score and umbilical artery Doppler velocimetry in the identification of fetal acidemia, hypoxemia, and hypercarbia as determined by pH and gas analysis of fetal blood obtained by cordocentesis.

STUDY DESIGN

Fetal biophysical profile and umbilical artery Doppler velocimetry studies were performed before cordocentesis in 24 patients (26 to 40 weeks). Umbilical vein pH and blood gas values were determined in all cases. The pulsatility index of the umbilical artery was obtained with pulsed Doppler equipment. Receiver-operator characteristic curve analysis and stepwise multiple logistic regression were performed to examine the relationship between biophysical profile score, umbilical artery Doppler velocimetry, and acid-base status.

RESULTS

The prevalence of fetal acidemia (pH 2 SD below the mean for gestational age) was 41.7% (10/24). There was a significant relationship between the change in umbilical artery pulsatility index and fetal acidemia (chi 2 = 26.6, p < 0.001) and hypercarbia (chi 2 = 22.9, p < 0.001), but not hypoxemia (chi 2 = 1.0, p > 0.1), and between the biophysical profile score and fetal acidemia (chi 2 = 11.1, p < 0.001) and hypercarbia (chi 2 = 9.0, p < 0.005), but not hypoxemia (chi 2 = 2.3, p > 0.1). Stepwise multiple logistic regression demonstrated that umbilical artery Doppler velocimetry was a better explanatory variable for acidemia and hypercarbia than the biophysical profile score.

CONCLUSION

A strong relationship between the degree of fetal acidemia and hypercarbia and the results of umbilical artery Doppler velocimetry and biophysical profile was found. However, umbilical artery Doppler velocimetry was a better explanatory variable for these outcome than the biophysical profile score.

Is an abnormal Doppler umbilical artery waveform ratio a risk factor for poor perinatal outcome in the non-small for gestational age fetus?

To determine if abnormal umbilical artery velocimetry is associated with a higher rate of perinatal morbidity in pregnancies in which the outcome is not manifested by a small for gestational age (SGA) fetus, perinatal outcome was compared according to the results of Doppler umbilical artery velocimetry. Doppler study was performed in 328 singleton pregnancies with non-SGA fetuses within 7 days of delivery. The prevalence of abnormal Doppler studies was 10%. Patients with abnormal umbilical artery velocimetry had a significantly higher rate of complications, including cesarean section for fetal distress, preterm delivery, low Apgar scores, congenital anomalies, admission to the neonatal intensive care unit, and perinatal death, than patients with a normal umbilical artery velocimetry. Ten perinatal deaths were associated with major congenital anomalies. Moreover, in the absence of congenital anomalies patients with abnormal Doppler results also had a significantly higher incidence of adverse perinatal outcome compared with patients with normal umbilical artery velocimetry. Our data suggest that even the non-SGA fetus with an abnormal Doppler umbilical artery waveform ratio is at increased risk for poor perinatal outcome.