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PubMed1992

Does amniotic fluid analysis reflect acid-base balance in fetal blood?

OBJECTIVE: The purpose of the study was to examine whether the acid-base balance in amniotic fluid reflects the acid-base state in fetal blood. STUDY DESIGN: The pH, PCO2, PO2, bicarbonate, and base excess concentrations were measured in umbilical venous, umbilical arterial, and maternal venous blood and in amniotic fluid samples obtained at fetoscopy. This was performed before intraamniotic termination of 16 normal pregnancies (mean gestation 19.4 weeks), as well as in 14 red blood cell isoimmunized pregnancies (mean gestation 28.4 weeks) undergoing fetoscopy for the diagnosis and treatment of fetal anemia. RESULTS: In normal pregnancies, amniotic fluid pH and bicarbonate were significantly lower than umbilical venous and umbilical arterial blood concentrations, and this was due to the high concentration of base deficit in amniotic fluid. Whereas amniotic fluid PCO2 did correlate significantly with fetal umbilical venous PCO2 values, there was no correlation between other acid-base characteristics. CONCLUSION: Simultaneous sampling of human fetal umbilical blood and amniotic fluid under the acute conditions of this study did not show significant correlations in acid-base values.

Acid-Base Equilibrium↗
PubMedDate not supplied

Elevated concentrations of prorenin and renin in amniotic fluid of women with chorioamnionitis.

OBJECTIVE: The objective of this study was to determine the concentrations of prorenin and renin in amniotic fluid of women under various physiologic and pathologic conditions. METHODS: Amniotic fluid was collected from women with chorioamnionitis treated in the Labor and Delivery Unit, University of Utah Medical Center, and from gestation-matched control women with preterm labor who were delivered within 1 week and later than 1 week and at term in labor or not in labor. Prorenin and renin concentrations were measured in these fluids by a direct immunoradiometric assay. RESULTS: Large amounts of prorenin and renin were detected in all samples with 85% to 95% in the form of prorenin. Concentrations of both prorenin and renin were significantly higher in the amniotic fluid of women with chorioamnionitis than in the amniotic fluid of control women. There were no other significant differences between the groups. CONCLUSIONS: Our data indicate that amniotic fluid concentrations of renin and prorenin are elevated in women with clinically evident chorioamnionitis. We suggest that these elevations reflect a possible role for renin and prorenin in the pathophysiologic process of intrauterine infection-associated preterm labor.

Amniotic Fluid↗
PubMed2001

Production of secretory leukocyte protease inhibitor by human amniotic membranes and regulation of its concentration in amniotic fluid.

Secretory leukocyte protease inhibitor (SLPI) is a potent inhibitor of human leukocyte elastase. SLPI is a protein found in various human fluids, including parotid secretions, cervical mucus, seminal plasma and ascites. Western blot analysis revealed that SLPI protein is detected as a 12 kDa band in both the amniotic fluid and the amniotic membrane. The amniotic fluid concentrations of SLPI were assayed by enzyme-linked immunosorbent assay. SLPI concentrations in the amniotic fluid of women in the third trimester were higher than those in the second trimester. Immunohistochemistry using an anti-SLPI polyclonal antibody revealed positive staining in epithelial cells in amniotic membranes. Reverse transcription-polymerase chain reaction demonstrated that SLPI transcripts could be detected in the amniotic membranes. To determine the mechanism of SLPI production by amniotic cells, purified amniotic cells were stimulated with various cytokines. Amniotic cells produced SLPI in a dose-dependent manner when stimulated with interleukin (IL)-1alpha, IL-1beta, and tumour necrosis factor-alpha. The present findings show that SLPI is produced by the amniotic membranes in response to cytokine concentrations. The SLPI in the amniotic fluid may contribute to immunodefence mechanisms during pregnancy.

Amniotic Fluid↗
PubMed1977

Significance of amniotic fluid corticosteroid levels in human pregnancies.

Retrospective analysis of 103 samples of amniotic fluid was performed. Twenty-four samples were obtained prior to midtrimester abortion, 31 were from patients who delivered spontaneously, 14 were from patients in whom labor was induced, and the remaining samples were obtained from patients who were delivered by cesarean section. In all normal pregnancies, there was a rising trend in corticosteroid levels in amniotic fluid as the gestation advanced. This was less marked in abnormal pregnancies. There is a suggestive fetal role in initiation of normal spontaneous labor, as reflected by a significant increase in amniotic fluid corticosteroid levels, in patients immediately prior to vaginal delivery as opposed to abdominal delivery. There was a significant correlation between the birthweight of babies born vaginally with the amniotic fluid corticosteroid levels, as compared to the weight of babies born by cesarean section.

Adrenal Cortex Hormones↗
PubMed2004

On the origin of amniotic fluid bilirubin.

We studied the relationship between bilirubin concentrations in amniotic fluid and fetal blood in 68 non-hydropic rhesus d-alloimmunized anemic fetuses at first blood sampling. In these alloimmunized fetuses, the amniotic fluid/fetal blood ratio for bilirubin decreased from 0.09 at 28 weeks to 0.05 at 33 weeks. In normal fetuses, amniotic fluid/fetal blood ratios for bilirubin, and for albumin, are in the same range and show a similar decrease during gestation. We conclude that amniotic fluid bilirubin concentration is determined, firstly, by fetal blood bilirubin concentration and, secondly, by the amniotic fluid/fetal blood ratio of albumin. Among five possible pathways bilirubin could take to build up a concentration in amniotic fluid (fetal kidneys, lungs, skin, bowel, membranes), the intramembranous pathway is the only one that is compatible with the amniotic fluid/fetal blood ratios for bilirubin that we found and must therefore be the most important.

Amniotic Fluid↗
PubMed2005

Amniotic fluid index measurements in normal pregnancy after 28 gestational weeks.

OBJECTIVE: The purpose of this study is to establish a normative scale of amniotic fluid index (AFI) or four-quadrant amniotic fluid index throughout gestation in uncomplicated singleton pregnancies, and to identify the lower and upper limits for each gestational week. METHOD: A prospective longitudinal study was used. One hundred seventeen uncomplicated singleton pregnancies were examined every 4 weeks between 28 and 42 week's gestation. The uterine cavity was divided into four quadrants. With the use of linear-array, real-time B-scanning, the vertical diameter of the largest pocket in each quadrant was measured. The amniotic fluid index is the sum of these four quadrants. RESULTS: The amniotic fluid index observations from regression equation curve were stratified in week-specific normative curves. The variation between mean AFI of the total population and the means of the preterm was significantly greater than term pregnancies (P<. 05). The AFI 2.5%, 5%, 10%, 90% 95% and 97.5% limits about the 50th (124 mm) were 68, 81, 90, 135, 144 and 145 mm, respectively, in term gestation. The 5th and 95th percentile serves as lower and upper limits of normal, respectively for 28-42 weeks gestation. CONCLUSIONS: Gestational age-specific values of AFI were established, determining the significant trends of changes in the amniotic fluid volume with gestation. The normogram may have a clinical benefit to accurate, reliable and semiquantitative diagnosis of oligohydramnios and polyhydramnios.

Adult↗
PubMed1990

Elevated folate levels in amniotic fluid after oral supplementation.

During oral supplementation of 5 mg folic acid and 1 microgram vitamin B12, the daily folate levels in plasma, red cells and midtrimester amniotic fluid were significantly higher in ten pregnant women during the 15th-18th week of menstrual age as compared to ten non-supplemented women serving as controls. In the control group as well as in the supplemented group, the folate concentrations in amniotic fluid were found to be lower than in the corresponding maternal plasma and red cells. Of all women investigated there was a significant positive correlation between maternal plasma folate concentrations and amniotic fluid levels (r = 0.72, p less than 0.001) and no correlation between red cell folate concentrations and amniotic fluid levels (r = 0.30, p = 0.22). Oral supplementation of vitamin B12 did not elevate maternal blood concentrations and amniotic fluid levels. Vitamin B12 levels in amniotic fluid in this group and controls were always higher than in plasma. These data suggest that the orally administrated dosages of folic acid unlike those of vitamin B12 augment both plasma, red cells and amniotic fluid levels.

Administration, Oral↗
PubMed1985

Urinary beta 2-microglobulin in full-term newborns: evidence for proximal tubular dysfunction in infants with meconium-stained amniotic fluid.

Urinary concentrations of beta 2-microglobulin (beta 2M) and creatinine were measured in normal term infants and in those born with meconium-stained amniotic fluid. None of the infants or their mothers had conditions known to modify beta 2M excretion. Measurements of beta 2M were made on urines collected by bagging; urines obtained from diapers were not satisfactory. Urinary beta 2M concentrations increased significantly (P less than .02) in the normal infants from the first day (0.36 +/- 0.29 mg/L: n = 29) to the third day (0.60 +/- 0.43 mg/L: n = 21) postpartum. Compared with the normal infants, values for the infants with meconium-stained amniotic fluid were increased significantly on days 1 (1.64 +/- 2.16 mg/L: n = 25: P less than .005) and 3 (2.12 +/- 2.04 mg/L: n = 23: P less than .005). Levels exceeded two standard deviations above the normal mean in 12 of the 26 infants with meconium-stained amniotic fluid on postpartum day 1, and 12 of the 23 infants with meconium-stained amniotic fluid on day 3. Urinary creatinine levels were similar in both the normal infants and those with meconium-stained amniotic fluid. All infants with meconium-stained amniotic fluid with a one-minute Apgar score of 6 or less had an elevated urinary beta 2M concentration. The elevated levels of urinary beta 2M in infants with meconium-stained amniotic fluid indicate the existence of tubular dysfunction, probably mild acute tubular necrosis secondary to hypoxia.

Amniotic Fluid↗
PubMed1998

Amniotic fluid and the umbilical cord: the fetal milieu and lifeline.

Amniotic fluid volume should be routinely assessed in every second and third trimester case. A review of amniotic fluid physiology and techniques for ultrasound evaluation of fluid volume is presented. The causes and significance of oligohydramnios and polyhydramnios are stressed. Umbilical cord abnormalities are often incidently observed at the time of amniotic fluid evaluation. The clinical significance of some common umbilical cord abnormalities such as a two-vessel cord and nuchal cord are discussed. Other, more uncommon entities such as cord mass lesions are also reviewed. Finally, the role of cord Doppler interrogation in determining fetal well-being is discussed.

Amniotic Fluid↗
PubMed2004

Second-trimester amniotic fluid interleukin-10 concentration predicts preterm delivery.

OBJECTIVE: Interleukin-6 (IL-6) is an inflammatory cytokine that has been shown to be elevated in the amniotic fluid of patients with preterm labor. On the other hand, interleukin-10 (IL-10) is an anti-inflammatory cytokine that has been shown to inhibit the synthesis of other cytokines. We hypothesized that amniotic fluid IL-10 in the early second trimester is low in patients who subsequently develop preterm labor, and because of its deficiency, excessive inflammatory responses associated with IL-6 elevation lead to preterm labor and delivery. STUDY DESIGN: Amniotic fluid IL-6 and IL-10 levels were measured in 96 women who underwent genetic amniocentesis between 15 and 23 weeks' gestation. Levels of IL-6 and IL-10 were measured by immunoassay and correlated with demographic and pregnancy outcome information. RESULTS: Fifteen patients delivered at or before 36 weeks and 81 patients delivered after 36 weeks. There was an inverse correlation between amniotic fluid IL-10 concentration and gestational age at delivery. Similarly, an inverse correlation also existed between amniotic fluid IL-6 concentration and gestational age at delivery. CONCLUSIONS: Both IL-10 and IL-6 levels in second-trimester amniotic fluid obtained at the time of genetic amniocentesis appeared to be higher in patients who subsequently developed preterm delivery. Therefore, low amniotic fluid IL-10 production during the second trimester does not seem to be an etiology for preterm labor.

Adult↗
PubMed2001

Neonatal amniotic fluid aspiration syndrome underdiagnosed?

Aspiration of uncontaminated amniotic fluid as a cause of significant respiratory distress in neonates is not well documented. We report a term neonate who presented with severe respiratory distress soon after birth. The diagnosis of amniotic fluid aspiration was confirmed at autopsy. Implications of this diagnosis in the management of neonates with respiratory distress are discussed.

Amniotic Fluid↗
PubMed1993

Detection of fetal cocaine exposure by analysis of amniotic fluid.

OBJECTIVE: To determine whether analysis of amniotic fluid (AF) using solid-phase extraction and high-performance liquid chromatography is useful in detecting fetal exposure to cocaine and its metabolites. METHODS: Amniotic fluid and urine samples were obtained from 23 subjects with documented cocaine abuse during pregnancy and five subjects without a history of cocaine abuse. Urine samples were also collected from all newborns. Urine samples were screened using conventional immunoassay techniques and confirmed with thin-layer chromatography. Using a modified solid-phase extraction procedure, we removed cocaine and its metabolites from all AF samples and from the newborn urine samples in which the initial screening was positive. Subsequently, we analyzed the extracts with high-performance liquid chromatography. RESULTS: Cocaine or benzoylecgonine was detected in 74% of AF samples taken from the 23 known cocaine abusers. In these subjects, conventional maternal and neonatal urine toxicology screens were positive in 61 and 35%, respectively. Concentrations in AF ranged from 400 to greater than 5000 ng/mL for benzoylecgonine and from trace to 250 ng/mL for cocaine. Mean benzoylecgonine recovery from AF was significantly greater than from newborn urine (1800 versus 280 ng/mL, respectively; P < .0001). CONCLUSION: Analysis of AF appears to be useful in detecting gestational cocaine exposure.

Amniotic Fluid↗
PubMed1986

Amniotic fluid embolism and leukotrienes.

Extracts of experimental amniotic fluid embolism from rabbit lungs showed the same biologic activities as leukotrienes and a peak on high-performance liquid chromatography at the same retention time as leukotriene D4. Acute death was prevented by administration of 5-lipoxygenase inhibitor. These results suggest the possibility that leukotrienes contribute to the clinical and pathophysiologic features of amniotic fluid embolism.

Animals↗
PubMed1977

Testosterone and dihydrotestosterone in maternal and cord blood and in amniotic fluid.

Maternal and umbillical arterial and venous plasma and amniotic fluid testosterone (T) and dihydrotestosterone (DHT) were measured by radioimmunoassay. Maternal plasma T was 690 +/- 80 pg. per milliliter (mean +/- S.E.) in early pregnancy (less than 20 weeks) and increased significantly (p = 0.0002) to 1,095 +/- 177 pg. per milliliter in late pregnancy (greater than 20 weeks). DHT was 113.0 +/- 18.8 pg. per milliliter in early pregnancy and 179.8 +/- 30.5 pg. per milliliter in late pregnancy. Both umbilical arterial (UA) and umbilical venous (UV) plasma T were significantly higher in 11 male infants (UA T = 135.6 +/- 16.5 pg. per milliliter; UV T = 227.5 +/- 40.8 pg. per milliliter) than in 12 female infants (UA T = 92.1 +/- 9.7 pg. per milliliter; UV T = 89.6 +/- 12.6 pg. per milliliter) (p = less than 0.05 and less than 0.005, respectively). UV DHT and UA DHT showed no significant difference between male and female neonates. In midtrimester pregnancy, amniotic fluid T (AFT) was 165.2 +/- 15.4 pg. per millitier in pregnancies with a male fetus and was significantly higher (p = less than 0.001) than in pregnancies with a female fetus (mean +/- S.E. = 27.6 +/- 2.6 pg. per millitier). In late pregnancy, AFT levels were similar to those of early pregnancy, but a considerable overlap in AFT between fetuses of both sexes was observed. DHT was not detectable in amniotic fluid. The results suggest the potential value of AFT for determining fetal sex in midtrimester pregnancy and confirm that maternal T and DHT increase during pregnancy and that cord T levels reflect fetal gonadal androgen synthesis.

Amniotic Fluid↗
PubMed1980

[A measurement of immunoreactive prolactin in the decidual and villous tissues of early pregnancy, and a comparison with the prolactin in the amniotic fluid (author's transl)].

Several reports have revealed that human prolactin increases during pregnancy, not only in maternal and fetal serum but also in the amniotic fluid. The source and the role of prolactin in the amniotic fluid however, have not been clear up to now. In their incubation experiment, Riddick et al (29) proved that decidual tissue at term could secret immunoreactive prolactin (IR-PRL). In order to investigate the source of PRL in the amniotic fluid, we extracted IR-PRL from decidual or villous tissue in early normal pregnancies and measured it by a double antibody radioimmunoassay in this experiment. The results were the following: 1) We were able to measure IR-PRL from decidual or villous tissue in early pregnancy, the dilution curve of which paralleled pituitary standard prolactin. The cross reaction of a PRL standard preparation with HCG and HPL was not recognized within 10 micrograms/ml. 2) In human decidual tissue, the IR-PRL concentration began to increase at about the sixth week, arrived at the peak value, 81.06 +/- 2.13 ng/0.1 g dry weight (d.w.) in the eighth week, and did not change significantly after that. In human villous tissue, although the IR-PRL concentration was distinctly lower than it was in the decidual tissue, it increased gradually and reached the level of 37.44 +/- 7.16 ng/0.1g d.w. in the tenth week. 3) The extracted material (IR-PRL) from these two tissues in the 8th week, amniotic fluid at term, and pituitary standard PRL were passed through a Sephadex G-100 column (2 X 93 cm) with phosphate buffer and saline (0.01M, PH 7.4). In the chromatogram of these four test materials, one peak of IR-PRL was observed. The peak of IR-PRL of decidual and villous tissues and amniotic fluid revealed almost the same fraction number but elevated after the pituitary PRL preparation. 4) By gel filtration, the IR-PRL was able to be differentiated from HCG but not from HPL. The peak of HCG appeared earlier than the peak of IR-PRL and HPL. 5) The distribution of IR-PRL between human decidual and villous tissues was significantly different from that of HPL. IR-PRL concentration was higher in the decidual tissue than in the villous tissue, while HPL concentration was higher in the villous tissue than it was in the decidual tissue. From this observation, we could consider that the sources of these two hormones were different. The results of these experiments suggest that one of the sources of PRL in the amniotic fluid was the decidual tissue.

Amniotic Fluid↗
PubMed1986

Digoxin-like substance in amniotic fluid--fact or artifact?

A digoxin-like immunoreactive substance (DLIS) has been reported in the amniotic fluid. Since radioimmunoassay kits are standardized using serum-based standards, we hypothesized that measurement of DLIS may be an artifact related to the low protein content of amniotic fluid. We analyzed 12 amniotic fluid samples before and after supplementation with lyophilized human serum. The means +/- SDs for DLIS (nmol/l) at protein concentrations of 0, 32 and 63 g/l were 1.4 +/- 0.16, 0.6 +/- 0.09, and 0.4 +/- 0.09 nmol/l, respectively. We, therefore, hypothesize that DLIS in amniotic fluid may in part be explained by a technical artifact.

Amniotic Fluid↗
PubMed1990

[Levels of CA130 in maternal sera and amniotic fluid at various gestational ages].

We examined the CA130 concentration in the amniotic fluid, maternal sera, amnion, chorion, decidua and placenta. CA130 in the maternal sera showed an initial increase during early pregnancy, remained low from the 15th weeks of pregnancy until delivery, and then increased after term delivery (249u/ml, mean, n = 27) or mid-trimester abortions (844u/ml, n = 22). The CA130, concentration in the amniotic fluid was high in the mid-trimester and remarkably low at term. Among the tissues examined, amnion and decidua contained a relatively high concentration of CA130. Immunohistochemical examination also demonstrated abundant CA130 in the cytosol of amnion and decidua tissues. The pattern of changes in CA130 in amniotic fluid was similar to that in the amnion and decidua tissue. The results suggest that the amnion cells are the source of CA130 in the amniotic fluid and that the high concentration of CA130 in maternal serum after delivery originates in decidua tissue affected by the separation of the placenta.

Amnion↗
PubMedDate not supplied

[Appearance of inflammatory cytokines interleukin-1 beta and interleukin-6 in amniotic fluid during labor and in intrauterine pathogen colonization].

Subclinical intrauterine infections have been proposed to be one of the leading causes of preterm labor. The determination of inflammatory cytokines IL-1 beta and IL-6 in the amniotic fluid may be useful to identify women who have infection-associated preterm labor. Amniotic fluid was collected from 99 women during amniocentesis, during cesarean section or at the time of amniotomy using sterile technique. IL-1 beta and IL-6 were determined by a specific ELISA. Fluid of each sample was cultured for aerobic and anaerobic bacteria and for Mycoplasma hominis and Ureaplasma urealyticum. Different populations were identified according to the criteria "gestational age", "active labor", "positive amniotic fluid cultures". Interleukin-6 was detectable in all samples of amniotic fluid. The second-trimester (weeks 14-27) amniotic fluid concentration of IL-6 (18-2270 pg/ml) was higher than in the third trimester (weeks 28-42, 4-329 pg/ml). The difference was significant. Women in active labor had higher levels of IL-6 in their amniotic fluid than women not in labor (p < 0.01). There is no significant difference between women with preterm labor and delivery (weeks 28-37, 597-8670 pg/ml) and with term labor and delivery (weeks 38-42, 24-8300 pg/ml). Only culture negative samples were included in this population. Interleukin-1 beta was not detectable in the majority (90%) of these samples. 30% of the women in labor had positive amniotic fluid cultures. The IL-6 concentration of this population was not elevated in comparison to women in labor with negative cultures. Interleukin-1 beta was present in high concentrations (5-1100 pg/ml) in all fluid samples with detectable bacteria. Our data suggest that IL-1 beta may indicate subclinical uterine infection. IL-6 is elevated in all fluid samples of women in active labor.

Amniocentesis↗