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PubMed1990

Superiority of the four-quadrant sum over the single-deepest-pocket technique in ultrasonographic identification of abnormal amniotic fluid volumes.

Ultrasonographic estimation of amniotic fluid volume is an important adjunct to assessment of fetal well-being. However, no single method has emerged as most predictive. Many ultrasonographers use subjective or single-pocket guidelines in evaluation of amniotic fluid volume. We therefore assessed the ability of a maximum-vertical-pocket technique to identify patients with abnormal volumes of amniotic fluid. A total of 1168 patients was studied. Oligohydramnios (n = 76) was defined as an amniotic fluid index less than 5th percentile for gestational age (70 to 98 mm). Hydramnios (n = 51) was defined when the amniotic fluid index was greater than 95th percentile (185 to 249 mm). The ability of the maximum-vertical-pocket technique to identify cases with oligohydramnios by amniotic fluid index was poor: sensitivity was 42% and positive predictive value was 51%. Fifty-eight percent of cases with oligohydramnios by amniotic fluid index had "normal" values according to the single-pocket technique. The correlation coefficient between amniotic fluid index and maximum vertical pocket was 0.51, R2 = 24%. The correlation between the maximum vertical pocket and amniotic fluid index was somewhat better in cases of polyhydramnios (r = 0.79, R2 = 62%), but the sensitivity, positive predictive value, and false-negative rates were high as in oligohydramnios. These data suggest that the maximum-vertical-pocket technique has adequate specificity but is a poor screening tool. The results demonstrate that use of gestation-specific norms for the amniotic fluid index identifies abnormal amniotic fluid volumes more efficiently than the single-pocket technique.

Amniotic Fluid↗
PubMed1982

Aggregation of human platelets by amniotic fluid.

Twenty-four amniotic fluid samples were examined for their effects on human platelets. All samples caused irreversible platelet aggregation. The active material precipitated with high-speed ultracentrifugation and was completely inhibited by prior incubation with purified collagenase. The presence of free collagen in amniotic fluid was further confirmed by polyacrylamide-gel electrophoresis and hydroxyproline assays. Beside platelet-aggregating activity, amniotic fluid samples were also shown to significantly shorten the recalcification time of normal plasma. This procoagulant activity appears to be related to the presence of thromboplastin, collagen and other as yet unidentified procoagulant material in amniotic fluid. The presence of activators of platelets and clotting factors in amniotic fluid would account for the strong clot-promoting activity of this fluid. These studies suggest that the ideal management of the coagulopathy of pregnancy should include a combination of anticoagulant and antiplatelet drugs.

Amniotic Fluid↗
PubMed1998

Polymerase chain reaction in the detection of microbes in amniotic fluid.

Intra-amniotic infection during pregnancy can be caused by bacteria, viruses or protozoa, Toxoplasma gondii for example. Bacterial intrauterine infections are connected with premature birth, premature rupture of fetal membranes, and infective complications of both the mother and the newborn. Viral infections and Toxoplasma gondii can cause fetal malformations and illness with serious sequelae to the infant or fetal death in utero. Determining the causative agent is important and often greatly affects the prognosis of the newborn. Amniotic fluid is in most cases easily and safely obtainable during the second and third trimester and can be used in several microbiological assays. These include bacterial and viral cultures, Gram staining, quantitative assays for immunoglobulins or cytokines, and polymerase chain reaction (PCR) for detecting microbial DNA. This review concentrates on broad-spectrum or universal bacterial PCR for detection of bacterial DNA in amniotic fluid and on PCR assays for certain clinically important viruses and for Toxoplasma gondii.

Amniotic Fluid↗
PubMed1976

The effect of parturition on amniotic fluid lecithin concentration.

Amniotic fluid lecithin has been measured during the antenatal period and at comparable periods of gestation at the onset of spontaneous labour. Lecithin values were higher in labour, the difference being statistically significant in two of the three groups studied. Lecithin values were also measured serially during induced labour in 14 normal women at term. A significant fall was observed throughout labour. Creatinine levels were measured in the amniotic fluid in five of these patients and showed no significant change.

Amniocentesis↗
PubMed1979

The role of centrifugation in the measurement of surfactant in amniotic fluid.

Analysis of amniotic fluid fractions obtained by differential centrifugation has revealed the presence of intact globular-like structures of approximately 1 mu dimensions. These particles, which appear to be representative of fetal lung surfactant, begin precipitating at very low g forces and the extent of their removal by centrifugation was found to significantly alter L/S ratio measurements. This effect is particularly significant when moderate levels of these structures are present, which is usually between 34 and 37 weeks' gestation. False-negative L/S ratios could be attributed to this effect. Centrifugation can be employed to harvest these structures in reasonably pure form and measurement of their concentration, by phospholipid analysis, showed good correlation with fetal lung function in a trial study with 91 patients. These findings suggest that measurement of these surfactant particles harvested from amniotic fluid may provide a simple yet specific index of fetal pulmonary maturity.

Amniotic Fluid↗
PubMed1980

Neural origin of cells in amniotic fluid.

Cells from the amniotic fluid of fetuses with open neural tube defects (NTDs) have several abnormal characteristics of potential diagnostic value. The cell number in a unit volume of fluid is 10 to 100 times the normal range of cell count. The majority of cells adhere to tissue culture dishes within 24 hours of inoculation, instead of the 4 or 5 days required by normal amniotic fluid cells. The rapidly adhering cells morphologically resemble glial cells. Their Coulter volume is about twice the average seen in normal amniotic fluid--derived cells. This larger number of oversized, rapidly adhering cells is likely due to the continuous accumulation of neural cells in the amniotic fluid. We have detected the presence of the glial protein S-100 and the absence of the neuronal protein 14-3-2 by using a specific immunofluorescence assay. We conclude that fetuses with NTDs shed large numbers of glialike cells into the amniotic fluid where their detection may have diagnostic importance.

Amniotic Fluid↗
PubMed1986

Effect of acetone precipitation on the clinical prediction of respiratory distress syndrome when utilizing amniotic fluid lecithin/sphingomyelin ratios.

Amniotic fluid lecithin-to-sphingomyelin ratios are widely used to predict fetal lung maturity. The inclusion of acetone precipitation in the determination of the lecithin/sphingomyelin ratio has been widely accepted as a necessary step for enhancing predictivity. The lecithin/sphingomyelin ratio of 181 amniotic fluid samples was analyzed with and without acetone precipitation. Sensitivity, specificity, and predictive values were compared. Although there was a significant difference in the numeric value (p less than 0.001) between the two methods, the clinical prediction of the respiratory distress syndrome was not significantly enhanced by acetone precipitation. We conclude that acetone precipitation fails to improve the prediction of fetal lung maturity by lecithin/sphingomyelin ratio analysis.

Acetone↗
PubMed1979

[Prenatal sex determination by radioimmunoassay of testosterone with and without chromatography of the amniotic fluid (author's transl)].

Amniotic fluid testosterone measured by radioimmunoassay (RIA) without chromatography (immunoreactive testosterone) seems not to be a definitive test for prenatal sex determination in all cases. In this study testosterone (T) levels measured by RIA with chromatography of the amniotic fluid samples were compared with immunoreactive testosterone (iT) values, to determine the predictive accuracy of the two methods. In 111 amniotic fluid samples between 15 and 19 weeks of gestation iT and T were measured parallelly. There are significant differences between iT- and T-means of both sexes (p less than 0.001). 95%-condifence limits of iT-values of the male and female fetuses are largely overlapping. In contrast, the overlap of 95%-confidence limits of the T-values is only minor. The measurement of testosterone with chromatography of the amniotic fluid samples shows for prenatal sex determination in over 90% accuracy. This result is due to the elimination of sex-specific differences in crossreacting steroids within the amniotic fluid of both sexes.

Amniotic Fluid↗
PubMed1982

Radioimmunoassay of thyroxine and 3,3',5'-triiodothyronine (reverse T3) in human amniotic fluid.

Measurement of amniotic fluid iodothyronine concentrations may enable antenatal detection of fetal thyroid abnormalities; however, the delineation of normal ranges is complicated by methodological problems associated with strong and highly variable protein-binding, and specificity of antisera. Improved radioimmunoassays of thyroxine (T4) and 3,3',5-triiodothyronine (reverse T3, rT3) have been developed to overcome these problems. In normal pregnancy, mean rT3 concentrations at less than 17 weeks, 17-22 weeks and 35-42 weeks gestation were 3.6 nmol/l (n = 21), 6.1 nmol/1 (n = 14) and 0.66 nmol/1 (n = 39) respectively; corresponding mean T4 concentrations were 2.4 nmol/1, 6.5 nmol/1 and 3.6 nmol/1. rT3 concentrations showed a strong positive correlation with T4 concentration in each age range; however, the molar ratio of rT3:T4 decreased progressively with gestational age, from 1.69 at less than 17 weeks to 0.19 at 35-42 weeks. In both mid- and late gestation, rT3 and T4 concentrations were strongly correlated with total amniotic fluid protein concentrations.

Amniotic Fluid↗
PubMed2005

Interleukin-6 and interleukin-8 in cervical fluid in a population of Swedish women in preterm labor: relationship to microbial invasion of the amniotic fluid, intra-amniotic inflammation, and preterm delivery.

BACKGROUND: Intrauterine infection and inflammation in women with preterm labor are related to adverse perinatal outcome. Due to its subclinical nature, a correct diagnosis depends on retrieval of amniotic fluid. Amniocentesis is, however, not performed as a clinical routine because of its invasiveness. Hypothetically, cytokines in the cervical fluid may represent an alternative diagnostic approach. The aim was to examine cervical interleukin (IL)-6 and IL-8 in relation to microbial invasion of the amniotic fluid, intra-amniotic inflammation, and preterm birth in women in preterm labor. METHODS: Women with singleton pregnancies in preterm labor (<34 weeks of gestation) and intact membranes were included. Cervical (n = 91) and amniotic fluids (n = 56) were collected. Polymerase chain reaction for Ureaplasma urealyticum and Mycoplasma hominis and culture for aerobic and anaerobic bacteria were performed. IL-6 and IL-8 were analyzed with enzyme-linked immunosorbent assay. RESULTS: Non-lactobacillus-dominated biota was detected in cervical secretion in 25% (22/89) and the presence of micro-organisms in the amniotic fluid in 16% (9/56) of the patients. The presence of U. urealyticum in the cervical fluid (21/46) was associated with significantly higher levels of IL-6 in the secretion. IL-6 and IL-8 were significantly higher in cervical fluid of women with intra-amniotic infection and inflammation and in women who delivered < or =7 days and/or before 34 weeks of gestation. Cervical IL-6 > or = 1.7 ng/ml was related to intra-amniotic inflammation (relative risk: 2.67; range: 1.50-4.74) and had a sensitivity, specificity, positive predictive value, and negative predictive value of 58, 83, 75, and 69%, respectively, in the identification of intra-amniotic inflammation. Similar data were obtained for IL-8 > or = 6.7 ng/ml. CONCLUSIONS: High levels of cervical IL-6 and IL-8 are moderately predictive of intrauterine infection/inflammation and preterm delivery.

Adult↗
PubMed1984

Amniotic fluid analysis in prenatal diagnosis of neural tube defects: a comparison between six biochemical tests supplementary to the measurement of amniotic fluid alpha-fetoprotein.

Concanavalin A (con A) and lens culinaris agglutinin (LCA) microheterogeneity pattern of AFP (crossed affinity immunoelectrophoresis), alpha-2-macroglobulin and synaptic membrane protein D-2 (rocket immunoelectrophoresis) and qualitative (polyacrylamide gel electrophoresis) and quantitative (enzyme kinetic reaction rate) acetylcholinesterase were analysed in 87 consequtive samples from normal pregnancies and 37 abnormal samples (fetal neural tube defect or abdominal wall defect). Very few false positive results were obtained in normal pregnancies with any of the tests. In all cases of neural tube defects the correct result was obtained with qualitative acetylcholinesterase analysis, whereas only 2/3 of the abdominal wall defects were correctly predicted. Testing with con A or LCA was less optimal in neural tube defects, whereas all abdominal wall defects could be predicted correctly. Acetylcholinesterase in the quantitative test and protein D-2 did not decrease the rate of false results. Determination of the alpha-2-macroglobulin concentration performed well in the present study, but is not recommended because of the very high susceptibility to contamination of amniotic fluid with fetal or maternal blood.

Abdominal Muscles↗
PubMedDate not supplied

Elevated amniotic fluid nitric oxide metabolites and interleukin-6 in intra-amniotic infection.

OBJECTIVE: To compare amniotic fluid nitric oxide metabolites and interleukin-6 (IL-6) concentrations in patients with and without intra-amniotic infection. METHODS: Amniotic fluid nitric oxide metabolites, IL-6, Gram stains, glucose, leukocyte counts, leukocyte esterase activity, creatinine, pH, and specific gravity were determined in 14 patients with intra-amniotic infection and 26 patients without intra-amniotic infection. Intra-amniotic infection was defined as the presence of a positive amniotic fluid culture. The nitric oxide metabolites, nitrate and nitrite (NOx), were measured using Greiss reagent after reduction of nitrate to nitrite with aspergillus nitrate reductase. Interleukin-6 was measured by a two-site, enzyme-linked immunosorbent assay. Amniotic fluid nitric oxide metabolites and IL-6 concentrations were normalized by amniotic fluid creatinine levels. The Mann-Whitney U test, contingency table method, and Spearman's rank correlation test were used for statistical analyses. RESULTS: Amniotic fluid NOx and IL-6 levels were significantly higher in patients with intra-amniotic infection than in those without intra-amniotic infection (NOx: median = 2.06 mumol/mg creatinine, range = 0.74-6.81 versus 1.35 mumol/mg creatinine, range = 0.99-1.60, P = .01, IL-6: median = 2.00 micrograms/mg creatinine, range = 0.026-4.07 versus median = 0.04 micrograms/mg creatinine, range = 0.004-3.210, P = .0009, respectively). Patients with intra-amniotic infection had significantly elevated leukocyte counts, leukocyte esterase activity, Gram positive stains, and significantly lower amniotic fluid glucose levels compared with those without intra-amniotic infection. There were no differences in gestational age, maternal age, parity, race, pH, or specific gravity between the two groups. Amniotic fluid NOx was significantly correlated with IL-6 (r = .4, P = .02). Both amniotic fluid NOx and IL-6 were also positively correlated with amniotic fluid leukocyte counts, leukocyte esterase activity and Gram stains, and negatively correlated with glucose levels. CONCLUSIONS: Amniotic fluid NOx and IL-6 are significantly elevated and positively correlated during intra-amniotic infection. Both increased amniotic fluid IL-6 and nitric oxide may exert cytotoxic and cytostatic effects on the target cells. We suggest that measurements of amniotic fluid NOx and IL-6 may serve as useful clinical markers in patients with intra-amniotic infection.

Adolescent↗
PubMed1981

The synaptic membrane D2-protein in amniotic fluid from pregnancies with fetal neural tube defects.

The D2-protein is a neuronal membrane protein which has an immunochemically detectable soluble derivative in cerebrospinal fluid. We used rocket-on-line immunoelectrophoresis with an antiserum against rat synaptosomal membranes for demonstration of the human D2-protein in fetal cerebrospinal fluid and in amniotic fluids from pregnancies with fetal neural tube defects. D2 was neither found in normal amniotic fluids nor in cases of amniotic fluids from pregnancies with other malformations. Analysis of D2 in amniotic fluids may thus have a future role in the antenatal diagnosis of fetal neural tube defects.

Amniotic Fluid↗
PubMed1994

Investigation of the acid-base balance of coelomic and amniotic fluids in early human pregnancy.

OBJECTIVE: The aim of our study was to analyze and compare the acid-base status of coelomic and amniotic fluids in early human pregnancy. STUDY DESIGN: Coelomic fluid, amniotic fluid, and maternal serum were obtained from 55 normal pregnancies between 7 and 14 weeks of gestation and assayed for pH, PCO2, bicarbonate, chloride, phosphate, total protein, glucose, and lactate concentrations. RESULTS: The coelomic fluid had a significantly lower pH and base excess and contained significantly lower glucose, total protein, and bicarbonate concentrations and higher PCO2, lactate, and phosphate levels than did maternal serum. In the amniotic fluid significantly higher pH, base excess, and lactate and bicarbonate levels and lower concentrations of chloride and phosphate were found compared with the coelomic fluid. Little variation was observed in the coelomic and amniotic fluid composition before 11 weeks of gestation. A significant increase in PCO2, total protein, and chloride levels and a decrease in pH, base excess, and bicarbonate concentrations were observed in the amniotic fluid between 11 and 14 weeks compared with 7 to 10 weeks. CONCLUSIONS: The coelomic fluid composition was indicative of an anaerobic metabolic acidosis probably related to the accumulation of acid compounds from placental metabolism. During the same period of gestation the composition of the amniotic fluid demonstrated a metabolic alkalosis that probably arises from the accumulation of basic substances through the unkeratinized embryonic skin and from the metabolism of organic anions in the embryonic tissues. The changes in the amniotic composition and acid-base balance at the end of the first trimester may correspond to the switch from the mesonephros to the metanephros and result from the excretion in the amniotic fluid of acid metabolic fetal bioproducts through the maturing kidneys.

Acid-Base Equilibrium↗