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PubMed1990

Is amniotic fluid quantitation of value in the diagnosis and conservative management of prelabour membrane rupture at term?

This study examined the hypothesis that ultrasound quantitation of amniotic fluid depth is of value in the diagnosis and management of prelabour rupture of the membranes (PROM) at term. The deepest vertical pool was measured in 151 consecutive patients with a history of suspected PROM for at least 10 h before labour. In 100 patients the diagnosis of PROM was confirmed by the collection of amniotic fluid at the vulva. There was no difference in mean depth of amniotic fluid in 100 patients with confirmed PROM, compared with 51 in whom PROM was not confirmed (48.5 mm SD 16.4 vs. 60.1 mm SD 16.5); the frequency of oligohydramnios (fluid depth less than 30 mm) was 5% and 5.8% respectively. There was no relation between ultrasound amniotic fluid quantitation and the onset of labour, the duration of labour nor the frequency of oxytocin augmentation in labour. The results show that ultrasound quantitation of amniotic fluid is of no value in the diagnosis and conservative management of PROM at term.

Amniotic Fluid↗
PubMed1999

Amniotic fluid embolism and isolated disseminated intravascular coagulation.

PURPOSE: Disseminated intravascular coagulation (DIC) is a well-known complication of an amniotic fluid embolus. However, clinical experience has shown that, in some patients, clinical hemorrhage may be the initial presentation. Mortality in this subset of patients is high. This report describes a patient with a suspected amniotic fluid embolus who survived and in whom the initial presentation was post partum hemorrhage. CLINICAL FEATURES: During the post delivery repair of a fourth degree perineal tear a 29 yr old prima gravida was noted to have excessive vaginal bleeding despite a well contracted uterus. Laboratory investigations revealed a decrease in hemoglobin from 126 g x l(-1) to 86 g x l(-1) and a severe disseminated intravascular coagulopathy (PT 27.5 sec, APPT 149 sec, direct fibrinogen < 0.6 g x l(-1), FDP > 640 g x l(-1)). Treatment included massive blood component therapy and, eventually, total abdominal hysterectomy. The patient subsequently recovered without sequelae. In the absence of any other explanation, the coagulopathy was considered to be secondary to amniotic fluid embolus. CONCLUSION: Amniotic fluid embolus remains an important cause of maternal mortality. Clinical reports, reviews of the literature, and the development of the national registry have all contributed to our understanding of this syndrome. Contrary to earlier beliefs, not all patients present with sudden cardiorespiratory collapse. As the present case illustrates, a less common presentation is the development of an isolated DIC in the peripartum period without antecedent hemodynamic or respiratory instability. Therefore, anesthesiologists must maintain a high index of suspicion for the disorder in order to facilitate early recognition and treatment.

Adult↗
PubMed2006

Cardiopulmonary distress during obstetrical anaesthesia: attempts to diagnose amniotic fluid embolism in a case series of suspected allergic anaphylaxis.

BACKGROUND: Cardiopulmonary distress during obstetrical anaesthesia may result from a drug-induced allergic reaction, but, in the obstetrical setting, allergic anaphylaxis may be inseparable from amniotic fluid embolism in terms of the clinical presentation. Further investigations, using allergy tests and other laboratory analyses, are then needed to pursue a diagnostic clarification. METHODS: Twelve women suspected of having developed anaphylaxis during obstetrical anaesthesia underwent allergy follow-up investigations and further serological tests with the amniotic fluid embolism marker sialyl Tn and complement factors (C3 and C4) in an attempt to differentiate amniotic fluid embolism from drug-induced allergic anaphylaxis. RESULTS: The diagnostic programme revealed one case of probable amniotic fluid embolism and four cases of probable drug-induced allergic anaphylaxis. Of the remaining seven cases, there were two cases that, by diagnostic exclusion, could be classified as possible cases of amniotic fluid embolism. The cause of the reactions remained unresolved in five cases. CONCLUSIONS: It can be difficult to differentiate between anaphylaxis and amniotic fluid embolism, especially amongst survivors. Diagnostic markers that can be applied on peripheral blood samples are promising, but larger studies are needed to validate their use in the diagnosis of causes of cardiopulmonary distress during obstetrical anaesthesia.

Adult↗
PubMed1990

Detection of fetal blood contamination by amniotic fluid obtained during cordocentesis.

When a fetal blood sample is obtained by cordocentesis it is important to know whether the sample is diluted with amniotic fluid. This study was designed to assess whether contaminated fetal blood samples could be discriminated from noncontaminated ones by the ferning test, and if so what is the minimum dilution ratio of amniotic fluid/fetal blood that is detectable. Fetal blood samples were diluted with amniotic fluid and were tested for ferning under the microscope after the plasma was separated from the cells. At a dilution ratio of 0.2 ml of amniotic fluid to 1 ml of fetal blood, 30% of the samples tested positive for ferning. A rate of 100% detection of ferning was achieved at a dilution ratio of 0.6:1. In conclusion, screening fetal blood samples for ferning can detect amniotic fluid contamination. The sensitivity of the test for ferning depends on the dilution ratio. The test cannot assess how much amniotic fluid was added to the blood sample.

Amniotic Fluid↗
PubMed1984

Bacterial colonization of amniotic fluid in patients with intact membranes during labor.

Amniotic fluid from gravidas with intact membranes was obtained for bacteriologic culture at the time of cesarean section. The incidence of positive cultures from patients not in labor was 8%. When the length of labor was eight hours or less (mean 6.1 hours) and the membranes were intact, the incidence of positive cultures was 37%; in patients whose length of labor was 12 hours or less (mean 9.7 hours) with intact membranes, 55% of cultures were positive. The incidence of endomyometritis in patients with bacterial growth from the amniotic fluid cultures in each group was 33%, 33%, and 45%, respectively.

Amniotic Fluid↗
PubMed1975

Occurrence and properties of fetal intestinal glycosidases (disaccharidases) in human amniotic fluid.

alpha-Glucosidase, beta-glucosidase and beta-galactosidase were studied in cell-free amniotic fluid samples using corresponding 4-methylumbelliferyl-glycosides and a series of disaccharides (maltose, sucrose, trehalose, turanose, cellobiose, gentiobiose and lactose) as substrates. The glycosidases exhibited several properties of intestinal disaccharidases such as pH optimum between 5.2 and 6.4, more activity towards the disaccharides than the artificial substrates, tight association of the activities with sedimentable complexes and beta-glucosidase and beta-galactosidase activities exerted by a single catalytic site. With the disaccharides as substrates, the amniotic fluid glycosidase activities were well correlated to those reported in the literature for fetal intestine of corresponding gestational ages. The presence of intestinal disaccharidases in amniotic fluid indicates that the fetal intestine contributes to the protein and enzymes of amniotic fluid.

Amniotic Fluid↗
PubMed2004

Amniotic fluid has higher relative levels of lentivirus-specific antibodies than plasma and can contain neutralizing antibodies.

BACKGROUND: The in utero transmission rate of HIV-1 is estimated to be 10-15% in the absence of interventions and breastfeeding. Natural protective mechanisms involving lentivirus-specific antibodies may therefore exist to limit in utero transmission of lentiviruses. OBJECTIVES: HIV-1- and SIV-specific immunoglobulin G (IgG) levels in amniotic fluid samples from humans and rhesus macaques were assessed. STUDY DESIGN: HIV-1- and SIV-specific immunoglobulin G levels, relative to total IgG concentrations in amniotic fluid samples from humans and rhesus macaques, were determined using a quantitative Western blotting procedure. Amniotic fluid from rhesus macaques was tested for the ability to neutralize SIV infection of CEMX174 cells. RESULTS: The levels of HIV-1- and SIV-specific immunoglobulin G, relative to total IgG concentrations in amniotic fluid samples from humans and rhesus macaques, were approximately 3-10-fold higher than in plasma. The ability of antibodies in human amniotic fluid samples to neutralize viral infectivity could not be assessed, because zidovidine was present in the samples. Most amniotic fluid samples from rhesus macques not treated with antiretrovirals were able to neutralize SIV infectivity, except for a sample from a SIV positive rhesus whose infant was infected in utero. CONCLUSIONS: Active immunity to HIV-1 resulting in virus-specific antibodies in amniotic fluid exists, and may be a natural barrier to in utero infection. This may provide hope for stimulating neutralizing antibody via vaccine design.

Amniotic Fluid↗
PubMed1990

Detection of platelet-activating factor in amniotic fluid of complicated pregnancies.

The ether phospholipid PAF (1-alkyl-2-acetyl-sn-glycero-3-phosphocholine) was originally described as a potent bioactive lipid associated with inflammatory responses. More recently, we have suggested a functional role for PAF in fetal lung maturation and the initiation of parturition. Previously, PAF was detected in the amniotic fluid of women at term during labor. A significant proportion of this PAF was associated with a lamellar body-enriched fraction. In addition, the PAF concentration was elevated in fetal rabbit lung during the latter stages of gestation and in human fetal lung in organ culture. It was therefore concluded that the PAF present in amniotic fluid during labor was, in part, of fetal lung origin. In the reported study, amniotic fluid samples were obtained from a group of patients with uncomplicated pregnancies at term "not in labor" and "in labor" and a group with complicated pregnancies. We found an eightfold greater concentration of PAF in amniotic fluid obtained from the "term, in labor" samples compared with that of the "term, not in labor" samples (40 vs. 312 fmol/ml). A twentyfold elevation in PAF (838 fmol/ml) was evident in the amniotic fluid of patients incurring "preterm labor" with an average gestational age of 32 weeks compared with the "term, not in labor" group. PAF concentrations also were elevated to 756 fmol/ml amniotic fluid in a group of patients with an average gestational age of 31.5 weeks who had premature rupture of membranes. We have previously suggested that a second autacoid, PAF, in addition to eicosanoids, may function in the initiation of parturition at term in uncomplicated pregnancies. On the basis of our findings of a severalfold increase in the PAF concentration in amniotic fluid from complicated pregnancies, it is suggested that this potent activator of myometrial contraction, together with the eicosanoids, may be a contributing factor associated with premature labor.

Amniotic Fluid↗
PubMed1994

Amniotic fluid embolism as a cause of sudden maternal death.

The aetiology of amniotic fluid embolism has remained very much an enigma, although recent evidence points towards a combination of a severe haemodynamic disturbance, consisting of transient pulmonary hypertension, profound hypoxia and left ventricular failure, followed by secondary coagulopathy in about 40 per cent of patients who survive the initial event. Leucotrienes, prostaglandins and other vasoactive substances contained in amniotic fluid are postulated to play a fundamental role in its pathogenesis. In addition, amniotic fluid is also thought to possess thromboplastin-like properties. In common with all other causes of maternal death, it warrants a thorough and careful medico-legal investigation.

Adult↗
PubMed1977

Amniotic fluid lecithin/sphingomyelin ratio changes related to centrifugal force.

Lecithin/sphingomyelin ratio (L/S ratio) in amniotic fluid has gained wide clinical acceptance as an index of fetal lung maturity. We determined L/S ratios of amniotic fluids centrifuged at various "g-forces." Our studies demonstrate that the L/S ratio value is highly dependent on the g-force used to prepare the fluid. We recommend standardization of the g-force, time, and temperature used in preparation of the amniotic fluid for L/S ratio determination.

Amniotic Fluid↗
PubMed1984

The natural history of prenatal hydronephrosis with normal amounts of amniotic fluid.

Thirteen cases of fetal hydronephrosis associated initially with normal volumes of amniotic fluid were diagnosed by maternal sonography. No invasive procedures were done in utero. Postnatal evaluation demonstrated 8 neonates with urinary tract obstruction and 5 normal neonates. Long-term followup of these 13 patients revealed that 12 are healthy and have normal renal function. The exception is a child whose amniotic fluid decreased during pregnancy. Our data suggest that fetuses with normal volumes of amniotic fluid do well. Treatment should be limited to frequent prenatal sonography and subsequent early postnatal evaluation. Caution should be exercised with the diagnosis of hydronephrosis, since 5 of our patients had false positive findings. In the rare instances when oligohydramnios develops during pregnancy fetal intervention may be warranted.

Amniotic Fluid↗
PubMed2005

Broadband measurements of the frequency dependence of attenuation coefficient and velocity in amniotic fluid, urine and human serum albumin solutions.

The frequency dependence of attenuation coefficient in amniotic fluid, urine and 4.5% and 20% human serum albumin solutions over the frequency range 5 MHz to 25 MHz was measured at both room temperature and physiological temperature using a variable path length technique. A 15 MHz (13 mm diameter) transducer was used to produce a broadband single-cycle pulse and a 4 mm diameter bilaminar polyvinylidene difluoride membrane hydrophone was used to detect the attenuated pulse. Standard time-of-flight measurement techniques were used to measure the acoustic velocity in the same fluid samples. At physiological temperature, the attenuation coefficients in amniotic fluid, urine and 4.5% and 20% human albumin solution were found to be 0.0053 f(1.65), 0.0047 f(1.67), 0.019 f(1.57) and 0.167 f(1.27) dB cm(-1), respectively, where f is in MHz. The velocities in amniotic fluid, urine and 4.5% human albumin solution at physiological temperature were found to be 1541.1 m s(-1) +/- 1.3 m s(-1), 1551.3 m s(-1) +/- 1.3 ms(-1) and 1547.3 m s(-1) +/- 1.0 m s(-1), respectively. The results provide unique data over the diagnostic and therapeutic ultrasonic frequency range that can be used as input data for theoretical models that attempt to simulate nonlinear pressure fields and temperature rises from medical ultrasonic transducers.

Amniotic Fluid↗
PubMed1979

Significance of amniotic fluid glucose in late pregnancy.

Glucose levels were estimated in over 150 amniotic fluid samples and were found to fall with advancing gestational age. Significantly lower levels were found in post-term pregnancies and in association with fetal growth retardation. Amniotic fluid glucose estimation was found to be superior to human placental lactogen in distinguishing between normal pregnancies and those complicated by fetal growth retardation. The role of the membranes in influencing the level of amniotic fluid glucose was investigated using in vitro perfusion experiments. The permeability of the membranes to glucose decreased with advancing gestational age.

Amniotic Fluid↗
PubMed1996

Sensitive method for the determination of pulmonary surfactant phospholipid/sphingomyelin ratio in human amniotic fluids for the diagnosis of respiratory distress syndrome by thin-layer chromatography-immunostaining.

By TLC-immunostaining with the monoclonal antibody VJ-41, which preferentially reacted with sphingomyelin (Sm) and disaturated fatty acid-containing phosphatidyl choline (DSPC), Sm and surfactant phospholipid dipalmitoyl PC were only detected in the lipid extracts from human amniotic fluid. The method was useful in the selective and simultaneous determination of surfactant phospholipid and Sm concentrations in the amniotic fluids to determine the level of maturity of the lungs of the fetus. By measuring the density of spots visualized by TLC-immunostaining, we detected Sm at a sensitivity two times higher than that for dipalmitoyl PC using the antibody. More than 50 ng of dipalmitoyl PC and Sm was detected on the same TLC plate and the standard curves were linear up to 1 microgram of phospholipids. The method was applied to determine the surfactant phospholipid/Sm ratio in 20 microliter of the amniotic fluids obtained at delivery, and the amniotic fluids from the women who delivered a baby suffering from respiratory distress syndrome (RDS) were easily discriminated from the normal amniotic fluids. In an analysis of 200 microliter of amniotic fluids from 4 RDS cases and 16 normal baby cases, the mean DSPC/Sm ratios were 0.97 +/- 0.53 and 5.75 +/- 1.29, respectively.

Amniocentesis↗
PubMed1976

Fetal lung maturation IV: the release of phosphatidic acid phosphohydrolase and phospholipids into the human amniotic fluid.

The relationship between surface active material and phosphatidic acid phosphohydrolase (PAPase) activity was examined in human amniotic fluid after centrifugation at 105,000 X g for one hour. The distribution of PAPase activity between the pellet and supernatant fractions was similar to that of phospholipids in the amniotic fluid. The majority of the PAPase activity was found to be associated with the pellet fraction. Similarly, 82% of the phospholipid was also present in this fraction. Of the total palmitate present in the original sample, approximately 90% was found in the pellet after centrifugation. Palmitic acid constituted 75% of all fatty acids present in the phosphatidylcholine identified in the pellet. By sharp contrast only 4% of the total protein was pelletized by centrifugation. The pelletized fraction isolated from amniotic fluid after 105,000 X g centrifugation closely resembles the lamellar bodies in: (1) its phospholipid pattern; (2) palmitate concentration in phosphatidylcholine; and, (3) the presence of PAPase activity with a high specific activity. Collectively, these findings lend strong support to the concept that a lamellar-like body is released from fetal lung into the amniotic fluid.

Amniotic Fluid↗
PubMed2004

The effect of common clinical contaminants on amniotic fluid fluorescence polarization results.

OBJECTIVE: To determine the effect of blood, meconium, and vaginal secretions on amniotic fluid (AF) fluorescence polarization results. METHODS: Amniotic fluid was collected by transabdominal amniocentesis from women at 20-41 weeks of gestation and contaminated with blood, meconium, and vaginal secretions to concentrations of 0.5, 1, 2, 5, and 10%. An additional 20% concentration was performed with meconium and vaginal secretions. Fluorescence polarization was determined by a TDx Analyzer with the NBD-PC fluorescent probe. Results were compared for each contaminant by concentration level using repeated-measures analysis of variance. RESULTS: Forty-eight samples from women at a mean gestational age of 35 weeks (range 20-41.5 weeks) were evaluated. Before contamination, 16 (33%) samples had fluorescence polarization values greater than 290 mPol (immature), 10 (21%) were 260- 289 mPol (transitional), and 22 (46%) were less than 260 mPol (mature). Contamination with blood significantly altered fluorescence polarization values in AF samples with baseline values in the immature and mature categories such that values trended toward the transitional range. Contamination of baseline immature samples with vaginal secretions at 20% contamination level resulted in more mature fluorescence polarization values. Contamination with meconium more than 2% in the baseline immature category or more than 20% in the baseline transitional category also resulted in significantly more mature fluorescence polarization values. CONCLUSION: Amniotic fluid contamination with blood can result in more transitional range fluorescence polarization values, whereas contamination with meconium and vaginal secretions can result in more mature fluorescence polarization values.

Amniocentesis↗
PubMed2004

High-resolution 1H NMR spectroscopy of amniotic fluids from spina bifida fetuses and controls.

OBJECTIVE: To quantify proton containing metabolites by in vitro 1H NMR spectroscopy of amniotic fluids from fetuses with spina bifida and controls. STUDY DESIGN: Fourteen amniotic fluids from spina bifida fetuses and 18 controls were obtained. Concentrations of carbohydrates, organic acids and amino acids were determined. Multiple linear regression analysis was used to evaluate the data. RESULTS: At 15 and 39 weeks amenorrhea, the estimated median amniotic fluid concentrations of succinic acid and glutamine were significantly higher in the spina bifida group compared to controls, 37 and 64%, respectively. Whereas creatine and creatinine were significantly lower, 27 and 36%, respectively. Amenorrhea influenced the concentrations of most compounds with the exception of lactic acid. CONCLUSION: 1H NMR spectroscopy shows significantly higher succinic acid and glutamine concentrations in amniotic fluids derived from spina bifida fetuses compared with controls. A derangement in amino acid metabolism is suggested.

Adult↗
PubMedDate not supplied

Increased amniotic fluid alpha-fetoprotein in patients with fetal nuchal edema.

The alpha-fetoprotein concentration in the amniotic fluid of 51 fetuses with isolated nuchal edema and normal karyotypes was compared to that of the next 51 patients of comparable gestational age with normal ultrasounds and karyotypes. The mean alpha-fetoprotein in amniotic fluid was 1.26 +/- 0.45 in the nuchal edema group and 1.01 +/- 0.3 in controls (t = 3.287, p = 0.002). Acetylcholinesterase evaluation was indicated by abnormally elevated alpha-fetoprotein in 4% of amniotic fluid samples from the study group and none of the controls. We concluded that alpha-fetoprotein is higher in amniotic fluid from pregnancies with isolated fetal nuchal edema and normal karyotype. Possible leakage of protein from enlarged cervical lymphatics associated with fetal nuchal edema may explain these findings.

Amniocentesis↗