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PubMed1999

[Study and application on the device of the drop volume of amniotic fluid in estimating fetal lung maturity].

A novel device of drop volume of amniotic fluid has been made to estimate fetal lung maturity. The design of the device is based on the principle that the surface tension of amniotic fluid is inversely proportional to the quantity of surfactant in the solution. The device measures the falling time of fluid drops from drop-tube and estimates the fetal lung maturity by using the method of comparison and electric-optic timing-counting. 148 samples of amniotic fluid were measured by the device and the data were compared with those obtained by biochemical method. The results demonstrate that this device has high stability and accuracy, and the rate of agreement between the two methods is as high as 93%.

Amniotic Fluid↗
PubMed1995

Amniotic fluid composition and fetal and placental growth rates in genetically hypertensive and normotensive rats.

Reduced birth weight has been observed in offspring of the spontaneously hypertensive rat (SHR) and in human hypertension. To determine which uterine factors might contribute to this fetal underdevelopment, fetal and placental growth rates and the volume and composition of amniotic fluid were measured in SHR and normotensive control Wistar Kyoto (WKY) rats during the final trimester of intra-uterine development. SHR and WKY fetuses were collected on Days 15-22 of pregnancy, and fetal and placental weight and amniotic fluid volume were recorded. The sodium and potassium concentrations of amniotic fluid were also measured. Placental weight was significantly lower in SHR than in WKY between Days 15 and 20 of gestation, but significantly higher on Days 21 and 22. Fetal weight was significantly lower in SHR between Days 17 and 22. These differences were reduced or abolished when fetal and placental weights were corrected for differences in maternal weight between strains. Amniotic fluid volume was significantly lower in SHR between Days 15 and 18, but significantly higher at Days 20, 21 and 22. Amniotic fluid sodium concentration was relatively constant over the period of observation and not different between strains. SHR amniotic fluid potassium concentration was significantly lower than that of WKY near term. Thus, the altered fetal and placental weight of SHR may be due to the overall reduced growth rate of this strain. However, the rate of fluid and electrolyte resorption close to term is markedly different between strains. The mechanism for this altered fluid and electrolyte handling by the SHR feto-placental unit remains to be determined.

Amniotic Fluid↗
PubMed1987

Proliferation of group B streptococci in human amniotic fluid in vitro.

The group B Streptococcus is one of the most virulent organisms causing perinatal infection. Human amniotic fluid from the second and third trimesters was pooled and analyzed for electrolytes, protein, albumin, zinc, inorganic phosphorus, ferritin, lysozyme, and immunoglobulins. We inoculated replicates of specimens with known virulent strains of group B streptococci (893, 891, and 878) and Escherichia coli (C5) with Todd-Hewitt broth and normal saline solution used as controls. Group B streptococci strains 893 and 891 proliferated rapidly at rates similar to their rates in Todd-Hewitt Broth. Strain 878 grew at a rate slower than that of strains 893 and 891. The amniotic fluid specimens were similar with respect to factors reported as inhibitory to bacterial proliferation. Second- and third-trimester amniotic fluid supports the growth of group B streptococci as well as a culture medium optimized for bacterial growth. Strain-specific variance in group B streptococci growth rates in amniotic fluid may have clinical significance for those at risk for group B streptococci infection.

Amniotic Fluid↗
PubMed1978

The significance of a low amniotic fluid creatinine and a mature lecithin/sphingomyelin ratio.

Creatinine levels were measured in 546 specimens of amniotic fluid with a lecithin/sphingomyelin ratio of 2.5 or more. With amniotic fluid creatinine levels below the normal range, 3 of 6 infants had major congenital abnormalities and two had severe rhesus isoimmunization; 3 of the infants died. Of 514 cases with amniotic fluid creatinine levels within the normal range (mean +/- 2 SD), 13 babies (2.5%) had major congenital abnormalities but only one of the babies died, giving a perinatal mortality rate of 0.2%. The significance of these findings is discussed.

Amniotic Fluid↗
PubMed1978

Maternal and amniotic fluid 17 alpha-hydroxyprogesterone levels during pregnancy: diagnosis of congenital adrenal hyperplasia in utero.

17 alpha-Hdroxyprogesterone levels (17 alpha-OHP) were measured in 70 samples of amniotic fluid and 30 samples of maternal serum obtained at different stages of normal pregnancy and in samples of maternal serum and amniotic fluid from a pregnancy with the fetus affected with congenital adrenal hyperplasia. The mean level of 17 alpha-hydroxyprogesterone in the amniotic fluid from control pregnancies was 133.9 +/- 7.6 ng. per 100 ml. (range, 25.1 to 266.6 ng. per 100 ml). The levels were significantly higher in midpregnancy (157.4 +/- 8.4 ng. per 100 ml.) than in late pregnancy (79.2 +/- 6.8 ng. per 100 ml.) (p less than 0.01). Amniotic fluid 17 alpha-OHP levels in the affected pregnancy were significantly higher than the control levels. Mean maternal 17 alpha-OHP level during early pregnancy and midpregnancy was 259.5 +/- 22 ng. per 100 ml. and there was a two-to three-fold increase after 37 weeks (672.2 +/- 61 ng. per 100 ml.) The maternal 17 alpha-OHP levels in the affected pregnancy were significantly higher than the control levels after 34 weeks, but before 34 weeks, the level was within the range seen in control pregnancies. Measurement of 17 alpha-OHP levels in the amniotic fluid before 24 weeks and maternal serum after 34 weeks can be utilized for the prenatal diagnosis of congenital adrenal hyperplasia.

Adrenal Hyperplasia, Congenital↗
PubMed1976

Accurate amniotic fluid bilirubin analysis from the "bloody tap". A preliminary report.

The quantitation of bilirubin in amniotic fluid is of paramount importance in prognosticating the severity of Rh isoimmunization. Amniotic fluid contaminated by maternal blood can result in erroneous results when direct spectrophotemetric analysis is performed on such fluid. The technique and results of a one-step chloroform extraction performed on "bloody" amniotic fluid is presented. Results confirm that chloroform extraction yields more accurate clinical information in regard to Rh isoimmunized patients in whom a "bloody tap" is obtained.

Amniocentesis↗
PubMed2003

Mechanisms responsible for postnatal middle ear amniotic fluid clearance.

Neonatal guinea pigs show signs of a temporary conductive hearing loss during the first few days after birth. It has been suggested that this is due mainly to the presence of amniotic fluid in the middle ear (ME) cavity at birth and its subsequent clearance. This study was designed to try to identify the mechanisms responsible for the amniotic fluid clearance from the ME after birth by means of several experiments in guinea pigs. The osmolarity of the blood, amniotic fluid and the fluid in the ME cavity of guinea pig fetuses was measured. Serum and normal saline were introduced into the ME of older animals and fluid clearance was monitored short- and long-term by microscopic observation, tympanometry and estimation of residual fluid. Following instillation of 1/5 normal saline and normal saline into the ME cavity, the osmolarity of the remaining fluid was determined, short- and long-term. Clear osmotic pressure gradients were found between amniotic fluid (low pressure), fetal blood (higher pressure) and the fluid in the fetal ME (intermediate between them). The MEs into which normal saline had been introduced developed negative pressure and, over several days, were cleared of fluid. When serum was applied, ME pressure remained close to atmospheric and the fluid was not cleared. Hypotonic saline application led to an increase in the osmotic pressure in the fluid remaining in the ME. It is concluded that most of the amniotic fluid is cleared from the neonatal ME cavity by water outflow into the blood due to osmotic pressure gradients.

Acoustic Impedance Tests↗
PubMed1982

The relationship of amniotic fluid phosphate-to-zinc ratios to post-cesarean section infection.

Although many reports concerning risk factors for post-cesarean section febrile morbidity have been published, few have considered the antibacterial activity of amniotic fluid. This study, in which the amniotic fluid phosphate-to-zinc ratios were used as a reflection of antibacterial activity, demonstrates that, among 85 patients who underwent elective repeat cesarean sections, less febrile morbidity was present when the patient's amniotic fluid had greater antibacterial activity. There was less standard fever, use of antibiotics, and endometritis among patients whose amniotic fluid had lower phosphate-to-zinc ratios.

Amniotic Fluid↗
PubMedDate not supplied

Rapid detection of group B streptococcus and Escherichia coli in amniotic fluid using real-time fluorescent PCR.

OBJECTIVE: To establish reliability and validity of real-time fluorescent PCR for early detection of bacterial invasion of the amniotic cavity. METHODS: Amniotic fluid samples from 40 patients undergoing mid-trimester genetic amniocentesis were incubated for 6 h at 37 degrees C and were cultured on media specific for group B streptococcus (GBS) and E. coli. Concurrently, samples were analyzed with real-time fluorescent PCR (Roche LightCycler) using DNA primers and probes designed to detect the CAMP factor encoding cfb gene and uidA gene of GBS and E. coli, respectively. For positive control and to simulate amniotic fluid colonization, 104 cfu/ml of GBS and E. coli were inoculated on sterile amniotic fluid and incubated for 6 h. Bacterial genomic DNA for the two organisms was extracted and purified via the two-step precipitation method using a commercial kit. The real-time PCR assays were also tested against 25 non-GBS and non-E. coli bacterial species. The lower limit of detection for each pathogen was established using serial dilution of bacterial genomic DNA. RESULTS: All patient samples were negative for evidence of GBS and E. coli with both culture and real-time PCR methods. Amniotic fluid samples inoculated with GBS and E. coli were positive with real-time PCR whereas the 25 bacterial species other than GBS or E. coli tested negative with the assay. Average total sample processing time including the pre-enrichment step was 7 h 40 min. The average cost for DNA extraction and PCR testing was 8.50 dollars per test. CONCLUSION: Real-time fluorescent PCR is a valid and reliable method for detection of specific pathogens in amniotic fluid. This technique is sensitive for low inoculation levels. Real-time fluorescent PCR has potential to impact clinical management as a rapid, reliable detection method for GBS and E. coli in chorioamnionitis.

Amniotic Fluid↗
PubMed1996

Pregnancy outcome after early amniotic fluid leakage after transabdominal multifetal reduction.

OBJECTIVE: To assess the importance of amniotic fluid leakage in the early period ( < 14 days) after the fetal reduction procedure. DESIGN: Prospective clinical study. SETTING: Pregnant women who underwent fetal reduction to twins in an academic, tertiary perinatal department. PATIENTS: Sixty triplet and 31 quadruplet pregnancies were identified before the ninth postmenstrual week of gestation. All patients underwent transabdominal multifetal pregnancy reduction was performed within 14 days of the procedure. INTERVENTIONS: Transabdominal multifetal pregnancy reduction from triplets and quadruplets to twins. MAIN OUTCOME MEASURE: Amniotic fluid leakage in the early period after fetal reduction. RESULTS: Early PROM occurred in eight (13.3%) patients from the triplets group and in six (19.3%) patients in the quadruplet group. Three of 60 (5.0%) patients from the triplet group and 1 of 31 (3.2%) patients from the quadruplet group miscarried before 24 weeks gestation. However, none of these patients had had PROM during the early period after the procedure. Early PROM did not influence the incidence of premature contractions of delivery and the reduction procedure, and 59% (99/169) of those who completed 24 gestational weeks delivered between 25 and 37 weeks. CONCLUSION: The presence of amniotic fluid leakage in the period close to the multifetal reduction procedure, although alarming, is not ominous for the remaining fetuses. We see no reason for any intervention in these patients.

Abortion, Spontaneous↗
PubMed1985

The assessment of fetal pulmonary maturity by fluorescence polarization (FP-value) of pooled vaginal amniotic fluid associated with ruptured membranes.

This prospective study was undertaken to examine the reliability of fluorescence polarization (FP) readings on amniotic fluid collected from the posterior fornix of the vagina after membranes have ruptured. This method was chosen because it is as accurate as the L/S ratio, but it is simpler, faster and requires only 0.5 ml of sample. Forty-seven out of 55 patients were eligible for the study, for a success rate of 85%. Respiratory distress syndrome (RDS) occurred in one out of 29 neonates with FP in the mature or low risk group. In the high risk group for RDS, 7 out of 12 developed the syndrome. In 11 patients, FP-values obtained from transabdominal amniocentesis were not significantly different from those obtained from pooled vagina amniotic fluid once membranes were ruptured. Analysis of pooled vaginal amniotic fluid is simple, non-invasive and capable of being performed with a high rate of success. FP-values from properly collected pooled vaginal amniotic fluid can be used in the assessment of functional fetal lung maturity.

Amniocentesis↗
PubMed1977

[The determination of surface tension in amniotic fluid as a simple method for the diagnosis of fetal lung maturity (author's transl)].

For the past several years it is possible to determine the maturity of the fetal lung from the amniotic fluid. Towards the end of the pregnancy the content of surface active substances for instance Lecithine, increases in the amniotic fluid. It is therefore possible to determine the maturity of the fetal lung directly by measurements of the surface tension in the amniotic fluid. In 265 patients from 17 to 42 weeks gestation a total of 340 determinations of the surface tension in the amniotic fluid were carried out. A simple commercial interfacial tensiometer was used. The clinical value of the measurements was determined by the occurrance of a respiratory distress syndrome which was objectively evaluated by the so called Hobel Score. The determination of the surface tension for the amniotic fluid is valuable as a screening test prior to the determination of the relatively expensive L/S ration. The test was compared with the Clements Test which is also a screening procedure.

Amniotic Fluid↗
PubMed1979

[Standardization criteria for the study of fetal lung maturity by means of gas-liquid chromatography of the fatty acid content of the amniotic fluid].

Gas-chromatographic analysis of the fatty acids (P/S ratio) in 10 samples of amniotic fluid and 10 samples of the pellets obtained after centrifugation of amniotic fluid at 3500 X g for 60 minutes were carried out to evaluate the effects of contaminants that might be present in amniotic fluid. The P/S ratio is used as an index of the degree of maturity of the fetal or neonatal lung. We propose a standard procedure of centrifugation for 60 minutes at 3500 X g followed by extraction and gas-chromatography as a rapid, valid way to measure the P/S ratio.

Amniotic Fluid↗
PubMed1999

In vitro survival of Listeria monocytogenes in human amniotic fluid.

A Listeria monocytogenes strain (CA01/93), haemolytic and virulent in mice, was inoculated in 16 samples of sterile human amniotic fluid to study the growth curves and to provide more information about the pathophysiology of the microorganism in pregnancy. A control test for every analysis was performed with an Escherichia coli strain (CN 02/95). Regardless of the amniotic fluid samples were taken at 34th-39th week of gestation, when it expresses maximum ability to inhibit growth of E. coli, the growth curves of L. monocytogenes do not show any bactericidal (only bacteriostatic) activity of the amniotic fluids against the tested strain. This gives an interesting result about the pathogenesis of the infection in pregnancy and about the potential environmental contamination due to long surviving times of the microorganism in-amniotic fluid.

Amniotic Fluid↗
PubMed2001

The relationship between amniotic fluid matrix metalloproteinase-8 and funisitis.

OBJECTIVE: The fetal inflammatory response syndrome is a multisystem disorder associated with impending preterm delivery and adverse neonatal outcome. Inflammation of the umbilical cord--funisitis--is the histologic counterpart of fetal inflammatory response syndrome and has been associated with an increased risk for the development of cerebral palsy. Neutrophils found in the amniotic cavity are of fetal origin. Therefore, neutrophil secretory products may be an index of the fetal inflammatory response syndrome. To test this hypothesis, we examined the relationship between levels of amniotic fluid matrix metalloproteinase-8 and funisitis. STUDY DESIGN: The relationship between the presence of funisitis and concentrations of amniotic fluid matrix metalloproteinase-8 was examined in 255 consecutive patients who delivered preterm singleton neonates (gestational age, <36 weeks) within 72 hours of amniocentesis. Amniotic fluid was cultured for aerobic and anaerobic bacteria and for mycoplasmas. Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton jelly. Matrix metalloproteinase-8 was measured by use of a specific immunoassay. Nonparametric statistics were used for analysis. RESULTS: Funisitis was present in 23% (59/255) of cases. Patients with funisitis had a significantly higher median concentration of amniotic fluid matrix metalloproteinase-8 than those without funisitis (median, 433.7 ng/mL [range, 1.5-3836.8 ng/mL] vs median, 1.9 ng/mL [range, <0.3-4202.7 ng/mL]; P <.001). The diagnostic indices of matrix metalloproteinase-8 (cutoff, 23 ng/mL) in the identification of funisitis were: sensitivity of 90% (53/59), specificity of 78% (153/196), positive predictive value of 55% (53/96), and negative predictive value of 96% (153/159). CONCLUSIONS: There is a strong association between increased levels of amniotic fluid matrix metalloproteinase-8 and funisitis. We propose that determination of amniotic fluid matrix metalloproteinase-8 concentrations may assist the assessment of the fetal inflammatory status, thereby eliminating the need for fetal blood sampling.

Adult↗
PubMed1995

Respiration of amniotic fluid in near-term foetal rabbit.

OBJECTIVE: To examine the existence of amniotic fluid inhalation in foetal rabbit near term. STUDY DESIGN: Rabbit red cells labelled with 51 radio-chromium (Cr51-S1: Injectable solution sodium chromate, volumic activity: 74 MBq/ml; Cis-BioInternational, France) were injected into the amniotic sac of 24 New Zealand White foetal rabbits (mean gestation: 31 days) at day 25 per-laparotomy. At day 26, just prior to caesarean section, human serum albumin labelled with 125 radio-active iode (125I-HSA) (SERALB-125: human serum albumin labelled with radioactive Iode 125, volumic activity: 185 kBq/ml, Cis-BioInternational, France) was injected into each amniotic sac. The lungs, digestive tracts, kidneys and liver were excised separately and radioactivity counted in each organ. RESULTS: On day 26 of gestation, the 51Cr-RC radioactivity rate per gram of tissue in lungs, digestive tract amniotic fluid, liver and kidneys were respectively 1.66 +/- 2.8%, 1.15 +/- 1.6%, 0.015 +/- 0.02% and 0.04 +/- 0.07% of the total amount of radioactivity injected into the amniotic sac at day 25. The lungs' radioactivity was significantly higher than liver (t = 2.94, P < 0.01) or kidneys radioactivity (t = 2.38, P < 0.05). The 125I-HSA injected just prior to caesarean section at day 26 was not found in any foetal organ. CONCLUSIONS: Lung radioactivity is not related to gasps induced by caesarean section, or to a vascular diffusion since lung radioactivity was significantly higher than liver or kidneys' radioactivity. The results of these series of experiments demonstrate that amniotic fluid inhalation does exist in foetal rabbit near term.

Amniotic Fluid↗
PubMed2002

A review of amniotic fluid dynamics and the enigma of isolated oligohydramnios.

Traditionally, oligohydramnios has been implemented as a sign of potential fetal compromise and associated with an increased incidence of adverse perinatal morbidity and mortality. Decreased amniotic fluid volume is especially of concern when it occurs in conjunction with structural fetal anomalies, fetal growth restriction, postdates pregnancies, and maternal disease. Consequently, following ultrasonographic diagnosis of oligohydramnios at term, delivery is routinely advocated even in otherwise uncomplicated pregnancies with an appropriate-for-gestational-age fetus, irrespective of the presence of reassuring fetal evaluation and the absence of maternal disease. Numerous factors complicate the ultrasonographic diagnosis of oligohydramnios. These include a lack of complete detailed understanding of the physiology of the dynamics of oligohydramnios, the transient condition at times of decreased amniotic fluid volume, generally poor performance of ultrasonography in detecting oligohydramnios, an array of different ultrasound diagnostic criteria, and varying ultrasonographic thresholds. In light of the latter and the lack of prospective randomized data, is unclear that the practice of effecting delivery for isolated oligohydramnios at term is justified. This article presents physiologic dynamics of amniotic fluid, factors that may affect amniotic fluid volume, possible pitfalls in the ultrasonographic assessment of amniotic fluid volume, and the clinical significance of oligohydramnios. In addition, the literature regarding perinatal outcome associated with oligohydramnios and current available data supporting expectant noninterventional management of cases complicated by isolated oligohydramnios at term are discussed.

Amniotic Fluid↗
PubMed1994

Levels of insulin-like growth factor-binding protein-2 and insulin-like growth factor-II in maternal serum, amniotic fluid and extraembryonic coelomic fluid at 9-20 weeks of pregnancy.

Insulin-like growth factor-II (IGF-II) and IGF-binding protein-2 (IGFBP-2) were measured in amniotic fluid, extraembryonic fluid and maternal serum from 20 women with apparently normal first trimester pregnancies prior to termination. A further 111 specimens of amniotic fluid were collected from women at 10-20 weeks of pregnancy. Levels of IGFBP-2 were similar in coelomic fluid and maternal serum. Levels in amniotic fluid were lower than those in serum and coelomic fluid (Mann-Whitney test; P = 0.0002 and P < 0.0001 respectively). The levels of IGF-II were much higher in maternal serum than in coelomic fluid, and higher in the latter than in amniotic fluid (Mann-Whitney test; P < 0.0001 for both situations). The levels of IGFBP-2 were relatively low at 10-11 weeks (medians 19.8 and 61.1 micrograms/l) but thereafter increased to 20 weeks (median 1400 micrograms/l). The levels of IGF-II showed a similar pattern. The findings suggest that the role of IGF-II and IGFBP-2 in the regulation of growth or differentiation of the fetus or of its surrounding membranes may change with advancing pregnancy.

Adult↗