Amniotic Fluid Glucose Levels Research Articles

958 Pre-cerclage amniotic fluid glucose levels, white blood cell count and pregnancy outcomes

958 Pre-cerclage amniotic fluid glucose levels, white blood cell count and pregnancy outcomes

A multivariable prediction model for intra-amniotic infection in patients with preterm labor and intact membranes including a point of care system that measures amniotic fluid MMP-8.

Among patients with preterm labor and intact membranes (PTL), those with intra-amniotic infection (IAI) present the highest risk of adverse perinatal outcomes. Current identification of IAI, based on microbiological cultures and/or polymerase chain reaction amplification of the 16S ribosomal RNA gene, delay diagnosis and, consequently, antenatal management. The aim to of the study was to assess the performance of a multivariable prediction model for diagnosing IAI in patients with PTL below 34.0weeks using clinical, sonographic and biochemical biomarkers. From 2019 to 2022, we prospectively included pregnant patients admitted below 34.0weeks with diagnosis of PTL and had undergone amniocentesis to rule in/out IAI. The main outcome was IAI, defined by a positive culture and/or 16S ribosomal RNA gene in amniotic fluid. Based on the date of admission, the sample (n=98) was divided into a derivation (2019-2020, n=49) and validation cohort (2021-2022, n=49). Logistic regression models were developed for the outcomes evaluated. As predictive variables we explored ultrasound cervical length measurement at admission, maternal C-reactive protein, gestational age, and amniotic fluid glucose and matrix metalloproteinase-8 (MMP-8) levels. The model was developed in the derivation cohort and applied to the validation cohort and diagnostic performance was evaluated. Clinical management was blinded to the model results. During the study period, we included 98 patients admitted with a diagnosis of PTL. Of these, 10 % had IAI. The final model included MMP-8 and amniotic fluid glucose levels and showed an area under the receiver operating characteristic curve to predict the risk of IAI of 0.961 (95 % confidence interval: 0.860-0.995) with a sensitivity of 75 %, specificity of 93.3 %, positive likelihood ratio (LR) of 11.3 and negative LR of 0.27 in the validation cohort. In patients with PTL, a multivariable prediction model including amniotic fluid MMP-8 and glucose levels might help in the clinical management of patients undergoing amniocentesis to rule in/out IAI, providing results within a few minutes.

Glucose level in amniotic fluid as a preclinical marker of chorioamnionitis

The article presents the results of a study amniotic glucose concentration as a potential early indicator of the inflammatory process in the fetal membranes. The main focus was on the analysis of the features of pregnancy and labor in women with premature rupture of membranes (PROM) during full-term and preterm labor according to amniotic fluid glucose levels. Currently, the expectant approach in cases of PROM is widely practiced throughout the world. The objective: to estimate the glucose level in the amniotic fluid as a preclinical marker of chorioamnionitis. Materials and methods. Depending on the glucose concentration in the amniotic fluid at the time of rupture of membranes and the term of rupture of membranes, 97 pregnant women were divided into 4 groups. I and II groups consisted of women with PROM between 24 and 36 weeks and 6 days. In the I group there were 34 pregnant women with a glucose concentration in the amniotic fluid of more than 0.5 mmol/l, and in the II group – 15 pregnant women with the indicator of less than 0.5 mmol/l. III and IV groups included pregnant women with PROM at full-term pregnancy (after 37 weeks). In the III group there were 34 patients with an amniotic glucose concentration of more than 0.5 mmol/l, and in the IV – 14 pregnant women with the indicator of less than 0.5 mmol/l. In all groups, the further course of pregnancy, the time period from the rupture of membranes to the beginning of labor, the need for induction of labor, hyperthermia before the beginning of labor, deviations from the normal course of labor were analyzed (hyperthermia, fetal distress in labor, uterine weakness) and the frequency of operative delivery. Results. The study determined that women with an amniotic glucose concentration below 0.5 mmol/l at the time of hospitalization were more likely to have hyperthermia before and during childbirth. Hyperthermia was most often observed during the first 12 hours after membrane rupture. In addition, these women were more prone to serious birth complications, such as fetal distress, weak labor, and a greater likelihood of needing an operative delivery. Conclusions. 1. A decreased amniotic glucose level less than 0.5 mmol/l is associated with more frequent clinical manifestations of amniotic infection (20% in preterm pregnancies and 14.8% – in full-term pregnancies) than in groups with a glucose content of more than 0.5 mmol/l (8.8% in preterm pregnancies and 5.9% – in full-term pregnancies, p≤0.05). 2. Among patients with a glucose content in amniotic fluid less than 0.5 mmol/l, laboratory manifestations of intra-amniotic infection were detected more often (40% in preterm pregnancies and 42.5% in full-term pregnancies) than among pregnant women with a glucose content of more than 0.5 mmol/l (20% in both full-term and preterm pregnancies, p≤0.05). 3. Determination of the glucose level in amniotic fluid can be considered as an available method of preclinical diagnosis of chorioamnionitis for the individual choice of management tactics in case of premature rupture of the amniotic membranes, which is especially important in premature pregnancy.

Amniotic fluid glucose level in PPROM pregnancies: a glance at the old friend

Introduction To determine the amniotic fluid glucose levels in pregnancies complicated by preterm prelabor rupture of membranes (PPROM) based on the presence of microbial invasion of the amniotic cavity and/or intra-amniotic inflammation. Methods of Study A total of 142 women with singleton pregnancies complicated by PPROM between gestational ages 24 + 0 and 36 + 6 weeks were included. Amniocentesis was performed at the time of admission. The assessments of microbial invasion of the amniotic cavity (using both cultivation and non-cultivation techniques) and intra-amniotic inflammation (amniotic fluid interleukin-6 levels ≥ 3000 pg/mL) were performed on all the women. Based on the presence of microbial invasion of the amniotic cavity and/or intra-amniotic inflammation, the women were further categorized into the subgroups: (i) intra-amniotic infection (the presence of both microbial invasion of the amniotic cavity and intra-amniotic inflammation); (ii) sterile intra-amniotic inflammation (the presence of intra-amniotic inflammation without microbial invasion of the amniotic cavity); (iii) colonization (the presence of microbial invasion of the amniotic cavity without intra-amniotic inflammation); and (iv) negative amniotic fluid (the absence of either microbial invasion of the amniotic cavity or intra-amniotic inflammation). Amniotic fluid glucose levels were assessed using enzymatic reference method with hexokinase. Results There was a difference in the amniotic fluid glucose levels among the women with intra-amniotic infection, sterile intra-amniotic inflammation, colonization, and those with negative amniotic fluid (p < .0001). No difference was found in the amniotic fluid glucose levels between women with intra-amniotic infection and those with sterile intra-amniotic inflammation [infection: median 11.6 mg/dL (0.7 mmol/L) vs. sterile: median 6.3 mg/dL (0.4 mmol/L); p = .41] and between women with colonization and negative amniotic fluid [colonization: median 21.6 mg/dL (1.2 mmol/L) vs. negative: median 23.4 mg/dL (1.3 mmol/L; p = .67]. Women with intra-amniotic infection and sterile intra-amniotic inflammation had lower amniotic fluid glucose levels than women with colonization and with negative amniotic fluid in crude analysis as well as after adjustment for gestational age at sampling. Amniotic fluid glucose level of 10 mg/dL (0.56 mmol/L) was the optimal concentration for the identification of intra-amniotic inflammation in women with PPROM. Conclusions The presence of intra-amniotic inflammation was associated with lower amniotic fluid glucose levels in singleton pregnancies complicated with PPROM. An amniotic fluid glucose level of 10 mg/dL (0.56 mmol/L) was the optimal concentration for the identification of intra-amniotic inflammation in PPROM pregnancies. In the absence of better amniotic fluid markers, amniotic glucose could be used as a marker of intra-amniotic inflammation, with very good specificity in PPROM pregnancies.

Early- or mid-trimester amniocentesis biomarkers for predicting preterm delivery: a meta-analysis

Objective: To determine the value of early- or mid-trimester amniotic fluid levels of interleukin-6 (IL-6), matrix metalloproteinase-8 (MMP-8), and glucose for predicting preterm delivery.Methods: Randomized controlled trials and two-arm prospective, retrospective, cohorts, and case-controlled studies in which patients received early- or mid-trimester amniocentesis for karyotyping, and biomarker testing of the amniotic fluid was performed and delivery data were available were included in the analysis.Results: Outcome measures were the associations of amniotic fluid IL-6, MMP-8, and glucose levels with preterm delivery. Differences in means with 95% confidence intervals (CIs) were calculated. Of 288 articles identified, 14 were included in the meta-analysis with a total of 675 patients who had preterm birth and 2518 patients who had term births. The preterm-delivery group had significantly higher amniotic fluid IL-6 and MMP-8 levels, and a significantly lower glucose level than the term delivery group (IL-6: difference in means = 0.32, 95% CI: 0.22–0.43, p < 0.001; MMP-8: difference in means = 4.47, 95% CI: 0.83–8.11), p = 0.016; glucose: difference in means = −5.22, 95% CI: −8.19 to −2.26, p = 0.001)Conclusion: Early- or mid-trimester amniotic fluid IL-6, MMP-8, and glucose levels are useful for predicting the risk of preterm delivery.KEY MESSAGESMedian amniotic fluid ferritin and IL-6 levels, and mean amniotic fluid ALP levels were higher in the preterm group.The preterm-delivery group had significantly higher amniotic fluid IL-6 and MMP-8 levels, and a significantly lower glucose level than the term-delivery group.

Correlation of glucose concentrations in maternal serum and amniotic fluid in high-risk pregnancies

We sought to determine whether a correlation exists between maternal serum glucose and amniotic fluid glucose in high-risk pregnancies. We conducted a prospective cross-sectional study of 60 patients, between 15 and 38 weeks' gestation, undergoing amniocentesis between March 2006 and April 2007. Participants underwent amniocentesis with evaluation of amniotic fluid glucose and maternal finger stick glucose. Data were collected on maternal demographics, gestational age, presence of diabetes or chorioamnionitis, use of betamethasone, and body mass index. Statistical analyses included Spearman rho correlations. A positive correlation was found between maternal serum glucose and amniotic fluid glucose (r = 0.401, P < .01), and amniotic fluid index and diabetes (r = 0.367, P < .05). An inverse correlation was found between amniotic fluid glucose and chorioamnionitis (r = -0.499, P < .01). Maternal hyperglycemia directly influences amniotic fluid glucose levels and may result in an elevated amniotic fluid glucose value.

Are amniotic fluid C-reactive protein and glucose levels, and white blood cell counts at the time of genetic amniocentesis related with preterm delivery?

To compare women with spontaneous preterm delivery before 37 weeks and women who delivered at term with respect to amniotic fluid C-reactive protein (CRP), glucose levels, and white blood cell counts at the time of genetic amniocentesis. The study was conducted on 216 pregnant women who underwent genetic amniocentesis between the 15th and 18th weeks of gestation at Baskent University Obstetrics and Gynecology Department. All patients were followed until delivery for the occurrence of pregnancy complication. Indications for amniocentesis included abnormal triple test results showing increased risk for Down's syndrome, advanced maternal age and sonographic findings indicative for chromosomal abnormalities. The samples were carried immediately to the laboratory for cytogenetic and biochemical examination. Women with spontaneous preterm delivery before 37 weeks (n = 20) and those who delivered at term (n = 196) were compared with respect to some maternal and infant characteristics, amniotic fluid C-reactive protein, glucose levels, and amniotic fluid white blood cell counts. During the study period 244 patients underwent amniocentesis. A chromosomal abnormality was present in 11 patients. 1 patient had a spontaneous pregnancy loss within 3 weeks after the procedure and 16 patients were delivered for fetal or maternal indications (preeclampsia, fetal growth restriction, placenta previa). The remaining 216 women were included in the study and investigated for the risk of preterm delivery. The prevalence of spontaneous preterm delivery before 37 weeks was 9.3% (20/216). There were no significant differences between the preterm delivery and the term delivery groups with respect to C-reactive protein levels and white blood cell counts. Mean amniotic glucose levels were significantly lower in the preterm delivery group (P<0.05). Amniotic fluid glucose levels of < or = 46 mg/dL had a sensitivity of 100% and NPV of 100%. Amniotic fluid glucose levels at the time of genetic amniocentesis are lower in women with spontaneous preterm delivery before 37 weeks compared to those who delivered at term. Amniotic fluid glucose levels of < or = 46 mg/dL at the time of genetic amniocentesis may be more sensitive, cheaper and have higher negative predictive value than C-reactive protein levels and white blood cell counts for the prediction of patients in spontaneous preterm labor. The greatest benefit of amniotic fluid glucose testing might be when the physician judges the patient to be at low risk for preterm delivery.

Amniotic fluid glucose at the time of genetic amniocentesis: correlation with duration of pregnancy and birthweight

Objective: To test whether amniotic fluid (AF) glucose levels in 15–18 weeks of pregnancy can predict birthweight and duration of pregnancy. Study design: In this prospective study, 66 non-diabetic pregnant women underwent amniocentesis between 15 and 18 weeks of pregnancy and glucose levels were measured immediately by using the enzymatic method of hexocinase. They were all followed up and delivered in our department and neognological parameters were recorded. Results: AF glucose values ranged from 12 to 69 mg/dl (mean 44.2 mg/dl, S.D. 11.6 mg/dl). No linear relationship was found between AF glucose and either birthweight or duration of pregnancy. Conclusion: AF glucose values between 15 and 18 weeks of pregnancy did not correlate with either birthweight or duration of pregnancy. A single measurement of this value cannot be used for the prediction of the factors studied.

Correlation between amniotic fluid glucose concentration and amniotic fluid volume in pregnancy complicated by diabetes

Objective: Pregnancies complicated by diabetes are frequently characterized by an increased volume of amniotic fluid, and the pathophysiologic mechanism of this increase is not known. Our goal was to evaluate the relationship between amniotic fluid glucose concentration and the amniotic fluid index in pregnancies complicated by insulin-treated diabetes and to compare it with that seen in normal pregnancies. Study Design: Amniotic fluid index and amniotic fluid glucose levels were measured before elective repeated cesarean delivery in 41 women with insulin-treated diabetes and in 35 women without diabetes. Only singleton gestations without anomalous fetuses were included. Women with diabetes were hospitalized for approximately 4 weeks before delivery, during which time glycemic control was optimized. Amniotic fluid index and amniotic fluid glucose concentration were correlated with each other and were compared between the groups with and without diabetes. Results: The mean amniotic fluid index was significantly increased in the diabetes group (16.6 ± 5.0 cm in the diabetes group vs 13.4 ± 3.5 cm in the control group; P = .002). The amniotic fluid glucose concentration was also significantly greater in the diabetes group than in the control group (39 ± 17 mg/dL in the diabetes group vs 24 ± 11 mg/dL in the control group; P < .001). Among women with diabetes the amniotic fluid glucose concentration was significantly correlated with the amniotic fluid index ( r = 0.32; P = .04), a correlation not found among the control women. The mean fasting blood glucose concentration among the women with diabetes for the week before amniocentesis was 82 ± 11 mg/dL. Conclusion: The amniotic fluid index parallels the amniotic fluid glucose level among women with diabetes. This finding raises the possibility that the hydramnios associated with diabetes is a result of increased amniotic fluid glucose concentration. (Am J Obstet Gynecol 2000;182:901-4.)

Amniotic fluid matrix metalloproteinase-9 levels in women with preterm labor and suspected intra-amniotic infection

Objective: To determine the accuracy of amniotic fluid (AF) matrix metalloproteinase-9 measurements for diagnosing intra-amniotic infection in women with preterm labor. Methods: We performed amniocenteses in 44 women between 22 and 35 weeks’ gestation who presented to our center with preterm labor and clinical suspicion of intra-amniotic infection. Each sample was analyzed by glucose measurement, Gram stain, and culture for aerobes, anaerobes, and mycoplasmas. We tested the AF for matrix metalloproteinase-9 using gelatin zymography and a commercial enzyme-linked immunosorbent assay (ELISA) system. We calculated accuracy and confidence intervals (CIs) for AF matrix metalloproteinase-9, glucose, and Gram stain for diagnosing intra-amniotic infection, using culture as the criterion standard. Results: All patients who had matrix metalloproteinase-9 detectable by ELISA also demonstrated matrix metalloproteinase-9 by zymography. Six cases of intra-amniotic infection were confirmed by culture (prevalence 14%). The performance statistics of AF matrix metalloproteinase-9 for diagnosing intra-amniotic infection were: sensitivity 83% (95% CI 53, 99), specificity 95% (95% CI 88, 99), positive predictive value 71% (95% CI 37, 99), and negative predictive value 97% (95% CI 92, 99). Two women had false-positive results; one had gram-negative rods on the AF Gram stain and developed clinical signs and symptoms of chorioamnionitis several hours after amniocentesis and the other had a purulent vaginal discharge and an AF glucose level less than 15 mg/dL. Both delivered within 24 hours of amniocentesis. Conclusion: Measuring matrix metalloproteinase-9 in the AF appeared to be reliable for diagnosing intra-amniotic infection. An elevated matrix metalloproteinase-9 concentration in the AF at a preterm gestational age may portend imminent delivery regardless of microbiologic confirmation of intra-amniotic infection.

Nitric oxide: a clinically important amniotic fluid marker to distinguish between intra-amniotic mycoplasma and non-mycoplasma infections.

The objective of this study was to determine whether the measurements of amniotic fluid nitric oxide metabolite (NOx: nitrate + nitrite) concentrations could be a clinically useful marker to differentiate between intra-amniotic mycoplasma and nonmycoplasma infections. Amniocentesis was performed on 76 pregnant women with suspicion of intra-amniotic infection. Intra-amniotic infection was defined as the presence of a positive amniotic fluid culture with either mycoplasma or nonmycoplasma infections. Rapid amniotic fluid tests for Gram stain, glucose, leukocyte counts, interleukin-6, and NOx were performed. Amniotic fluid NOx was measured with aspergillus nitrate reductase and Griess reagent. Interleukin-6 was determined by enzyme immunoassays. Amniotic fluid NOx and interleukin-6 were normalized by amniotic fluid creatinine levels. Patients with intra-amniotic mycoplasma (n = 7) and nonmycoplasma infections (n = 8) had significantly higher amniotic fluid leukocyte counts and interleukin-6 concentrations and significantly lower amniotic fluid glucose levels than noninfected controls (n = 61). Amniotic fluid concentrations of NOx were significantly higher in those with intraamniotic nonmycoplasma infection as compared to those with intraamniotic mycoplasma infection and noninfected controls (NOx: 3.35+/-0.74 vs. 2.03+/-0.41 micromol/mg creatinine, p = 0.005, and 3.35+/-0.74 vs. 1.72+/-0.07 micromol/mg creatinine, p < 0.0001, respectively). However, patients with intra-amniotic mycoplasma infection did not differ significantly from noninfected controls. Our data indicate that clinical characteristics of intra-amniotic mycoplasma infection may differ from intra-amniotic nonmycoplasma infection. As delivery is not always indicated in intra-amniotic mycoplasma infection, elevated rapid amniotic fluid tests (leukocyte counts, interleukin-6, and glucose) may not be appropriate in the clinical management of intra-amniotic mycoplasma infection. In addition to these rapid amniotic fluid tests, incorporation of the measurement of amniotic fluid NOx may be of clinical importance in the differentiation and management of patients with suspected intra-amniotic mycoplasma and nonmycoplasma infection.

Evaluating rapid diagnostic tests of intra-amniotic infection: Gram stain, amniotic fluid glucose level, and amniotic fluid to serum glucose level ratio

OBJECTIVE: The aim of the study was to compare the diagnostic utility of the Gram stain, the amniotic fluid glucose level, and the ratio of amniotic fluid glucose level to serum glucose level in detecting intra-amniotic infection. STUDY DESIGN: We conducted a prospective study of 127 patients with preterm labor and 26 patients with preterm premature rupture of the membranes (153 total). All patients underwent amniocentesis to diagnose intra-amniotic infection. The diagnostic criterion for intra-amniotic infection was a positive amniotic fluid culture result. RESULTS: The Gram stain is 80% sensitive and 91% specific when a positive is considered the presence of white blood cells or bacteria. Amniotic fluid glucose level and the ratio of amniotic fluid glucose level to serum glucose level are significantly lower when amniotic fluid culture results are positive, but as diagnostic tests they are inferior to the Gram stain. Logistic regression models that combine predictors yield superior accuracy with respect to individual tests. The most accurate combination was amniotic fluid glucose level and Gram stain with white blood cells or bacteria. Although the number of patients with preterm premature rupture of the membranes was small in this study ( n = 26), analysis of our data suggests that the diagnostic performance levels of these tests were similar when used in patients with preterm labor and intact membranes and in patients with premature rupture of the membranes. CONCLUSIONS: The amniotic fluid glucose level and the ratio of amniotic fluid to serum glucose level have equivalent diagnostic utility and are inferior to the Gram stain. The combination of Gram stain with amniotic fluid glucose level is superior to any individual test. (Am J Obstet Gynecol 1998;179:650-6.)

Accuracy of portable glucose meters for rapid determination of amniotic fluid glucose levels

This study was designed to evaluate the accuracy and feasibility of use of three commercially available portable blood glucose meters to measure amniotic fluid glucose(AFG) levels as compared to an accepted laboratory standard. A prospective study of amniotic fluid from 101 consecutive amniocenteses was performed. Glucose concentration in the amniotic fluid was assessed by hexokinase method in our hospital laboratory (control) and by using three portable meters: Advantage (ADV) (Boehringer Mannheim), Glucometer Elite (ELT) (Bayer), and One Touch II Hospital (T-2) (Lifescan). Twenty consecutive amniotic fluid samples were sent to the laboratory in two vials, the first without additive and the second with potassium oxalate to prevent metabolic activity, to assess the effect of cellular metabolism and time delay on amniotic fluid glucose concentrations. Data are reported as mean ±SE and were assessed by one-way ANOVA. Of the 101 patients studied, 29 were of gestational age ≥20 wks. The remaining 72 patients were <20 wks. All three ambulatory meters demonstrated a linear relationship with control (all P < 0.001). Given a slope of almost 1.0 (m = 0.94) and a y-intercept approaching zero (b = 4.3), the OT2 proved to correlate best with control. ELT: (r2 = 0.55, m = 0.79, b = 22.2) and ADV: (r2 = 0.74, m = 1.45, b = 16.9) both overestimated amniotic fluid glucose. When AFG was <30 mg/dl via laboratory standard, OT2: (r2 = 0.78, m = 1.05, and b = −2.20, P < 0.001), ADV: (m = 1.02, b = 24.1, r2 = 0.12, P = 0.133). The One Touch II Hospital accurately predicted amniotic fluid glucose at the bedside with excellent correlation including with laboratory standard glucose levels <30 mg/dl. ADV and ELT proved too inaccurate for clinical use. Control samples were not affected by additives or time delay. These findings confirm that AFG determinations can be obtained rapidly with the OT2 meter at the bedside. J. Matern.-Fetal Med. 7:183–189, 1998. © 1998 Wiley-Liss, Inc.

Accuracy of portable glucose meters for rapid determination of amniotic fluid glucose levels

This study was designed to evaluate the accuracy and feasibility of use of three commercially available portable blood glucose meters to measure amniotic fluid glucose(AFG) levels as compared to an accepted laboratory standard. A prospective study of amniotic fluid from 101 consecutive amniocenteses was performed. Glucose concentration in the amniotic fluid was assessed by hexokinase method in our hospital laboratory (control) and by using three portable meters: Advantage (ADV) (Boehringer Mannheim), Glucometer Elite (ELT) (Bayer), and One Touch II Hospital (T-2) (Lifescan). Twenty consecutive amniotic fluid samples were sent to the laboratory in two vials, the first without additive and the second with potassium oxalate to prevent metabolic activity, to assess the effect of cellular metabolism and time delay on amniotic fluid glucose concentrations. Data are reported as mean ±SE and were assessed by one-way ANOVA. Of the 101 patients studied, 29 were of gestational age <20 wks. The remaining 72 patients were < 20 wks. All three ambulatory meters demonstrated a linear relationship with control (all P < 0.001). Given a slope of almost 1.0 (m = 0.94) and a y-intercept approaching zero (b = 4.3), the OT2 proved to correlate best with control. ELT: (r2 = 0.55, m = 0.79, b = 22.2) and ADV: (r2 = 0.74, m = 1.45, b = 16.9) both overestimated amniotic fluid glucose. When AFG was < 30 mg/dl via laboratory standard, OT2: (r2 = 0.78, m = 1.05, and b = -2.20, P < 0.001), ADV: (m = 1.02, b = 24.1, r2 = 0.12, P = 0.133). The One Touch II Hospital accurately predicted amniotic fluid glucose at the bedside with excellent correlation including with laboratory standard glucose levels < 30 mg/dl. ADV and ELT proved too inaccurate for clinical use. Control samples were not affected by additives or time delay. These findings confirm that AFG determinations can be obtained rapidly with the OT2 meter at the bedside.

Amniotic fluid granulocyte colony stimulating factor levels: a rapid marker for diagnosing chorioamnionitis.

To assess the usefulness of amniotic fluid (AF) granulocyte colony stimulating factor (G-CSF) levels as a rapid marker for diagnosing chorioamnionitis. AF levels were obtained from term and preterm patients with and without chorioamnionitis (CAM). Patients with urinary tract, respiratory tract, and other infections were excluded. Results obtained from the AF G-CSF assays were compared with those from other parameters used for diagnosing CAM: maternal fever, leukocytosis, tachycardia, fetal tachycardia, AF glucose levels, white blood cell count, Gram stain, and aerobic and anaerobic cultures. The sensitivity, specificity, and predictive values were calculated. In the uninfected AF samples, G-CSF levels were present but low, ranging from 400 to 1600 pg/ml. Levels in the infected samples, however, were markedly increased, ranging from 1600 to 14,000 pg/ml; P < 0.05. When a cutoff of 2000 pg/ml was used as a clear marker for CAM, the sensitivity was 67%, the specificity was 100%, and the positive and negative predictive values were 100% and 86%, respectively. The comparison of the other AF G-CSF laboratory parameters also revealed high sensitivity, specificity, and predictive values for detecting CAM. (i) AF G-CSF levels are elevated in CAM. (ii) An AF G-CSF level > 2000 pg/ ml is a strong positive predictor of CAM. (iii) Elevated AF G-CSF levels appear to be more reliable in predicting CAM than any other single test currently used in clinical practice.

THE RELATIONSHIP BETWEEN SECOND-TRIMESTER AMNIOTIC FLUID INSULIN AND GLUCOSE LEVELS AND SUBSEQUENT GESTATIONAL DIABETES

Associations between elevated amniotic fluid glucose and insulin levels in the second trimester and the subsequent development of gestational diabetes have been reported. We conducted a case-control study to determine which analyte best predicts future maternal glucose intolerance. Thirty-nine women diagnosed with gestational diabetes (criteria of Carpenter and Coustan, Am. J. Obstet. Gynecol., 144, 768, 1982) who had undergone genetic amniocentesis for advanced maternal age were matched with euglycaemic controls. Glucose and insulin concentrations were determined by analysis of stored amniotic fluid samples. No significant difference was detected between cases and controls for amniotic fluid glucose concentrations. Amniotic fluid insulin concentrations were significantly higher in cases (mean rank 4.44, P < 0.01, using matched rank analysis of variance, where 1 is the lowest and 6 is the highest rank). After conversion to multiples of the median, 20 per cent of women with subsequent gestational diabetes were found to have amniotic fluid glucose levels at or above the 90th centile, while 35 per cent of cases had similarly elevated amniotic fluid insulin levels. We conclude that second-trimester amniotic fluid insulin is a more sensitive predictor of impending glucose intolerance than amniotic fluid glucose, although neither is sufficiently powerful to use alone as a screening test.

Accuracy of portable glucose meters for the determination of amniotic fluid glucose levels

Accuracy of portable glucose meters for the determination of amniotic fluid glucose levels

Low amniotic fluid glucose levels are a specific but not a sensitive marker for subclinical intrauterine infections in patients in preterm labor with intact membranes

The purpose of this study was to evaluate the ability of a low amniotic fluid glucose level, as defined by previously published thresholds, to identify a subclinical intrauterine infection in women in preterm labor with intact membranes. Amniotic fluid glucose levels, amniotic fluid cultures, and placental histologic characteristics were determined in women with preterm labor (n = 55) and in preterm controls (n = 58). These amniotic fluid glucose levels were compared between women with and without intrauterine infection using the Mann-Whitney U test. The sensitivity, specificity, and positive and negative predictive values for the identification of an intrauterine infection were determined with four different previously published amniotic fluid glucose threshold levels and the threshold from receiver-operator characteristic curve analysis of the study data. The median amniotic fluid glucose level was significantly lower in patients with positive amniotic fluid cultures (intraamniotic infection group) but was not lower in the group of patients with only histologic chorioamnionitis (extra-amniotic infection group), compared with noninfected controls. The sensitivity of a low amniotic fluid glucose level to detect both types of intrauterine infection ranged from 41% to 55%, depending on the threshold used. The specificity of a low amniotic fluid glucose level to detect an intrauterine infection ranged from 94% to 100%, the positive predictive value ranged from 86% to 100%, and the negative predictive value ranged from 70% to 80% with the same thresholds. Low amniotic fluid glucose levels are a specific but not a sensitive marker for either intraamniotic or extra-amniotic intrauterine infections in patients with preterm labor.

Glucose causes lengthening of the microvilli of the neural plate of the rat embryo and produces a helical pattern on their surface.

Prominent microvilli have been observed on the surface of neural plates in the embryos of many species. Since glucose is the main source of energy for embryos before neural tube closure and the onset of vascular circulation, it was of interest to study the relationship between these microvilli and glucose utilization in the neural plate. By applying microdrops of amniotic fluid to chemstrips, which colorimetrically measure glucose by glucose oxidase reaction, we determined that day 10 rat amniotic fluid glucose level was 31.6 +/- 1.6 mg/dl. On day 10 and within about 20 min from removal of the decidual sites, no glucose was found in the amniotic fluid. By use of a scanning electron microscope, the microvilli of the day 10 neural plate were found to have a 10-fold increase in length during a 40-min exposure to Hanks' solution at 21-23 degrees C. Similarly exposed embryos in Hanks' without glucose did not have microvillus elongation. However, under whole embryo culture conditions at 38 degrees C no extension of the microvilli was found. In the closed neural tube of the day 10 embryo, the microvilli were stubby and did not elongate with glucose exposure. Similarly, day 11 and 14 embryos had short microvilli which did not elongate with direct exposure to glucose at 21-23 degrees C. The short microvilli on the surface of the closed neural tube on day 11, 14, and 16 were associated with low glucose concentrations in the neural tube fluids. By use of a field emission scanning electron microscope, the surfaces of the microvilli in the extended position were seen to be covered by a right-handed helical array of globular objects the size of large molecules. The findings support the hypothesis that microvillar length may modulate glucose uptake. Shortening is associated with low concentrations of glucose in closed neural tubes, and lengthening occurs at glucose exposures of 100 mg/dl.

The temporal relationship between maternal blood and amniotic fluid glucose levels

Our purpose was to examine the temporal relationship between maternal blood and amniotic fluid levels. Glucose levels were measured on 158 paired samples from maternal plasma and amniotic fluid obtained from healthy women undergoing genetic amniocentesis at 15 to 20 weeks of gestation. The samples of venous blood and amniotic fluid were drawn at different time intervals, randomly assigned from 0 to 200 minutes. Linear regression analysis was used to test the relationship. The significance was tested by two-tailed t test. A good significant correlation (r = 0.78, p < 0.01 and r = 0.67, p < 0.05) was found at 21- to 40- and 121- to 140-minute intervals, respectively. The amniotic fluid glucose level reflects the maternal blood glucose levels at specific lag times.