Amniotic Fluid Optical Density Research Articles

Amniotic Fluid Optical Density in Spontaneous Onset of Labor and Elective Termination of Pregnancies beyond 34 Weeks of Gestation and Its Correlation with Neonatal Outcome

Amniotic Fluid Optical Density in Spontaneous Onset of Labor and Elective Termination of Pregnancies beyond 34 Weeks of Gestation and Its Correlation with Neonatal Outcome

Comparison of outcomes of Foley's induced labors with different sonographic floater densities in fore-water

Background: Onset of spontaneous labor occurs on completion of fetal functional maturity at amniotic fluid optical density (AFOD) 0.98 ± 0.27 (mean ± SD). All three events occurring together at any time from 35 weeks to 42 weeks indicate the individualized term for each fetus. No failures of induction of labor were reported when labors induced at AFOD 0.98 ± 0.27. As AFOD estimation needs invasive amniocentesis, we tried to induce women with liquor with mature AFOD by observing the sonographic appearances of fore-water by transvaginal sonography. Methods: In this comparative study, three groups of gestational age and parity matched uncomplicated singleton term pregnant women, underwent fore-water trans-vaginal sonography before induction of labor with Foley's catheter. Sonographic images were divided into three grades based on floating particle densities. Each group consisted of 20 women with each grade of sonographic images. Uncentrifuged fresh AF samples collected at amniotomy were used for AFOD measurement with colorimeter at 650 nm in all groups. After Foley's expulsion, labor was augmented with vaginal misoprostol. The mean AFOD values, Foley's insertion expulsion intervals, Foley's insertion delivery intervals (FIDI), T misoprostol required, and neonatal respiratory distress were recorded in each group and compared. Results: In groups 1, 2, and 3, the mean AFOD was found to be 0.29 ± 0.09, 0.68 ± 0.14, and 1.15 ± 0.20, respectively. Mean Foley's insertion expulsion intervals were 10.57 ± 3.76 h, 5.83 ± 2.24 h, and 4.08 ± 0.86 h, respectively. Mean FIDI were 20.00 ± 6.20 h, 11.22 ± 4.20 h, and 8.95 ± 2.98 h, respectively. The mean numbers of T misoprostol required in each group was 3 ± 1, 2 ± 1, and 2 ± 1, respectively. Significant differences were observed in all outcomes between groups (P Conclusion: Labor induction with Grade 3 sonographic images of fore-water was successful in all women with shorter FIDI, and with better perinatal outcomes.

Outcomes of induction of labor with mature and premature amniotic fluid optical density (AFOD): A preliminary case control study

Background: Onset of spontaneous labor occurs on completion of fetal functional maturity at amniotic fluid optical density (AFOD) value 0.98 ± 0.27 (Mean ± SD). All three events occurring together at any time from 35 to 42 weeks indicate individual term for each fetus. Babies born with AFOD ≤0.40 are functionally premature and develop varying degrees of respiratory distress syndrome (RDS). In this study, we tested the hypothesis, labors with AFOD 0.98 ± 0.27 are functionally mature with well-established labor cascades and may respond well t o induction. On the other hand, labors with AFOD ≤0.40 are functionally premature with poorly established labor cascades and may not respond well t o induction. Methods: In this gestational age and parity-matched case control study, cases consisted of 36 uncomplicated singleton laboring women who delivered normally with premature (≤0.40) AFOD values. Controls consisted of 36 similar laboring women who delivered normally with mature AFOD (0.98 ± 0.27) values. Uncentrifuged fresh AF samples collected at amniotomy were used for OD measurement with colorimeter at 650 nm. Women were assigned to groups based on AFOD values. In both groups, labor was induced with vaginal T. Misoprostol 25 mcg 6 hourly up to 4 doses. Labor outcome measures; Bishop score at induction, induction- delivery intervals (IDI), induction failures, number of T. Misoprostol required, presence of fetal distress, RDS, and NICU admission days were recorded in both groups and compared. Results: Median Bishop scores at induction in cases and controls were 5.0 (IQR 4.25--6), 7.0 (IQR 6--8), respectively. Median IDI in cases and controls were 18 h (IQR 12.25--21.5 h) and 7.0 h (IQR 5--9.5 h), respectively. Number of induction failures in cases and controls were 8 and 0, respectively. Outcomes of Induction of labor with…. Statistically significant differences observed in all these outcomes between groups (P = 0.00) favoring inductions with mature AFOD. Conclusion: Labor induction with mature AFOD value was successful in all women with shorter IDI and with better perinatal outcomes.

Role of Amniotic Fluid Optical Density (AFOD) and Low dose Isoxsuprine Hcl rapid infusion tocolysis for the management of PTL

Background:S.Ramet.al reported: Onset of spontaneous labor occurs at completion of fetal functional maturity at AFOD value of 0.98±0.27 (at 650nm). All these events together occurring at any time from 35+wks to 42+wks indicateindividual term for each fetus .Preterm labors with AFOD 0.98±0.27 are mature and cannot be stopped by any means, as labor cascades are already established. Babies born with AFOD <0.40 arefunctionally premature , and we expected thesepremature laborswouldrespond well for tocolysis and other methods for continuation of pregnancies as labor cascades are not fully established. Methods:In thiscase series study, 22 singleton pregnant women who were inpreterm labor (PTL),and who underwent CRL gestational age estimations, 5 of them PTL with membrane rupture and17 without membrane rupture were included. USG guided amniocentesis was performed as per the ACOG guidelines, and AFOD estimations were done for fresh uncentrifuzed samples. Antenatal corticosteroids, low dose Isoxsuprine Hcl rapid infusion tocolysis, and weekly 17-alphahydroxy progesterone caproate were given. After successful tocolysis and continuation of pregnancies, AFOD estimations were repeated when women presented with labor pains again before 37w+6days. Women were allowed to deliver if mature or near mature AFOD values were observed. AFOD estimations were also done at spontaneous labor or at caesarean sections after 38wks. Babies were observed for functional maturity in terms of color of skin, adherence of vernix, and development of RDS. Results were presented in two tables and analyzed. Results:In non-membrane rupture group (N=17), pregnancies could be continued for 1 to 7 wks. In membrane rupture group, in N=2/5 women leak could be stopped and pregnancies could be continued for 3 to 6 wks. Except one, in both groups all babies could attain mature or near mature AFOD values irrespective of GA and birth weight,noRDS was observed, and all babies survived. Conclusion:WithAFOD guided PTL management coupled with low dose Isoxsuprine Hcl rapid infusion tocolysis, pregnancies could be continued to completion of fetal functional maturity in 21/22 women with good neonatal outcome.

Correlation between Amniotic Fluid Optical Density (AFOD) and functional maturity status of the newborn at caesarean delivery in GDM

Objective: To observe the correlation between Amniotic Fluid Optical Density (AFOD) and functional maturity status of the newborn at caesarean delivery in 16 women with Gestational Diabetes Mellitus (GDM). Methods: Amniotic Fluid (A.F) samples were collected while doing caesarean sections around 38+wks CRL gestation. Uncentrifuged fresh AF samples were used for AFOD estimations with colorimeter at 650nm. HbA1c estimations were done for all women just before caesarean sections. These women received antenatal steroids as per the RCOG guidelines 1 . Babies were evaluated for functional maturity status in terms of APGAR scores, development of RDS after 5mnts, adherence of vernix on skin surface, and color of the skin. Birth weights were recorded by electronic weighing machine. Results:Fourteen of these 16 women, were observed to have mature AFOD values (0.98±0.27), at differentgestational ages (GA)ranging from 36w+6d to 39w+6d 2, 3 . Twelve of these 14 women had good glycemic control with HbA1c values between 5.1 and 5.6.Two women had poor glycemic control with HbA1c values 7.0 and 7.1. All these babies were fully functionally mature, and their skin was mature pale brown in color with very little vernix, and none of them developed RDS.Birth weights ranged from 2.6kg to 3.9kgs. Two women had premature AFOD values (<0.40) 2, 3 at 36w+6d and 40wks gestation. Their glycemic control was good with HbA1c values 5.4 and 5.6 respectively. Both these babies had plenty of vernix caseosa on skin surface, and developed severe RDS with in 5mnts after delivery which required invasive and noninvasive ventilation support and surfactant therapy. Conclusion: The concept of ‘individual term for each fetus’ 4 is also applicable in women with GDM. AFOD value 0.98±0.27 assures functionally mature babies who do not develop RDS irrespective of GA and glycemic control.Babies born with AFOD values<0.40 are functionallypremature irrespective of GA and arelikely to develop RDS which may require ventilator support.

Role of Echogenic Amniotic Fluid Particles and Optical Density in prediction of Respiratory Distress Syndrome and Labor

This study was aimed to correlate echogenic amniotic fluid particle size (AFPS) in late third trimester to fetal lung maturity and amniotic fluid optical density (AFOD) at labor. AFPS were measured with specified criteria by real time transabdominal USG (3.5MHz) while Amniotic Fluid Index (AFI) was measured during routine antenatal visits. The criteria for AFPS score which are taken into account are the amniotic fluid particle size, number and distribution. Serial AFPS measurements were done till onset of labor. AFPS was correlated to AFOD value at spontaneous labor in 123 women. Uncentrifuged fresh amniotic fluid samples were obtained during ARM/amniotomy and used for AFOD estimation at 650 nm. The mean AFPS and AFOD at onset of labor was found to be 5.14 ± 0.69 mm (3.67 – 6.7 CI 95%) and 1.03 ± 0.31 (0.35 -1.69 CI 95%) respectively in 116 women who delivered normal babies devoid of respiratory distress syndrome (RDS). Serial AFPS measurements showed a definite AFOD surge after a value in the region of 3.8 mm which is obtained culminating in onset of Labor. 28 women (24.1%) had dense clusters of free floating particles across the vertical pool in amniotic fluid with mean AFPS and AFOD of 5.6 ± 0.68 mm and 1.12 ± 0.21 respectively. In 123 women, AFPS < 3.8 mm had sensitivity of 85.74% and positive predictive value of 66.67% in predicting RDS. AFPS serves as a sonological marker for fetal lung maturity and labor. The range of AFOD values can be measured in terms of AFPS (r =0.6, F = 69.8, β= + 0.23, p < 0.001). Serial AFPS estimation predicts fetal maturity and onset of labor.KEY WORDS: Amniotic fluid; Particle size; Optical density; Respiratorydistress syndrome; Labor

Amniotic Fluid Particles and Optical Density at Term - A Case Report

We report a case of pregnancy at full term and transabdominal ultrasonography (USG) revealed minute amniotic fluid particles prior to onset of spontaneous labor. Amniotic Fluid Optical Density (AFOD) estimation for fetal lung maturity was done. AFOD was 0.43 in uncentifuged and 0.14 in centrifuged samples at 650 nm. USG at onset of labor detected amniotic fluid particles of 3-4 mm size corresponding to AFOD of 1.40 (uncentrifuged sample) at ARM. The rapid increase in the size of the echogenic amniotic fluid particles simultaneously with optical density may be able to serve as an index of physiological process that contributes to the onset of labor.

A comparison between middle cerebral artery peak systolic velocity and amniotic fluid optical density at 450 nm in the prediction of fetal anemia

Objective: The purpose of this study was to compare fetal middle cerebral artery peak systolic velocity with amniotic fluid delta optical density at 450 nm in the prediction of fetal anemia. Study Design: A prospective study that involved 28 singleton pregnancies that were at-risk for fetal anemia was carried out in a tertiary teaching hospital. Middle cerebral artery peak systolic velocity was measured immediately before the determination of Δoptical density at 450 nm and fetal hemoglobin concentration. Sensitivities and predictive values for fetal anemia were examined. Results: Fetal hemoglobin concentrations correlated significantly with middle cerebral artery peak systolic velocity (correlation coefficient, −0.77; P < .0001) and Δoptical density at 450 nm zones (correlation coefficient, −0.56; P = .0025). Middle cerebral artery peak systolic velocity was >1.5 multiples of the median in 15 of 28 cases (54%); for this cutoff value, the sensitivity and positive-predictive values for a hemoglobin deficit of >−3SD were 75% and 60% and for a hemoglobin deficit of >−5SD were 100% and 47%, respectively. The corresponding values for Δoptical density at 450-nm zone III (6/28 cases, 21%) were 0% (hemoglobin deficit, <−3SD) and 86% and 100% (hemoglobin deficit, <−5SD). Conclusion: Middle cerebral artery peak systolic velocity and amniotic fluid optical density at 450 nm are both useful in the prediction of fetal anemia. However, Doppler examination has the advantage of being a noninvasive method that can help reduce the number of invasive procedures in pregnancies that are at-risk for fetal anemia. (Am J Obstet Gynecol 2003;188:214-9.)

Can a single measurement of amniotic fluid delta optical density be safely used in the clinical management of Rhesus‐alloimmunized pregnancies before 27 weeks' gestation?

To assess the efficacy of a single measurement of amniotic fluid optical density deviation at 450 nanometers in predicting fetal anemia in Rhesus-alloimmunization before 27 weeks gestation. In this cross-sectional study, fetal blood and amniotic fluid samples from 43 Rhesus-alloimmunized pregnancies at 18 to 26 weeks gestation were obtained under ultrasound guidance. Amniotic fluid samples were scanned by spectrophotometry for optic density at various wavelengths. Deviation at 450 nanometers was calculated between 550 and 365 nanometers. The fetuses were divided into three groups based on their hematocrit levels and the predictive efficacy of optic density zones for anemia was evaluated. A high number of false positive and false negative results were observed when the delta-amniotic fluid optical density of fetuses at risk for anemia was plotted to the zones recently proposed to manage Rhesus-alloimmunized pregnancies. These data confirm previous results that the diagnosis of fetal anemia in Rhesus-alloimmunized pregnancies before 27 weeks' gestation cannot be accurately made by a single measurement of amniotic fluid optical density at 450 nanometers.

Second-trimester echogenic bowel and intraamniotic bleeding: Association between fetal bowel echogenicity and amniotic fluid spectrophotometry at 410 nm

OBJECTIVE: Our purpose was to determine whether the presence of heme pigments in amniotic fluid is associated with the ultrasonographic findings of increased fetal bowel echogenicity in the second trimester. STUDY DESIGN: Spectrophotometric analysis of amniotic fluid for optical density at 410 nm was prospectively performed to study the presence of heme pigments in (1) 104 pregnancies undergoing second-trimester amniocentesis for routine cytogenetic indications and (2) in 14 pregnancies undergoing amniocentesis for prenatal karyotyping because of fetal strongly echogenic bowel. In the routine amniocentesis group the fetal small bowel echogenicity was assessed immediately before amniocentesis and classified as nonechogenic ( n = 64), mildly echogenic ( n = 36), or hyperechogenic ( n = 4) with the fetal iliac wing and liver used as references. Only amniotic fluid specimens that were obtained at the first attempt and that were not blood-stained were included in this study, with the first milliliter being discarded in all samples. RESULTS: In the routine amniocentesis group abnormal amniotic fluid optical density readings were significantly more frequent in fetuses with increased bowel echogenicity compared with those with nonechogenic bowel (8/40 [20%] vs 3/64 [5%], respectively; p < 0.001). In the hyperechogenic bowel group abnormal amniotic fluid optical density readings were found in four samples (29%). Overall, 12 of 54 fetuses (22%) with increased bowel echogenicity had a detectable peak at 410 nm. Three of the 12 (25%) fetuses with echogenic bowel and positive readings for hemoglobin were chromosomally abnormal. CONCLUSIONS: Fetal small bowel echogenicity is associated with the presence of heme pigments in amniotic fluid as determined by amniotic fluid optical density at 410 nm. Swallowing of amniotic fluid after intraamniotic bleeding seems implicated in the etiology of second-trimester echogenic bowel in both euploid and aneuploid fetuses. (A M J O BSTET G YNECOL 1996;174:839-42.)

Deviation in amniotic fluid optical density at a wavelength of 450 nm in Rh-immunized pregnancies from 14 to 40 weeks' gestation: A proposal for clinical management

Our purpose was to study deviations in values of amniotic fluid optical density at 450 nm in Rh-immunized pregnancies in the second and third trimesters and to propose a clinical management plan. A total of 789 amniotic fluid single and serial values of deviations in optical density at 450 nm were performed on Rh-immunized pregnancies from 14 to 40 weeks' gestation. The relationship of the deviations in amniotic fluid values of optical density at 450 nm to varying degrees of fetal disease were examined. In Rh-negative fetuses (unaffected) amniotic fluid values rise until 22 to 26 weeks before decreasing to term. In fetuses at risk of dying in utero, values are higher and trends rise. A clinical management plan was devised on the basis of the amniotic fluid findings of deviations in optical density at 450 nm. A clinical management scheme consisting of four zones is outlined. Rh-negative fetuses have minimal invasive procedures. Fetuses at risk of death undergo early cordocentesis for evaluation and therapy. Values that fall in between can be separated into two zones on the basis of the degree of risk.

Relationship between amniotic fluid optical density and L/S ratio.

Determination of the lecithin-sphingomyelin (L/S) ratio to predict fetal lung maturation requires rather complicated laboratory techniques which are not always available on a 24-hour basis in all hospitals. For that reason more simple tests have been developed. One of these tests, the determination of amniotic fluid optical density at 650 nm (OD 650), was initially reported to correlate well with the L/S ratio, but later studies gave varying and conflicting results. To assess the possible usefulness of measurement of amniotic fluid OD 650 we determined the correlation between L/S ratio and OD 650 in 90 amniotic fluid samples from 90 pregnant women. All samples were obtained by transabdominal amniocentesis between 26 and 39 weeks' gestation. Indications for amniocentesis were threatened premature labor (n = 49), fetal growth retardation (n = 25), and rhesus sensitization (n = 16). The OD 650 and the L/S ratio were determined in the same amniotic fluid sample using standard techniques. A statistically significant positive correlation was found between the OD 650 and the L/S ratio. Considering an OD 650 reading of 0.15 or greater and an L/S ratio of 2.0 or higher as indicative of fetal lung maturation, 25.5% of the OD 650 readings appeared to be false positive, and 28% were false negative as compared with the L/S ratio. It is concluded that the low predictive values of positive and negative optical density readings preclude the clinical application of this simple test.

Have Liley charts outlived their usefulness?

Fetal blood and amniotic fluid samples were obtained fetoscopically from 59 rhesus-isoimmunized pregnancies at 18 to 25 weeks' gestation. Fetal hemoglobin was measured and amniotic fluid optical density deviation at a wavelength of 450 nm determined. Two sets of normal reference values for optical density at 450 nm and fetal hemoglobin at 16 to 36 and 16 to 25 weeks were established from 475 amniotic fluid and 153 fetal blood samples obtained from pregnancies not complicated by fetal hemolysis. As expected, there was a significant linear correlation between the degree of fetal anemia and the amniotic fluid optical density at 450 nm in rhesus-isoimmunized pregnancies. However, the values of optical density at 450 nm were widely scattered, thereby limiting their ability to predict accurately the severity of disease in these second-trimester pregnancies. In 25 of the patients, the value of optical density at 450 nm was determined at 6 to 16 days before fetoscopy. The severity of fetal anemia could not be predicted by the trend in optical density at 450 nm. These data suggest that the only reliable method to determine the severity of rhesus isoimmunization in the second trimester of pregnancy is the direct measurement of fetal hemoglobin.

Sonographic measurements of the fetal spleen: clinical implications.

Normal values for fetal spleen dimensions are proposed, including longitudinal, coronal, and transverse diameters, the perimeter, and the estimated volume. Similar values were then obtained in cases of Rh-immunization and prolonged premature rupture of the membranes. A good correlation between amniotic fluid optical density and fetal spleen size was found. Only severely affected fetuses showed splenic values above the upper limit. Since sonographic examination can be regarded as a reliable method, nomograms can be useful in detecting growth disorders of the fetal spleen and thus provide a new complementary method to identify possible fetal diseases of genetic disorders.

Correlation of amniotic fluid optical density at 650 nm and lecithin/sphingomyelin ratios with phosphatidylglycerol

In this study we have attempted to correlate amniotic fluid optical density measurements and lecithin/sphingomyelin (L/S) ratios with the presence of phosphatidylglycerol. An 85% correlation (126 of 148) of all three parameters was noted. When the assumption was made that phosphatidylgylcerol is indicative of fetal pulmonary maturity, 93 of 94 fluid samples having an optical density at 650 nm ≥0.15 had demonstrable phosphatidylglycerol for a 1% false positive rate. In 53 fluid samples having an optical density at 650 nm <0.15, phosphatidylglycerol was present in 11 and absent in 42, a 21% false negative rate. The same analyses with lecithin/sphingomyelin ratios showed a 5% false positive rate and a 31% false negative rate.

Changes in the management of severely Rh-immunized patients

Since July 1, 1978, we have instituted the following changes in the management of severely Rh-immunized patients: (1) serial amniotic fluid optical density (ΔOD450) values and real-time ultrasound scanning beginning at 21 weeks' gestation, (2) fetal transfusion as early as the twenty-third week, (3) ultrasound surveillance during and after intrauterine transfusions, and (4) planned premature delivery with neonatal exchange transfusions for selected cases between 29 to 32 weeks and for all patients after 32 weeks' gestation. The perinatal survival rate (83.8%) in 37 isoimmunized pregnancies managed with this regimen was significantly higher (p < 0.05) than in 34 such pregnancies (55.9%) managed according to the protocol utilized during the previous four years.

Intra-uterine Transfusions to the Rhesus-Immunized Fetus in the Department of Obstetrics, National Hospital, Oslo 1968–1979. The Fetal Prognosis by Intra-uterine Transfusions in Relation to Amniotic Fluid Blood Pigment Index

During the years 1968-79, 115 intra-uterine transfusions (IUT) were performed in 71 severely Rhimmunized pregnant women at 26-32 weeks' gestational age. Thirty-five (approx. 50%) infants survived; 28 died in utero and 9 in the neonatal period. The selection of patients and technique is described. The amount of transfused blood in cord blood at birth is presented for the majority of liveborn infants.The study emphasizes that the outcome of IUT is entirely dependent on the degree of hemolysis at the time of the initial IUT. Among 30 patients with an amniotic fluid optical density difference at 450 mμ 0.6, respectively

Intra-uterine transfusions to the Rhesus-immunized fetus in the Department of Obstetrics, National Hospital, Oslo 1968-1979. The fetal prognosis by intra-uterine transfusions in relation to amniotic fluid blood pigment index.

During the years 1968-79, 115 intra-uterine transfusions (IUT) were performed in 71 severely Rh-immunized pregnant women at 26-32 weeks' gestational age. Thirty-five (approx. 50%) infants survived; 28 died in utero and 9 in the neonatal period. The selection of patients and technique is described. The amount of transfused blood in cord blood at birth is presented for the majority of liveborn infants. The study emphasizes that the outcome of IUT is entirely dependent on the degree of hemolysis at the time of the initial IUT. Among 30 patients with an amniotic fluid optical density difference at 450 m mu less than 0.3, a survival rate of 83% was registered compared with 36% and 0% in groups with values 0.3-0.6 and greater than 0.6, respectively.

Changes in amniotic fluid optical density at 450 mμ in Rh-sensitized patients after maternal hydrocortisone treatment

In anticipation of elective premature delivery (32 to 34 weeks of gestation), five Rh-sensitized pregnant women were given hydrocortisone succinate for enhancement of fetal lung maturation. Serial amniocenteses were performed and an abrupt drop in the optical density at 450 mμ (OD450) was observed in all cases immediately after administration of the steroid. Two infants in whom the OD450 remained low were followed safely to term. The others were delivered prematurely. All infants were Rh-sensitized and required one or more exchange transfusions, and all survived. It is tempting to speculate that glucocorticoids alter the antigen-antibody affinity and inhibit splenic macrophage sequestration, thus reducing erythrocyte destruction. Maternal steroid administration may prove to be therapeutic in the management of Rh-sensitization, but until its mechanisms are further delineated, extreme caution must be used in the interpretation of OD450 changes.

FACTORS AFFECTING FETAL SURVIVAL AFTER INTRAUTER TRANSFUSION FOR RHESUS ISOIMMUNIZATION

Intrauterine transfusion of the fetus is described in 165 pregnancies. The overall fetal survival rose from 28 per cent in 1964 to 1969 to 42-5 per cent in 1973 to 1975. Apart from technical complications of the procedure itself, the factors most likely to affect fetal survival were the gestational age and amniotic fluid optical density difference before the first intrauterine transfusion, the birth weight and the cord blood haemoglobin level.