Rh-sensitized Pregnancies Research Articles

Discordant Middle Cerebral Artery Peak Systolic Velocity Doppler Studies in a Fetus With RhD Alloimmunization

Doppler measurement of the fetal middle cerebral artery peak systolic velocity is a valuable tool in detecting the presence of fetal anemia in Rh-sensitized pregnancies. We present a case in which discordant left and right middle cerebral artery Dopplers complicated clinical management. An RhD-alloimmunized patient had middle cerebral artery Dopplers at 30 weeks of gestation, which showed an elevated peak systolic velocity in the left middle cerebral artery, greater than 1.55 multiples of the mean, but the right middle cerebral artery was within the normal range. The amniotic fluid change in optical density at a wavelength of 450 nm was consistent with the right middle cerebral artery Doppler. When both Dopplers were greater than or equal to 1.5 multiples of the mean, fetal blood sampling revealed a hematocrit of 28%. Postnatal cranial ultrasound examination showed normal architecture, but there was persistent discordant Dopplers in the left versus the right middle cerebral artery. Measurement of both left and right middle cerebral artery peak systolic velocities may identify patients with intrinsic variations in cranial blood vessels resulting in abnormal Doppler flows.

AMNIOTIC FLUID (AF) ARGINIE-VASOPRESSIN (AVP) CONCENTRATIONS IN NORMAL PREGNANCIES AND INTRAUTERINE GROWTH RETARDATION (IOGR)

AVP is released by the fetus but only in response to osmotic, but also to nonosmotic stimuli such as hypoxia. Once released, AVP is excreted via fetal urine into AF where it has a long half life compared to plasma (ca 8 hours). Tbe hypothesis of the present study therefore was, that fetal hypoxia might be diagnosed by elevated AF-AVP levels. As a model we used IUGR fetuses which are known to he hypoxic. 25 infants entered the study because IUGR was suspected by ultrasound. The normal AF-AVP levls as control values were determined in 93 uncomplicated pregnancies where amniocentesis was performed for other reasons (L/S ratio determinations, genetic reasons, rh-sensitized pregnancies with rh-negative fetuses). HPL values were measured by RIA as were Af-AVP values. Results: The mean AF-AVP levels in normal pregnancies from 16 to 41 weeks of gestation was 2.37 ± 1.16 SD pg/ml. There was no significant difference with different gestational age. At birth 7 of the 25 infants hod normal birth weight and 18 actually had IUGR. There was a significant correlation between the degree of IUGR and AF-AVP levels (r=.59, p<0.05). The correlation between the HPL values and the degree of IUGR was the same as for AF-AVP values (r=.59, p<0.05). Discussion: 1) To our knowledge we report AF-AVP values for the greatest group of normal pregnancies yet published. 2) AF-AVP levels are elevated in IUGR. Ihe levels dependent on the severity of IUGR. These data support the usefulness of AF-AVP determinations for the diagnosis of fetal wellbeing as demonstrated in a previous study in rh-erythroblastosis (1). The elevated AF-AVP levels in IUCR might explain findings of diminished urine production of these fetuses (2). (1)Stegner et al. Acta Endocrinol 112,267,1986 (2)Wallenburg et al. J Perinot Med 6,233,1977

Improved Care for Rh-Isoimmunized Patients in Saudi Arabia

ABSTRACT Although the number of patients with Rh isoimmunization in pregnancy has been decreasing in recent years, this category of patients contributes significantly to the perinatal mortality in ...

Conservative management of a severely Rh-sensitized pregnancy

A case of severe rhesus isoimmunization managed without intrauterine fetal transfusions is presented.

Fetal transfusion.

In the Rh-sensitized pregnancy, direct treatment of the fetus has been practiced for over two decades. Although Rh immune prophylaxis has markedly decreased the incidence of Rh sensitization, there are still fetal deaths due to this disease. Current management of the severe form of Rh disease includes serial transabdominal intrauterine transfusions, preterm delivery and intensive neonatal care. Heart failure in the fetus may be treated by administering medications to the mother. Ascites or pericardial effusion are easy to detect with ultrasound imaging. Digoxin and diuretics have been used to reverse the ultrasound evidence of fetal congestive heart failure. Recently, direct fetal intravascular transfusion by fetoscopy has proven effective. In some instances, hydrops fetalis appears to be reversed by such transfusions. The use of promethazine and plasmapheresis have only limited success in ameliorating the disease in the fetus.

The Antenatal Management of the Rh Sensitized Woman

The antenatal management of the Rh-sensitized woman is aimed at delivery of a living child with an optimum chance of survival. The author describes the improved methods of management that have dramatically reduced associated perinatal wastage and then goes on to describe the continuing search for new, more effective, and less invasive means of treating the Rh-sensitized pregnancy.

Promethazine for Rh-sensitized pregnancies : Charles A, Blumenthal L. Promethazine hydrochloride therapy in severely Rh-sensitized pregnancies. Obstet Gynecol 60:627, 1982

Promethazine for Rh-sensitized pregnancies : Charles A, Blumenthal L. Promethazine hydrochloride therapy in severely Rh-sensitized pregnancies. Obstet Gynecol 60:627, 1982

Dilation of the fetal umbilical vein in rhesus hemolytic anemia: A predictor of severe disease

Presented in part at the annual meeting of the American Institute of Ultrasound in Medicine, September, 1980, New Orleans, Louisiana. Reprint requests: Greggory R. DeVore, M.D., Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Southern California, LAClUSC Women’s Hospital, 1240 North Mission Road, Los Angeles, California 90033. fourth week of gestation, the bone marrow begins to produce hematopoietic cells, and the liver and spleen concomitantly decrease their production.’ When Rh antibody-mediated hemolytic anemia develops, however, the fetal liver increases its erythropoietic activity and enlarges. This is associated with decreased synthesis of serum albumin, with resultant low osmotic pressure.z When this is severe, fluid accumulates in the extravascular compartments, and fetal hydrops results. Although the delta optical density (AOD) of amniotic fluid bilirubin at 450 rnp is used to discover those fetuses with severe hemolytic disease in whom intrauterine transfusion (IUT) is mandatory, serial diagnostic ultrasound is a useful adjuvant in the evaluation of fetal well-being. Presented here are the results of a study designed to evaluate, by means of ultrasound, fetal hepatic congestion resulting from increased erythropoiesis in Rh-sensitized pregnancies. The fetal umbilical vein diameter (UVD) in the-amniotic fluid (AF) and the liver (L) were measured from images obtained with a contact B and a realtime linear array scanner (Fig. 1). In a cross-sectional evaluation of 94 normal control fetuses, the UVD in the AF progressively increased from week 18 through week 30 of ges-

Renin activity and concentrations of angiotensin I and II in amniotic fluid of normal and RH-sensitized pregnancies

Renin activity and the concentrations of angiotensin I and angiotensin II in amniotic fluid of second- and third-trimester pregnancies were determined by radioimmunoassay. Between the 28th and 38th wk of gestation, the mean renin activity in the amniotic fluid was higher than during early pregnancy (before the 18th wk of gestation). Both renin activity and the concentrations of angiotensin I and II were increased in some cases of Rh-incompatibility. One to two weeks after the administration of betamethasone to the mother with threatened premature delivery, the intra-amniotic renin-angiotensin system was slightly suppressed. In urine samples of newborns, angiotensin concentrations were in the same range as those found in the amniotic fluid; renin activity was very low or undetectable in the urine of male neonates (1–7 days of age). Thus, angiotensin II in the amniotic fluid may be derived both from fetal urine and/or as the product of enzymatic reactions in the amniotic sac; the latter is dependent not only on the presence of renin and converting enzyme but also on the local renin substrate (angiotensinogen) concentration.

Ovenstone Factor in the Management of Rh Sensitization

Several methods have been developed for analyzing amniotic fluid to aid in the management of rhesus isoimmunization. Because all methods attempt to predict the severity of fetal hemolysis based on the original findings of Bevis and on the amount of unconjugated bilirubin in amniotic fluid as measured by its optical density at 450 millimicron, they share two possible sources of error: calculation of exact gestational age and accurately reading bloody or contaminated amniotic fluid. The Ovenstone Factor measures the derivative of the bilirubin curve against wavelength and thereby avoids some of the contaminating pigments at 450 millimicron. This paper compares the predictive accuracy of two methods, Liley versus Ovenstone Factor, in 78 samples of fluid from 46 patients. Predictions were correct in 80% of infants using Ovenstone Factor and 67% using the Liley curve, and incorrect in only 7% and 13%, respectively. The Ovenstone Factor, with its simplicity and high predictive accuracy, is an excellent additional tool in the management of Rh-sensitized pregnancies.

Amniotic fluid analysis in Rh-sensitized pregnancies

This paper delineates the results of analysis of 234 Rh-sensitized pregnancies. It is now possible to predict the outcome in an Rh-isoimmunized pregnancy based only on the mean amniotic fluid, Δ450¯. This is an improvement over past methods since it does not depend upon calculation of weeks of pregnancy.

Amniotic fluid creatinine in the Rh-sensitized pregnancy

Amniotic fluid creatinine concentrations were analyzed in 165 samples from 62 normal and 32 Rh (D)-sensitized pregnancies. A close correlation between maturity and amniotic fluid creatinine was observed in the uncomplicated pregnancies, a concentration of less than 1.8 mg. per cent being predictive of fetal immaturity. In contrast, amniotic fluid creatinine was significantly lower in the sensitized pregnancies, values less than 1.8 mg. per cent commonly (11 of 15) accompanying fetal maturity. In addition, a paradoxical decline in concentration with advancing gestation was shown to be associated with serious perinatal morbidity and a 40 per cent risk of perinatal death. These data suggest that serial analysis of creatinine concentrations in conjunction with routine analysis of amniotic fluid bilirubin4 and total osmolality5 may be of significant value in the prospective clinical management of the Rh-sensitized pregnancy.

The first Rh-isoimmunized pregnancy

There is adequate information in the literature from which to conclude that the greatest opportunity for fetal salvage is the first Rh-sensitized pregnancy. Too many interpret this to mean that the first affected baby will be minimally or mildy involved. This report of 109 first affected pregnancies indicates that 20 per cent of the Rh-positive fetuses are severely involved, that as many as 10 per cent may require intrauterine transfusion, and that the perinatal mortality rate is 10 per cent. These data are presented to emphasize the necessity of careful antepartum assessment of the fetus during the first isoimmunized pregnancy.

Amino acid variations in amniotic fluid and maternal plasma from Rh-sensitized pregnancies: Part II

Amino acids were quantitated by ion-exchange chromatography in amniotic fluid and maternal plasma from Rh-sensitized pregnancies. Twenty-four patients of 34 to 40 weeks' gestation were studied, and results were compared to those in normal pregnancy. Significant differences were found for amino acid concentrations in amniotic fluid and maternal plasma from those patients in whom fetal death occurred. When the fetus survived, amino acid levels were similar to normal levels. In particular, it was noted that proline levels were markedly elevated in the amniotic fluid of patients in whom fetal death occurred (p < 0.001). From this preliminary work arises the interesting possibility that an increased amniotic fluid versus maternal plasma proline level may be of diagnostic assistance in severe Rh disease.

Computer-assisted Spectrophotometric Analysis of Amniotic Fluid in Erythroblastosis Fetalis

A computer program has been used to assist in the analysis of absorbance changes in amniotic fluid from Rh-sensitized pregnancies. The advantages of the program are reduced chance of human error in calculation or communication, numerical reports in a form similar to those of other chemistry values on the patient's chart, and increased laboratory efficiency. Programmed calculation should be combined with a visual inspection of a wavelength scan for detection of interfering pigments.

Amniotic fluid proteins in normal and Rh-sensitized pregnancies

Amniotic fluid proteins (481) were determined for 221 normal and Rh-sensitized pregnancies. The normal range and mean values are shown for various stages of gestation. Determination of normal values for amniotic fluid proteins during early gestation are important as a unit of reference in the prenatal diagnosis of genetically related defects. In general, the larger the birth weight of the normal infant, the lower the amniotic fluid protein value prior to delivery. In normal pregnancies the values decrease with increasing gestation. In pregnancies with mild and moderate erythroblastosis fetalis the values are essentially the same. With severe disease, the protein range is greater and the trend not always downward with increasing gestation. With hydrops fetalis, the values rise and a value of 0.800 Gm. per 100 ml. with an elevated bilirubin level is diagnostic of hydrops fetalis.

Assessment of Rh disease by ratios of bilirubin to albumin and hemopexin to albumin in amniotic fluid.

Abstract We examined 105 amniotic-fluid samples from 36 Rh-sensitized pregnancies for concentration of bilirubin, protein, albumin and hemopexin (heme-binding beta glycoprotein). Bilirubin measurements obtained spectrophotometrically (Liley method) were compared with levels of total protein, albumin, hemopexin and chemically determined bilirubin. Ratios of the concentrations of chemically assessed bilirubin to albumin reflected most accurately the degree of fetal hemolysis and fetal outcome. A ratio above 0.10 was recorded in eight of 10 patients receiving intrauterine transfusions and in two requiring multiple exchange transfusions. A ratio below 0.05 indicated patients needing no or one transfusion. A rising ratio of hemopexin to albumin in 10 cases usually suggested no or mild involvement; leveling (six cases) and falling ratios (15 cases) were found when exchange or intrauterine transfusions were needed. Inconclusive or negative Liley values were observed in four cases, but ratios of bilirubin and hem...

Rh-D antibody titer in amniotic fluids: Its use as an index of the severity of erythroblastosis fetalis

A study was made of Rh antibody titers in the amniotic fluids from 42 Rh-sensitized pregnancies. It was learned that the antibody titer of such fluid can be used as a reliable index of the severity of kemolytic disease in the fetus.

Amniotic fluid lactic dehydrogenase in Rh-sensitized pregnancy

Electrophoretic determination of the enzyme lactic dehydrogenase was performed from the amniotic fluid of 36 patients. Twelve patients had normal gestations while 8 patients had some degree of intrapartum fetal distress. The remaining 16 patients were Rh negative, 10 of whom were sensitized. The lactic dehydrogenase values in the cases of fetal distress were not significantly different from those observed in normal gestations. An increase in Fraction V of lactic dehydrogenase was constant in situations of Rh isoimmunization with severe fetal involvement.

An improved, rapid procedure for the determination of amniotic fluid bilirubin and its use in the prediction of the course of Rh-sensitized pregnancies

A simple, rapid chloroform extraction method for analyzing amniotic fluid samples in Rh sensitization is presented. It consists of the extraction of the unconjugated bilirubin into chloroform and the determination of the bilirubin concentration in the CHCl 3 layer. The values show excellent correlation with those obtained by the method of Liley for estimating the 450 mμ peak. No interference occurs in samples containing excessive heme pigments, meconium, and turbidity. The retrospective evaluation of 137 pregnancies from which 276 amniotic fluid specimens were analyzed with the chloroform extraction technique is presented. The patients are grouped according to clinical severity of the disease in the infant at birth. A prediction graph has been constructed which can be used to aid in the management of individual Rh-sensitized pregnancies. The importance of serial amniotic fluid samples is emphasized.