In utero exchange transfusion by direct intravascular injection in severe erythroblastosis fetalis

Management of red blood cell alloimmunization in pregnancy

The main cause of fetal anemia is maternal red blood cell alloimmunization (AI). The search of maternal antibodies by indirect antiglobulin test allows screening for AI during pregnancy. In case of AI, fetal genotyping (for Rh-D, Rh-c, Rh-E and Kell), quantification (for anti-rhesus antibodies) and antibody titration, as well as ultrasound monitoring, are performed. This surveillance aims at screening for severe anemia before hydrops fetalis occurs. Management of severe anemia is based on intrauterine transfusion (IUT) or labor induction depending on gestational age. After intrauterine transfusion, follow-up will focus on detecting recurrence of anemia and detecting fetal brain injury. With IUT, survival of fetuses with alloimmunization is greater than 90% but 4.8% of children with at least one IUT have neurodevelopmental impairment.

In utero treatment of severe fetal anemia resulting from fetomaternal red blood cell incompatibility: a comparison of simple transfusion and exchange transfusion

OBJECTIVE

To compare in utero exchange transfusions (IUET) and in utero simple transfusions (IUST) for the treatment of fetal anemia resulting from red blood cell fetomaternal incompatibility.

STUDY DESIGN

Retrospective comparative study from January 2006 through December 2011. The two techniques were compared for effectiveness, complications, and neonatal outcomes.

RESULTS

36 patients had 87 IUETs and 85 patients 241 IUSTs. Gestational age at the first transfusion was similar in both groups (IUET: 27±3.8 weeks; IUST: 27±4.7 weeks; NS) as was the initial fetal hemoglobin level (IUET: 6.4±2.8g/dL; IUST: 6.0±2.5g/dL; NS). No significant differences were noted for postprocedure complications or efficacy. The daily drop in hemoglobin level was similar in both groups (IUET: 0.41±0.23g/dL/day; IUST: 0.44±0.17g/dL/day; NS) as were the time intervals between two procedures. Gestational age at birth was earlier in the IUET group (34.4±1.3 weeks vs 35.5±1.8 weeks; p<0.001), but the postnatal transfusions or exchange transfusions rates and the duration of intensive phototherapy did not differ. No significant differences were noted for the overall survival rates (IUET: 100%; IUST: 96.4%; p>0.99).

CONCLUSION

IUET does not appear to provide any benefits compared with IUST, neither to be associated with a higher complication rate. The choice of the technique depends on availability of packed blood cells with high hematocrit (70-80%).

Fetal surgery: principles, indications, and evidence

Since the first human fetal surgery was reported in 1965, several different fetal surgical procedures have been developed and perfected, resulting in significantly improved outcomes for many fetuses. The currently accepted list of fetal conditions for which antenatal surgery is considered include lower urinary tract obstruction, twin-twin transfusion syndrome, myelomeningocele, congenital diaphragmatic hernia, neck masses occluding the trachea, and tumors such as congenital cystic adenomatoid malformation or sacrococcygeal teratoma when associated with developing fetal hydrops. Until recently, it has been difficult to determine the true benefits of several fetal surgeries because outcomes were reported as uncontrolled case series. However, several prospective randomized trials have been attempted and others are ongoing, supporting a more evidence-based approach to antenatal intervention. Problems that have yet to be completely overcome include the inability to identify ideal fetal candidates for antenatal intervention, to determine the optimal timing of intervention, and to prevent preterm birth after fetal surgery. Confronting a fetal abnormality raises unique and complex issues for the family. For this reason, in addition to a maternal-fetal medicine specialist experienced in prenatal diagnosis, a pediatric surgeon, an experienced operating room team including a knowledgeable anesthesiologist, and a neonatologist, the family considering fetal surgery should have access to psychosocial support and a bioethicist.

An Audit of Outcome in Intravascular Transfusions Using the Intrahepatic Portion of the Fetal Umbilical Vein Compared to Cordocentesis

INTRODUCTION

Maternal red cell alloimmunization is a potential cause of perinatal morbidity and mortality. The outcome of severe disease has been transformed by the use of in-utero and particularly, fetal intravascular transfusion. In the majority of instances this is performed by cordocentesis. However, this cohort study represents the experience in a large tertiary referral centre in performing fetal intravascular transfusions via the intrahepatic vein (IHV).

METHODS

Over an 8-year period, 1997-2004, 221 in-utero transfusions (IUT) were performed for rhesus disease in 66 pregnancies. 86% had severe fetal anaemia caused by anti-D, 10.6% by anti-Kell and 3.4% by anti-c. The median maternal age of the cohort was 31 years (range 19-43). The median gestation at initial IUT was 25 weeks (interquartile range (IQR) 23-29 weeks).

RESULTS

A median number of three IUT were performed in each fetus (IQR 2-5) with a median haemoglobin at first fetal blood sampling of 7.3 g% (IQR 4.6-8.8 g%) (73% < or =5 SD and 27% < or =2 SD). Of the total intravascular transfusions, 170 were performed via the IHV (71.7%), 33 via cordocentesis (13.9%) and 1 by intracardiac puncture (0.5%). There were 'transient' bradycardias complicating 4.1% of all transfusions and amniorrhexis following 1.4%. 92% of babies were live born at a median gestation of 34 weeks (range 21-38) with a birth weight centile of 50 (range 3-90). There was no significant difference in intravascular transfusion complication rate when the procedure was performed via the IHV (7.6%) as compared to cord root puncture (3.0%) (Fisher's exact test, p < 0.47).

CONCLUSION

IUT performed by fetal IHV puncture is safe and carries no excess morbidity when performed for severe rhesus disease.

Treatment of fetal anemia due to red-cell alloimmunization with intrauterine transfusions in the Netherlands, 1988-1999

OBJECTIVE

To assess pregnancy outcome after intrauterine transfusion (IUT) for fetal anemia due to red-cell alloimmunization in the Netherlands over 11 years, in order to improve care and counseling.

METHODS

A retrospective cohort study was conducted from January 1, 1988, to January 1, 1999. Data were collected prospectively on all red-cell alloimmunized pregnancies requiring intrauterine blood transfusions. Primary outcome variables were fetal and neonatal survival in relation to the type of antibody, gestational age and presence or absence of hydrops. In addition, we studied short-term neonatal morbidity and procedure-related complications.

RESULTS

A total of 210 fetuses from 208 pregnancies received 593 transfusions. Overall survival rate was 86%. Survival of hydropic fetuses (78%) was significantly different from those without hydrops (92%). Low survival rates were especially found in hydropic fetuses with the first transfusion at gestational ages of 20 weeks or less (55%) or between 28 and 32 weeks (59%). In maternal rhesus D [Rh(D)] immunization 89% of fetuses survived, whereas survival in the case of Kell immunization was 58%. All fetuses with anemia due to Rh(c) immunization survived. The overall fatal procedure-related complication rate was 1.7% per procedure, resulting in a fetal loss rate of 4.8%.

CONCLUSIONS

Intrauterine intravascular transfusions are effective in the management of fetal alloimmune anemia. Fetal hydrops, mostly associated with late referral, decreases the chance of survival. To improve the outcome of red-cell alloimmunized pregnancies early diagnosis of fetal anemia and referral to a specialized center are important, enabling the start of treatment before hydrops develops.

The history of interventional ultrasound

Ultrasound has been used to guide interventional procedures for more than 30 years. Initial applications included biopsy techniques and simple aspiration of fluid collections. However, with improved sonographic imaging and the use of different ultrasonic probes as well as development of less invasive therapies, there has been an increase in the use of ultrasound to guide interventional procedures. Interventional ultrasound has become routine in most medical specialties. Because of the remarkable success of interventional procedures guided by sonography, combined with an outstanding safety record, there is no doubt that there will be a future increase in the number and types of interventional procedures performed under sonographic guidance.

RhD isoimmunization and current management modalities

OBJECTIVE

To review the literature on current perspectives and treatment of RhD isoimmunization.

DATA SOURCES

A search was conducted on MEDLINE and CINAHL, and supplemental articles/ bulletins were obtained from cited references and the Web site of the American College of Obstetricians and Gynecologists. Recent texts also were reviewed. Key search words: isoimmunization, Rho (d) immune globulin, fetal erythroblastosis, intrauterine blood transfusions, alloimmunization.

STUDY SELECTION

Articles and comprehensive works from indexed journals in the English language relevant to key words and published after 1995 were evaluated. Historically relevant periodicals and texts were also reviewed and selected.

DATA EXTRACTION

Data were extracted and organized under the following headings: testing of the antepartum patient, antepartum treatment of isoimmunization, testing of the postpartum patient, anti-D immune globulin, antepartum anti-D immune globulin prophylaxis, other antepartum and obstetric indications for anti-D immune globulin administration, postpartum anti-D immune globulin prophylaxis, nursing implications, and future possibilities.

DATA SYNTHESIS

RhD isoimmunized pregnancies continue to contribute to worldwide perinatal and neonatal morbidity and mortality. This review describes the basic knowledge necessary to care for these pregnancies and the current management modalities.

CONCLUSIONS

The management options for RhD compromised gestations continue to evolve almost as quickly as technological advances are made. Multiple areas of research in this field have surfaced, and nurses can become valuable members of these research teams. The literature also indicates that with the available knowledge and resources, the current rate of RhD isoimmunization can be further decreased with closer adherence to proposed management guidelines by all health care professionals.

The severity of immune fetal hydrops is predictive of fetal outcome after intrauterine treatment

OBJECTIVE

This study was undertaken to test the hypothesis that the degree of immune fetal hydrops predicts outcome in red blood cell-alloimmunized pregnancies.

STUDY DESIGN

In an 11-year period, 213 fetuses received 599 intrauterine transfusions. The outcome of 208 pregnancies, including two pairs of twins, was analyzed in a retrospective study. Eighty fetuses demonstrated ultrasonographic signs of hydrops at the start of treatment; 42 of these were classified as mildly hydropic and 38 were classified as severely hydropic. Reversal of hydrops as a result of treatment, survival, and neonatal morbidity was studied.

RESULTS

The overall survival rate of fetuses with hydrops was 78%. Of the fetuses with mild hydrops, 98% survived, whereas in cases of severe hydrops the survival rate was 55%. Intrauterine reversal of hydrops occurred in 65% of the fetuses with hydrops. The reversal rate was 88% in fetuses with mild hydrops and 39% in fetuses classified as severely hydropic. After reversal of hydrops, almost all of the fetuses survived (98%), whereas in cases of persistent hydrops outcome was unfavorable, with a survival rate of 39% for all fetuses and 26% for fetuses classified as severely hydropic.

CONCLUSION

In contrast with severe hydrops, there is a high rate of reversal of mild hydrops after adequate treatment. In our study 98% of fetuses survived after reversal of hydrops. To improve the outcome of red blood cell-alloimmunized pregnancies, early diagnosis of fetal anemia and referral to a specialized center are important; these steps enable the start of intrauterine treatment when hydrops is absent or still mild.

Diagnosis and treatment of fetal anemia due to isoimmunization

45 pregnant women affected by rhesus incompatibility were treated at the Department of Prenatal Diagnosis and Therapy, Vienna, between January 1992 and March 1993. 32 patients had a cordocentesis and on 21 fetuses, anemia requiring treatment was diagnosed. A total of 71 intravascular transfusions via the umbilical vein was given. The mean number of transfusions per fetus was 3.4 (range 1-11). Of the 7 fetuses who had already developed hydrops when therapy was started (hematocrit < 13%), 5 (71%) survived. The survival rate of non-hydropic anemic fetuses was 93% (13/14). By using intravascular transfusion for treatment of severe fetal anemia, a success rate of 86% (18/21) was achieved.

Ultrasound-guided fetal intravascular transfusions for severe erythroblastosis, 1984-1993

The results of the first 10 years' experience in ultrasound-guided fetal intravascular transfusions at the Royal Women's Hospital were reviewed. Since the first transfusion, a variety of techniques have been employed in 78 fetuses, all with severe erythroblastosis. A total of 288 intrauterine transfusions have been attempted with an overall survival rate of 75.6% (59 of 78). The overall survival rate for delivered fetuses improved from 64.3% (18 of 28) in 1984-1987, to 82.0% (41 of 50) in 1988-1993. There was a total of 33 hydropic fetuses, of whom 20 (60.6%) survived, significantly fewer compared with 86.7% (39 of 45) of the nonhydropic fetuses (odds ratio [OR] 0.25, 95% confidence interval [CI] 0.09 to 0.70, p < .01). Fetuses who were sicker at the time of transfusion, as reflected by larger haemoglobin deficits, had lower survival rates, as did those requiring transfusions at earlier gestational ages. When these variables were allowed for, the survival rate significantly improved over time (OR 6.3, 95% CI 1.3 to 30.4, p < 0.05), probably reflecting the increased skill of the ultrasonologists, but the presence of hydrops per se was no longer important. Variations of the technique employed, such as exchange or intraperitoneal transfusion, or different sites for transfusion, were not significantly related to survival.

Repeated direct fetal intravascular high-dose immunoglobulin therapy for the treatment of Rh hemolytic disease

Recently, administration of high-dose intravenous immunoglobulin (HDivIG) either to the mother or the neonate has been proposed in an effort to prevent progressive hemolysis in Rh(D) perinatal disease, but no cases have been published with direct fetal HDivIG administration. We report a case in which HDivIG was repeatedly administered by cordocentesis to a fetus affected by Rh(D) disease from 28 to 36 weeks gestation, at doses of approximately 450 mg/kg. The fetus required no transfusions, and the neonatal evolution was satisfactory. The treatment, performed at three weeks intervals, seemed to be useful in preventing fetal hemolysis. No fetal complications were present. Recurrent administration of HDivIG therapy to the fetus in cases of severe Rh(D) disease, appears to be feasible and free of serious complications to the fetus or the mother.

Intrauterine intravascular transfusion for fetal haemolytic anaemia: the Western Australian experience

OBJECTIVE

To report the first four years' clinical experience with fetal intravascular blood transfusion for the treatment of fetal haemolytic anaemia in Western Australia.

SETTING

King Edward Memorial Hospital, Perth, which is the sole tertiary level perinatal centre in Western Australia with a referral base of approximately 25,000 pregnancies each year.

METHODS

Transfusion was by injection of packed cells from Rh-negative donors into the fetal umbilical vein near the site of insertion into the placenta. Fetal haemoglobin levels were measured before and after each transfusion. In most cases, the fetus was paralysed by intramuscular tubocurarine.

RESULTS

Sixty intravenous transfusions were performed in 20 pregnancies. At the time of the initial transfusion, the mean haemoglobin level was 5.8 g/dL (range, 2.5-8.5 g/dL) and six fetuses had signs of hydrops. The case survival rate was 80% and the procedure survival rate was 93%. Three of the deaths occurred in the first five cases. Caesarean section was performed during two of the procedures, one because of bleeding from the cord puncture site and one because of tamponade of the umbilical vessels.

CONCLUSION

Fetal intravascular transfusion is a highly effective treatment for fetal alloimmunisation and allows pregnancies to continue to term and to be delivered vaginally. However, the procedure may be difficult and requires a team approach with ready access to fetal monitoring and emergency caesarean section. Our results suggest that increasing experience of the team is a major factor in improved outcome.

Management of fetal hemolytic disease by cordocentesis. I. Prediction of fetal anemia

Between January 1985 and November 1990, 128 pregnancies complicated by maternal red blood cell alloimmunization were referred to our Fetal Diagnosis and Treatment Unit. We examined the premise that an evaluation of fetal blood would accurately identify fetuses at risk of requiring antenatal transfusion therapy. Two hundred seventy-two diagnostic cordocenteses were performed. Criteria for the timing of repeat cordocenteses were developed retrospectively on the basis of the fetal hematocrit values, reticulocyte counts, and direct Coombs' test results of the first 84 pregnancies. These criteria were tested and confirmed prospectively on the next 44 pregnancies. On the basis of the first blood sample, four hematologic patterns (and their distributions) were identified in the 98 antigen-positive fetuses. Pattern 1: fetuses at low risk of having significant antenatal anemia (hematocrit less than 30%) (n = 11, 11%). These fetuses had normal hematocrit values and reticulocyte counts coupled with negative or trace-positive direct Coombs' test. No fetus in this group had significant antenatal anemia. Pattern 2: fetuses at intermediate risk of having anemia (n = 29, 31%). Pattern 2 fetuses had normal hematocrit values and either direct Coombs' titers of more than trace less than or equal to 2+ and normal reticulocyte counts or low reticulocyte counts (less than 2.5th percentile for gestation). Twenty-one percent (n = 6) of fetuses in pattern 2 had significant antenatal anemia. Patterns 3 and 4: fetuses at greatest risk of having severe anemia. These fetuses had normal hematocrit values associated with either reticulocyte counts greater than 97.5th percentile for gestation or a direct Coombs' test greater than or equal to 3+ (pattern 3, n = 49, 50%) or both, or a mild anemia (greater than 30% but less than 2.5th percentile for gestation) (pattern 4, n = 9, 10%). Eighty percent (n = 39) of fetuses with pattern 3 and 90% (n = 8) with pattern 4 developed a hematocrit value less than 30%. We conclude that evaluation of fetal hemolytic disease with a fetal blood specimen permits the identification of fetuses at high risk of having antenatal anemia.

Perinatal outcome following intravascular transfusion in severely isoimmunized fetuses

Twenty-six severely isoimmunized pregnancies managed exclusively with ultrasonographically guided intravascular fetal transfusions are reported. The mean gestational age plus and minus one standard deviation (+/- SD) was 26.3 +/- 3.6 weeks and the mean hematocrit (+/- SD) prior to initial transfusion was 20.6 +/- 6.7%. Four of seven hydropic fetuses and 9 of 19 without hydrops were less than or equal to 26 weeks gestation at the first transfusion. Overall survival was 85% (22/26). Survival was similar whether or not fetal hydrops was present (6/7 vs. 16/19) and whether or not the first transfusion was administered at less than or equal to 26 weeks gestation (10/13 vs. 12/13).

Placental transfer of cefazolin and piperacillin in pregnancies remote from term complicated by Rh isoimmunization

Although the administration of prophylactic antibodies for intrauterine transfusion is controversial, little information is available regarding placental transfer of antibiotics administered to the mother, or whether the presence of hydrops affects this placental transfer. Sixteen intravascular intrauterine transfusions were performed in 10 patients. Seven (10 procedures) patients were given 2 gm of cefazolin before the procedure and samples were obtained by fetal vascular access. Three patients (six procedures) were given 4 gm of piperacillin and samples were similarly obtained. Specimens were obtained for fetal serum, maternal serum, and amniotic fluid antibiotic concentration. The mean serum cefazolin concentration in hydropic fetuses was 18.04 +/- 3.37 micrograms/ml, and in nonhydropic fetuses the concentration was 21.02 +/- 17.8 micrograms/ml (p = 0.72). The mean fetal serum concentration of piperacillin was 22 +/- 12 micrograms/ml. The placental transfer of both drugs was similar. We conclude that the transplacental passage of these antibiotics is prompt and that the presence of hydrops does not significantly impair the passage of cefazolin.

New approaches in the treatment of haemolytic disease of the fetus

The incidence of Rh haemolytic disease of the fetus and newborn complicating pregnancy has fallen since the implementation of prophylaxis with Rh immune globulin. However, occasional mismatched blood transfusions and ineffective or inadequate prophylaxis still result in a few Rh-alloimmunized patients requiring treatment during pregnancy. The development of a safe technique for obtaining pure fetal blood samples has provided the opportunity to assess correctly the severity of anaemia and to study fetal haematology and biochemical parameters, and hence to gain a better understanding of the pathophysiology of this condition. The aim of antenatal management is to predict whether or not the fetus is severely affected, to correct fetal anaemia and to deliver the baby at the optimal time. Fetal IVT is the standard treatment in severe Rh alloimmunization in many centres. However, high volume transfusion without overloading the fetal circulation, as well as increasing the interval between transfusions without jeopardizing the fetal condition, can be achieved by a combination of IVT and IPT. Thus, the total number of transfusions needed and the overall procedure-related risk for each fetus is reduced. With the recent advances in fetal medicine, haematology and neonatology, the survival rate of affected fetuses in some centres is now about 90%. Fetal death will continue to be associated with two sets of circumstances: trauma or complications due to IVT or IPT in early gestation when delivery is not feasible, and late referrals with such severe hydrops that its reversal is not possible. There is still, therefore, a need for research into new methods of treatment, such as high dose intravenous IgG, which can non-invasively diminish fetal red cell destruction.

Percutaneous umbilical blood sampling

Percutaneous umbilical blood sampling (PUBS), also called cordocentesis, is a newly introduced technique that enables blood samples to be obtained from the fetus in utero for a variety of conditions. The major applications are for the diagnosis of fetal infections, karyotype analysis, fetal growth retardation, diagnosis of hematologic conditions, and metabolic evaluation. This procedure is gaining in popularity, since it provides direct information on fetal blood status. It can be applied to therapeutic manipulations such as in utero transfusions or drug administration. The procedure is remarkably safe and has few technical problems. The applicability of its use in the assessment of fetal thrombocytopenia is also discussed in detail.

The effect of intravascular transfusion on umbilical venous pressure in anemic fetuses with and without hydrops

Human fetal umbilical venous pressure was measured during 20 intravascular transfusions performed for treatment of hemolytic anemia. The mean (+/- 1 SEM) gestational age at the time of transfusion was 29.3 +/- 1 weeks and the mean beginning hematocrit was 27% +/- 2%. The mean volume of infused packed red blood cells (70% hematocrit) was 90.3 +/- 7 ml. The mean hematocrit at completion of the procedure was 48% +/- 1%. In nonhydropic fetuses umbilical venous pressure rose progressively from 6.7 +/- 1 mm Hg at the start of transfusion to 10.9 +/- 1 mm Hg at the completion of transfusion (p less than 0.002). However, most fetuses who began the infusion with a normal umbilical venous pressure ended the transfusion with a normal umbilical venous pressure (less than 10 mm Hg). Fetuses with immune hydrops (n = 2) had elevated umbilical venous pressure values before the initiation of transfusion therapy when compared with the first transfusion of nonhydropic fetuses (12.5 +/- 0.5 vs. 5.7 +/- 1 mm Hg, p = 0.01). However, the umbilical venous pressure measurements declined into the normal range within 24 hours of the first transfusion; this normalization was too rapid to be explained by the reversal of liver hypertrophy or portal hypertension. There was no demonstrable relationship between the rise in umbilical venous pressure and either the gestational age, the volume transfused, or the rise in hematocrit. This study demonstrated: (1) In terms of the umbilical venous pressure, direct intravenous infusion of the human anemic fetus is well tolerated; (2) the elevated umbilical venous pressure associated with immune hydrops can correct rapidly with red blood cell replacement.

Prediction of hematocrit decline after intravascular fetal transfusion

Fetal blood sampling and intravascular transfusion via cordocentesis allow more precise fetal evaluation and treatment in isoimmunized pregnancies. However, the timing of repeat transfusion has remained empiric. In this report we review our experience with fetal transfusions in isoimmunized pregnancies to evaluate the ability to predict fetal hematocrit decline and thereby determine the optimum timing for repeat transfusions. Between March 1986 and March 1988, 60 intravascular fetal transfusions were performed in 20 patients. Fetal transfusions were excluded from analysis if blood samples were unable to be obtained before and after transfusion, as well as at the beginning of the next transfusion or birth. Fifty-three procedures were analyzed. Two equations were used to predict the fetal hematocrit at the subsequent transfusion. The difference between observed and predicted hematocrits at the beginning of a subsequent transfusion or birth was -0.9% +/- 5.8% with equation 2, which was the more accurate formula in the majority of fetuses. Prediction of fetal hematocrit decline may be used to determine the optimum timing of repeat transfusion.

Intra-uterine exchange transfusion under ultrasound guidance

Thirty intra-uterine exchange transfusions (I.U.E.T.) under ultrasound guidance were performed on 15 pregnancies in 14 severely Rh-sensitized women. Our technique and a new method of catheterization of the umbilical cord are described. I.U.E.T. were commenced at 19-34 gestational weeks and repeated up to 5 times at 15 to 60 days intervals. The lowest pretransfusion fetal hemoglobin was 3 milligrams at 25 weeks. All the hydrops (4 cases) reversed a few days after the first procedure. The survival rate is 50% for hydropic fetuses and 66.6% for all cases. This technique avoids fetal hypervolemia and also too repetitive procedures by quick renewal of red cells. Catheterization offers a simple and safe access to the umbilical vein even with important fetal movements.

Hydrops revisited: literature review of 1,414 cases published in the 1980s

This paper reviews 47 series of hydrops fetalis (804 cases) and 610 individual cases published since 1980. From this large number of cases, guidelines are derived for prenatal diagnosis and management.

Two hundred intrauterine exchange transfusions in severe blood incompatibilities

Two hundred intrauterine exchange transfusions were performed under local anesthesia in 107 cases of blood incompatibilities (60 fetuses with severe anemia and 47 with hydrops). Under sonographic guidance, depending on fetal and placental position, an optimal puncturing site was selected along the umbilical vein: placental insertion, fetal insertion, or fetal intraabdominal segment. Tests were immediately performed to confirm fetal origin of blood obtained and estimate hemoglobin level. Blood used for exchange transfusion was compatible with maternal blood and had a hematocrit value of 75%. Exchange transfusion was continued until a hemoglobin level of 16 gm/dl was reached. This procedure was first associated with intraperitoneal transfusions and was subsequently used independently once a month to maintain an adequate hemoglobin level. In 4 fetuses with hydrops, antenatal regression of this sign was observed in 33 cases (70.2%). Overall outcome of 107 fetuses after exchanges was 84 living neonates (78.5%), 15 deaths in utero, and eight neonatal deaths. The survival rate was 91.6% for fetuses without hydrops and 61.7% for those with hydrops. The advantage of exchange transfusion appears to be rapid and efficient correction of anemia with elimination of incompatible fetal red blood cells.

Fetal cardiac output in the isoimmunized pregnancy: a pulsed Doppler-echocardiographic study of patients undergoing intravascular intrauterine transfusion

The mechanism of development of hydrops fetalis in severe isoimmunization has been subject to speculation. We performed pulsed Doppler assessment of cardiac output in 13 severely isoimmunized fetuses before and after intravascular transfusion and compared the results with 37 control fetuses between 20 and 34 weeks' gestation. The cardiac index of the anemic fetuses was significantly greater than that of the control group. A significant (right ventricle, p less than 0.01; left ventricle, p less than 0.02) increase in indexed output was noted from both ventricles and in the combined ventricular output (mean +/- SEM 644 +/- 35.3 ml/kg/min in control fetuses versus 879 +/- 86.0 ml/kg/min in anemic fetuses, p less than 0.006). An increase in cardiac output was also noted when anemic fetuses were compared with gestational age-specific norms. We conclude that severely anemic fetuses of isoimmunized pregnancies tend to have significantly higher cardiac output than do unaffected fetuses and that this high output state may play a part in the development of hydrops fetalis.

Pulsed Doppler flow-velocity waveforms in the prediction of fetal hematocrit of the severely isoimmunized pregnancy

We previously reported a significant relationship between the hematocrit levels of anemic fetuses and information derived from ultrasonographic and Doppler flow-velocity waveforms. In this study we prospectively tested two formulas for the prediction of hematocrit values, by use of gestational age, presence or absence of hydrops, and Doppler indices. Although one of the two formulas predicted hematocrit values significantly, the only component of the formula that made a significant contribution was fetal hydrops. We conclude that currently available fetal Doppler measurements are unable to be applied in the prospective prediction of hematocrit values in anemic fetuses of isoimmunized pregnancies.

Prenatal diagnosis of platelet disorders

The antenatal diagnosis of platelet disorders represents real progress in the early detection of haemorrhagic diseases occurring in the fetus. However, the diagnosis is only possible in some cases during the first trimester of gestation, and not in the first weeks as is the case for other hereditary disorders such as abnormal haemoglobins. This delay can be reduced now that the molecular abnormalities responsible for some platelet disorders have been discovered. If the region of chromosome 17 and the DNA sequence coding for the glycoproteins GP IIb-IIIa were known, this would make possible the recognition of the gene defect responsible for Glanzmann's thrombasthenia. This could also permit the diagnosis of Glanzmann's thrombasthenia at the gene level, i.e. during the first weeks of gestation. However, the use of gene markers could be limited by the fact that a monomorphic clinical expression of Glanzmann's thrombasthenia could correspond to different genetic mutations which can all result in a defect in GP IIb-IIIa synthesis and assembly. If such diagnosis could be made very early, it would only represent real progress if a specific treatment could be applied. New therapeutic approaches to immune thrombocytopenia during pregnancy appear to be possible and can be applied when there is a risk to the fetus, they are still either experimental or anecdotal and there is a real need for a well-designed clinical trial. In all fetal platelet disorders, the risk of fetal death following fetal blood sampling must not be underestimated and very careful, intensive care is necessary after such an investigation. In the absence of a specific therapy, this antenatal diagnosis must be restricted to cases in which the risk of severe haemorrhagic complications are anticipated and where there is a well-documented family history. The patients must be properly informed of all the aspects of the investigation, including the possible risks. As has been the case for other haematological disorders, progress will be made, and we can anticipate that eventually in utero bone-marrow transplantation or gene correction be performed to cure the disease before birth.

Pathophysiology of pressure changes during intrauterine transfusion

Intraperitoneal and umbilical vein pressure readings were obtained during intrauterine transfusion in patients with Rh alloimmunization. In 15 nonacidotic fetuses, mean umbilical vein pressure before transfusion (4.5 mm Hg, SD = 2.3) increased by 4.6 mm Hg (delta umbilical vein pressure confidence intervals +2.8 to +6.4; p less than 0.0001) with transfusion. delta Umbilical vein pressure correlated positively with the increase in hematocrit level (r = 0.55; p less than 0.05) and negatively with gestational age (r = -0.58; p less than 0.05). Basal umbilical vein pressure was raised in the only acidotic fetus, whereas delta umbilical vein pressure was 0. Intraperitoneal pressure was recorded in 11 fetuses before and after transfusion, five of which were associated with fetal heart rate changes or preexisting ascites. Basal intraperitoneal pressure (2.5 mm Hg, confidence intervals 1.4 to 3.6) was significantly lower than basal umbilical vein pressure (confidence intervals, 3.2 to 5.8; p less than 0.02). In uncomplicated intraperitoneal transfusions, intraperitoneal pressure rose significantly (delta intraperitoneal pressure = +5.8; confidence intervals 2.9 to 8.8; p less than 0.005). In four transfusions associated with fetal bradycardia or tachycardia, delta intraperitoneal pressure (range, 16 to 26) was greater than in uncomplicated transfusions (range, 1 to 9). delta Intraperitoneal pressure was 0 in the fetus with ascites. These results implicate increases in umbilical vein pressure and intraperitoneal pressure in immediate complications of intrauterine transfusion, and support a role for intraperitoneal pressure monitoring during intraperitoneal transfusion.

Intravascular exchange and bolus transfusion in the severely isoimmunized fetus

Eight Rh-sensitized fetuses, between 21 weeks 2 days and 35 weeks of gestation, received 31 intravascular transfusions (13 exchange and 18 bolus) and one intraperitoneal transfusion under ultrasonographic guidance. The interval between transfusions was 13.4 +/- 4.7 days. Posttransfusion hematocrit dropped at a rate of 1.0% +/- 0.6% per day. Procedure time for the bolus transfusion was shorter than for the exchange transfusion (t test, p less than 0.001). Bleeding from the puncture site complicated 10 of the 31 intravascular transfusions, without apparent maternal or fetal consequences. Fetuses were delivered between 33 and 36 weeks of gestation, after lung maturity was achieved.

Prenatal diagnosis using sonographic guided cordocentesis

Cordocentesis has been practiced as a diagnostical tool for prenatal diagnosis of intrauterine infections, hematological disorders, metabolic status of the fetus and rapid cytogenetic analysis. The performance of 198 cordocentesis is presented over 3 years of experience. A 21 gauge spinal needle is inserted via the optimal point on the maternal abdomen under real-time ultrasonic guidance into the insertion of the umbilical cord in the placenta. Successful cordocentesis were achieved in 98.5% of the cases. Termination of pregnancy was directly related to the procedure in only 1%. Hematoma surrounding the puncturing site was demonstrated in one case, but without damage to the fetus. In our series the main indication for performing cordocentesis was the need for rapid karyotyping. The use of fetal lymphocytes for chromosomal analysis offers a rapid and a reliable method for routine clinical demands. The availability of a rapid chromosomal analysis offers a considerable advantage in pregnancies of advanced gestational age. In those pregnancies it appears to be most important to have a rapid diagnosis where anatomical structural anomalies are associated with chromosomal malformations in up to 30%. The metabolic status of the fetus is considered in either acute distress or in cases of suspected sub-optimal metabolic hemostasis, where IUGR or oligohydramnios are demonstrated. Cordocentesis, even though is a new technique, turns to play a major role in modern perinatology. The possibility of a direct rout to fetal blood vessels early during the pregnancy bears the tremendous potential of early diagnosis and treatment.

Prediction of fetoplacental blood volume in isoimmunized pregnancy

Direct intravascular fetal transfusion under ultrasound guidance allows precise evaluation of both fetal anemia and adequacy of therapy. In addition, the change in hematocrit after transfusion may be used to estimate the circulatory fetoplacental blood volume. In this study we present the estimates of fetoplacental blood volume calculated at the time of intravascular fetal transfusions. Between March 1986 and March 1988, 60 intravascular fetal transfusions were performed in 20 patients. The 56 procedures in which fetal hematocrits were obtained both before and after transfusion were analyzed. The mean fetoplacental blood volume before transfusion was 94.0 ml/kg. Furthermore, the fetoplacental blood volume per kilogram fetal weight decreased with advancing gestation. These estimates of fetoplacental blood volume and changes relative to gestational age may be useful in the treatment of the severely isoimmunized fetus. Reliance on the more recently generated fetoplacental blood volumes may allow more accurate predictions of transfusion volumes and estimation of the hematocrit after transfusion.

Diagnostic fetal umbilical blood sampling in the management of isoimmunization

Current management of isoimmunization in pregnancy is predicted on the assumption that all sensitized women carry antigen-positive fetuses. In addition, management is based on indirect predictors of the magnitude of the fetal hemolytic disease. We present a preliminary report using a new approach of direct fetal blood sampling for the diagnosis and treatment of these patients. This form of evaluation provides specific information about fetal red blood cell antigen status and the degree of fetal anemia at an earlier gestational age than that validated by the Liley curves and eliminates empiricism from both the diagnosis and treatment of the isoimmunized pregnancy. The use of such a management protocol reduces the need for multiple invasive procedures in fetuses at little risk for disease and provides specific information about the status of those fetuses truly at risk.

Management of isoimmunized pregnancy by use of intravascular techniques

Twenty-two patients who had 23 pregnancies complicated by isoimmunization were managed by the use of intravascular methods on an outpatient basis. Nine patients underwent 30 percutaneous fetal blood sampling procedures to determine fetal blood type or hematocrit, without complication. Thirteen patients underwent 45 intrauterine fetal transfusions via the umbilical vessels and 16 intraperitoneal fetal transfusions. The overall survival rate in this series was 85.7%. Survival among fetuses that were hydropic at initial evaluation was 83.3%. The procedure-related perinatal mortality rate for intravascular intrauterine transfusions was 2.2%. Knowledge of fetal blood type and hematocrit allowed treatment individualized to the specific needs of each patient. In particular, the ability to transfuse blood directly into the vascular system of the hydropic fetus proved to be lifesaving in those patients.

Changes in fetal acid base status during intravascular transfusion

Umbilical venous pH, PCO2, PO2, and base excess was measured immediately before and after 72 intravascular transfusions in 34 fetuses with erythroblastosis fetalis. In 67 uncomplicated transfusions, infused adult blood led to a mean (95% confidence intervals) fall in pH (0.037, CI 0.029 to 0.044) and base excess (2.03, CI 1.61 to 2.45) and a mean rise in PCO2 (0.24 kPa, CI 0.13 to 0.35). These changes correlated significantly with the increase in fetal haemoglobin and packed cell volume. Five transfusions were associated with complications within six hours: intrauterine death in two, fetal-distress necessitating delivery in two, and preterm labour in one. Two had pre-existing acidosis, whereas two of the three with normal blood gas and acid base measurements before transfusion had acute changes that were outside the normal ranges that had been established in uncomplicated transfusions.

The reversal of hydrops fetalis by intravascular intrauterine transfusion in severe isoimmune fetal anemia

Seventy-two intrauterine intravascular transfusions were performed on 26 patients with severe erythroblastosis fetalis. Twenty of the 26 fetuses were hydropic at the time of referral. Of the 20 hydropic fetuses, 16 (80%) survived. Hydrops was completely reversed in 13 of the 16 fetuses (81%). Total protein of less than 3 gm/dl, albumin less than 2 gm/dl, and a hematocrit level of less than 15% were associated with hydrops fetalis. After hydrops was reversed, total protein greater than 3 gm/dl, albumin greater than 2 gm/dl, along with a sustained hematocrit level of greater than 15%, were found. Only three neonates were born with minimal ascites, two of whom had had intraperitoneal transfusions before intravascular treatments. There were 21 survivors of the total group, giving an overall survival rate of 82%. There was one neonatal death from severe respiratory distress syndrome. Thirty-eight percent of the neonates did not require exchange transfusions in the newborn period. Intrauterine intravascular transfusions appear to be an effective mode of therapy in severe erythroblastosis fetalis and not only increase survival rates but also decrease neonatal morbidity and mortality.

Pulsed Doppler flow-velocity waveforms before and after intrauterine intravascular transfusion for severe erythroblastosis fetalis

Pulsed Doppler studies of the fetal and maternal circulations were carried out before and after 64 intrauterine transfusions performed on 24 fetuses. A model was derived for the prediction of hematocrit before the first transfusion: Hematocrit = 7.778 - (0.088 x peak velocity in descending aorta) + (0.968 x gestational age [weeks]) - (10.911 if hydrops present) (r = 0.876, p less than 0.0001). An alternative formula, excluding hydrops, was slightly less predictive: Hematocrit = 45.312 - (56.261 x umbilical cord Pourcelot index) - (0.128 x peak velocity in descending aorta) + (1.042 x gestational age) r = 0.822, p less than 0.001). Neither model was accurate in the prediction of hematocrit before second or subsequent transfusions. A third model was derived from second-transfusion data: Hematocrit = 40.524 - (0.045 x peak velocity in descending aorta) - (10.693 x pulsatility index of maternal uterine artery) (r = 0.81, p less than 0.003). However, this model was unable to predict hematocrit before third or later transfusions. No changes in Doppler parameters before and after transfusion were found. We conclude that pulsed Doppler ultrasound may be helpful in the evaluation of isoimmunized pregnancies, in differentiating anemic from normal fetuses. It does not appear to be useful in determining the timing of later transfusions. The lack of change before and after transfusions suggests that these vessels will not provide significant information concerning the effect of rapid volume and hematocrit changes in the fetus.

Fetal intracardiac transfusions in patients with severe rhesus isoimmunisation

Six patients with pregnancies of 19-31 weeks' duration showing evidence of erythroblastosis fetalis were treated with 25 fetal intracardiac blood transfusions. Complications related to the procedure occurred on five occasions in three patients. In two of the six patients the fetus died, but it was unlikely that death was related to the intracardiac transfusions. Fetal intracardiac blood transfusion may result in potentially severe complications but offers an alternative when transfusion cannot be performed into the umbilical cord.

Introduction of a programme for intravascular transfusions at severe rhesus isoimmunization

Thirty-seven fetuses with severe rhesus isoimmunization with a gestational age of less than 30 week underwent 92 intravascular transfusions. Of these, 77 were intracardiac, 13 umbilical vein and two umbilical artery transfusions. Procedure related complications occurred at eight (10%) intracardiac and at two (14%) umbilical cord transfusions. Reversal of hydrops was observed in 10 of 16 fetuses. The perinatal mortality among transfusion treated fetuses was 8/37 (21%). It is concluded that intravascular, intrauterine transfusion leads to improved results among fetuses with early onset of hydrops. Problems concerning indications and technique are discussed.