Cordocentesis: an appraisal of risks

Fetal and neonatal alloimmune thrombocytopenia: progress and ongoing debates

Fetal and neonatal alloimmune thrombocytopenia (AIT) is a result of a parental incompatibility of platelet-specific antigens and the transplacental passage of maternal alloantibodies against the platelet antigen shared by the father and the fetus. It occurs in approximately 1 in 1000 live births and is the most common cause of severe thrombocytopenia in fetuses and term neonates. As screening programs are not routinely performed, most affected fetuses are identified after birth when neonatal thrombocytopenia is recognized. In severe cases, the affected fetus is identified as a result of suffering from an in utero intracranial hemorrhage. Once diagnosed, AIT must be treated antenatally as the disease can be more severe in subsequent pregnancies. While there have been many advances regarding the diagnosis and treatment of AIT, it is still difficult to predict the severity of disease and which therapy will be effective.

Outcome of fetal cardiac defects

PURPOSE OF REVIEW

The present review summarizes the prenatal and postnatal outcome of cardiac anomalies and sustained arrhythmias diagnosed during fetal life.

RECENT FINDINGS

The outcome of sustained fetal arrhythmias has improved with greater experience using Sotalol for atrial flutter, and digoxin and amiodarone for 1: 1 reciprocating tachycardia. The outcome of fetal conduction system disease secondary to maternal Sjögren's antibodies has noticeably improved with transplacental dexamethasone. The postnatal prognosis for atrioventricular block associated with left atrial isomerism, however, remains very bleak. Assessing the effect of prenatal diagnosis on the outcome of structural defects remains difficult because of the high number of extracardiac anomalies and chromosome defects in this group. Preoperative survival is improved, but postoperative mortality has not improved. One clear advantage of prenatal diagnosis is the selection of fetuses that may benefit from in-utero intervention to limit the progression of their disease or lessen its severity at birth.

SUMMARY

For the most part, postoperative mortality of structural cardiac defects is not significantly improved by prenatal diagnosis. In-utero management of tachyarrhythmias and conduction system disease has improved postnatal outcome, except for the fetus with atrioventricular block and left atrial isomerism.

Fetal Intravascular Transfusion for Hydropic Disease due to Rhesus Isoimmunization

OBJECTIVE

To evaluate the management of hydropic fetuses, due to rhesus isoimmunization, with fetal intrauterine intravascular transfusions.

MATERIAL AND METHODS

This is a retrospective analysis of 18 rhesus-negative pregnant women presenting at our hospital with fetal hydrops during a 7-year period. All cases were managed with serial intrauterine intravascular transfusions with the goal of delivery by cesarean section beyond 33 weeks of gestation. All patients received prophylactic ampicillin and ritodrine for 4 days after the procedure.

RESULTS

There were 11 mildly and 7 severely hydropic fetuses. All fetuses with mild hydrops and 5 of the 7 with severe hydrops were delivered alive after 32 weeks of gestation in a good condition. Two fetuses both with severe hydrops died in utero, at 28 weeks of gestation. Intrauterine reversal of hydrops occurred in 90.9% of fetuses with mild hydrops and in 57.1% of severely hydropic fetuses.

CONCLUSIONS

The survival rate for the hydropic fetuses in our study was 88.9% and it was associated with the severity of fetal hydrops.

Fetal blood sampling in twin pregnancies

OBJECTIVE

To evaluate the role of fetal blood sampling for prenatal diagnosis in twin pregnancies.

METHODS

This was a retrospective study of 84 twin pregnancies that had undergone fetal blood sampling between the years 1977 and 2000. These results were compared with those from a similar study on amniocentesis and chorionic villus sampling.

RESULTS

Miscarriage occurred in 3.6% of cases after fetal blood sampling. The total fetal loss rate was 13.6% and the fetal loss that could be attributed to the procedure was 8.2%. The procedure-related fetal loss rate was dependent on the indication for fetal blood sampling. The rates of preterm delivery at </= 32 weeks, preterm delivery at </= 35 weeks, perinatal mortality at </= 28 weeks, perinatal mortality at > 28 weeks and neonatal mortality were 16.9%, 28.3%, 10.9%, 3.1% and 7.7%, respectively.

CONCLUSION

Fetal blood sampling in twin pregnancies carries higher risks for the fetus than do amniocentesis and chorionic villus sampling. However, it remains useful in evaluating the fetal condition in special circumstances such as hydrops and infection.

Is Rh immune globulin needed in early first-trimester abortion? A review

The prophylactic use of Rh immune globulin has been a medical success, protecting women who could be at risk from exposure to the Rh(D) antigen. Thus, it is not surprising that Rh(D) immunoprophylaxis has been extended from women with term pregnancies to all women with miscarriages, abortions, and ectopic pregnancies. In this article we review the existing medical literature to assess the risks of fetomaternal hemorrhage and Rh isoimmunization after complications of a first-trimester pregnancy, induced abortion, or ectopic pregnancy. The evidence to support the use of Rh immune globulin in the first trimester is sparse, but there is theoretic evidence of its necessity. Despite weak evidence to support its use, there is little risk.

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.

Complications of diagnostic ultrasound-guided percutaneous umbilical blood sampling: analysis of a series of 341 cases and review of the literature

OBJECTIVE

To study the complications of percutaneous umbilical blood sampling (PUBS) conducted for purely diagnostic purposes, in a retrospective study of 341 personal cases and an analysis of 4922 cases from literature.

SUBJECT

Analysis of the sampling procedure and complications seen in 341 punctures, including 12 failures.

INTERVENTIONS

Freehand echo-guided percutaneous umbilical blood sampling. PARAMETERS STUDIED: Conditions in which the blood samples were taken (gestational age, indications, placental location, technique--including number of punctures, duration); total number of fetal deaths and number of fetal deaths related to the procedure; other complications (bradycardia, hematoma of the umbilical cord, hemorrhage, premature births).

RESULTS

20 fetal deaths (FDs) were recorded in 341 cases (5.87%) (figures for the literature: 189/4922 = 3.84%); 3 FDs appeared to be directly related to the procedure (0.88) (figures for the literature: 48/4922 = 0.98%). There were 32 cases of bradycardia (9.38%); this complication was seen more frequently after repeated and prolonged punctures. Hematomas of the cord (1.47%) were seen when punctures were attempted in a free loop of the cord. There was a marked increase in the number of complications (8.96% FDs and 20.73% of bradycardias) when the procedure lasted more than 10 min and/or when more than 3 punctures were attempted (33.33% FDs). These two occurrences are closely related to the gestational age at which the PUBS was conducted, the placental location, the experience of the operators and the condition for which the sample was being taken. Pathological pregnancies (fetal malformation, disease or hypotrophy of the fetus, diseases of the amniotic fluid) had a mortality rate of 11.24% (19/169), whereas fetuses that were presumed to be healthy had a lower risk of 0.58% (1/172).

CONCLUSIONS

The overall mortality (including all fetal and neonatal deaths) appears to be around 5.0% (between 3.84 and 5.87%), but the mortality rate directly related to the procedure seems to be around 1% (between 0.88 and 0.98%). It seems that the fetal mortality rate is closely related to: (a) The state of the fetus and thus to the indication of the procedure. The higher overall mortality rate observed is related to the natural history of the conditions for which the procedure was conducted and the time taken to conduct the procedure and the number of punctures. This depends on the experience of the teams, on the observation of the rule that the attempt should not be prolonged beyond 10 min and no more than 2 punctures should be attempted in any one session.

Transplacental transfer of cefuroxime in uncomplicated pregnancies and those complicated by hydrops or changes in amniotic fluid volume

The transplacental transfer of cefuroxime was determined at antenatal fetal blood sampling in a cross sectional study of 78 patients between 15-35 weeks' gestation, 8-138 minutes after a maternal intravenous dose of 750 mg. Mean serum cefuroxime concentration, measured by high performance liquid chromatography, was 7.4 (95% confidence interval (CI) 6.8 to 8.1) mg/l in control fetuses; concentrations in hydropic fetuses were similar (6.2 mg/l, CI 4.7 to 7.7) but in fetuses with oligohydramnios they were significantly lower, (4.9 mg/l, CI 3.6 to 6.2). Antibiotic concentration did not correlate with gestational age and remained unchanged by transfusion of packed red cells. We conclude that (i) fetal serum concentrations of cefuroxime obtained after a maternal dose of 750 mg are only adequate for prophylaxis against organisms with a minimum inhibitory concentration of < 4 mg/l and (ii) transplacental passage of cefuroxime is significantly reduced in the presence of oligohydramnios.

Alloimmune conditions and pregnancy

Transfer of fetal red blood cells and platelets to the maternal circulation can stimulate an immune response with production of immunoglobulin that can cross the placenta. Similarly, passage of maternal stem cells to an immunologically incompetent fetus can theoretically produce graft-versus-host disease. disease. Maternal sensitization to red blood cell antigens such as D and Kell can result in anaemia, hydrops, and death in an incompatible fetus. Current assessment of these pregnancies involves serial analysis of amniotic fluid bilirubin concentration, with umbilical cord blood sampling reserved for special circumstances; neither ultrasound or Doppler blood flow analysis are accurate in the prediction of fetal haematocrit. Intravascular transfusion is the treatment of choice for hydropic fetuses. Perinatal survival in non-hydropic fetuses is similar with either intravascular or intraperitoneal transfusion, and the choice of procedures is individualized. Isoimmune fetal thrombocytopenia is usually the result of maternal sensitization to the PlA1 antigen. There is significant risk of intracranial haemorrhage, both antepartum and during labour and delivery. Umbilical cord blood sampling at term can determine fetal platelet count and the need for platelet transfusion, and can aid in deciding the appropriate route of delivery.

Necrotizing enterocolitis following intrauterine blood transfusion

Intravascular intrauterine transfusion allows a more sophisticated and exact approach to the management of severe Rh hemolytic disease. This technique involves direct manipulation of the fetal umbilical vessels; its hazards include umbilical cord trauma and thrombosis or emboli. The consequences of such events in utero are largely unknown. In this case necrotizing enterocolitis occurred in a full-term infant after three intrauterine intravascular transfusions.

High-dose intravenous IgG for the treatment of severe rhesus alloimmunization

The value of intravenous immunoglobulin (IVIG) in the treatment of 24 severely Rh-sensitized pregnant women was studied. IVIG was infused at a daily dose of 0.4 g/kg maternal body weight for 4-5 consecutive days, and was administered again 15-21 days later until delivery, depending on the evolution of the hemolytic disease. Our population was divided into 3 groups according to the time of onset of therapy: group 1 (n = 8), before 20 weeks' gestation; group 2 (n = 7), 20-28 weeks, and group 3 (n = 9), after 28 weeks. Initial mean anti-D level was significantly higher in group 1 (25.9 +/- 12.9 IU/ml) than in the other 2 groups, whose mean values were, however, higher than 10 IU/ml. Amniotic-fluid total bilirubin levels before the onset of therapy were pathologic, and in 55% of the cases they coincided with zone 3 of Liley's chart. Hydrops fetalis at the onset of treatment accounted for the only 3 fetal deaths in groups 1 and 2. None of the fetuses developed hydrops during treatment. Six of the 9 neonates in group 3 were depressed at birth (1-min Apgar below 7). However, at 5 min only 1 newborn showed an Apgar below 7. Mean birth weight was over 2,500 g in all the cases. Neonatal hematological condition in group 2 (50% of the babies required only phototherapy) was better than in the other 2 groups (transfusional therapy). There was a significant fall in maternal anti-D titers and intrauterine hemolysis after IVIG treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for cordocentesis and fetal intravascular transfusion

There is little information on the impact of technical aspects or patient characteristics on the risks of accessing the fetal circulation. We performed 594 diagnostic cordocenteses and 156 intravascular transfusions over 6 years. Pancuronium was administered during 52% of procedures. The number of needle punctures per successful procedure was unrelated to the placental location. However, the number of punctures required was lower if the placental cord origin rather than a midsegment was targeted (p less than 0.0001). Bleeding from either the uterine or umbilical cord puncture site was not believed to be clinically significant, although the duration of bleeding was greater after arterial puncture than after venous puncture (p = 0.01) and after intravascular transfusion than after diagnostic cordocentesis (p less than 0.0001). Amnionitis (suspected plus verified) complicated 0.5% of procedures. Preterm premature rupture of membranes (with or without amnionitis) followed 0.4% of procedures. Fetal bradycardia occurred in 6.6% (6.6 +/- 0.8 minutes; range, 0.1 to 35 minutes). There were five perinatal losses after a diagnostic procedure, yielding an uncorrected loss rate of 0.8% (5/594). Each was associated with a prolonged bradycardia; each fetus was ultimately demonstrated to have been unsalvageable. Two independent risk factors for bradycardia were identified--arterial puncture and severe, early onset intrauterine growth retardation. The administration of pancuronium reduced the incidence of bradycardia in appropriately grown fetuses (6% to 1.5%; p less than 0.05), but did not alter the incidence in growth-retarded fetuses. We conclude that cordocentesis performed with a needle guide is a safe procedure but that its risk varies with both the indication and the vessel punctured.

Fetal blood sampling and pregnancy loss in relation to indication

OBJECTIVE

To assess the relation between the indication for fetal blood sampling and pregnancy loss following the procedure.

DESIGN

Retrospective study.

SETTING

The tertiary referral Fetal Medicine Units at Guy's and University College Hospitals, London.

SUBJECTS

Women undergoing diagnostic fetal blood sampling in four groups: (1) 94 having prenatal diagnosis with normal ultrasound findings; (2) 94 with a structural fetal abnormality; (3) 30 having fetal assessment and (4) 35 with non-immune hydrops.

INTERVENTIONS

Freehand ultrasound guided fetal blood sampling from umbilical cord, intrahepatic vein or fetal heart.

MAIN OUTCOME MEASURES

Pregnancy losses were divided into those within 2 weeks and those 2 weeks after the procedure, obstetric accidents and neonatal deaths.

RESULTS

The 253 patients had fetal blood sampled on 268 occasions. Fifty-one pregnancies were terminated. Overall, 51 of the remaining 202 desired continuing pregnancies were lost, of which 19 (9%) were lost within 2 weeks of the procedure. After exclusion of the pregnancies that were terminated, the procedure-related losses within 2 weeks of sampling were 1 in 76 (1%), 5 in 76 (7%), 4 in 29 (14%) and 9 in 36 (25%) in groups 1, 2, 3 and 4 respectively.

CONCLUSIONS

The risk of fetal blood sampling is increased in abnormal pregnancies, reflecting the underlying pathology and this must be taken into account when counselling patients before the procedure.

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.

Umbilical cord haematoma as a complication of intrauterine intravascular blood transfusion

Between October 1985 and February 1989, 49 ultrasound-guided intravascular fetal blood transfusions were performed in 16 patients (14 with rhesus (Rh) isoimmunization, 2 with non-immunologic hydrops fetalis (NIHF)). As an intra-operative complication, perivascular haematoma of the cord occurred in three patients (7 per cent). In two cases, fetal bradycardia necessitated delivery by Caesarean section at 30 and 32 weeks' gestation, respectively. In the third case, fetal bradycardia developed during transfusion, at 31 weeks' gestation, but normalized within 3 min. The baby was delivered as planned at 36 weeks of gestation, after another transfusion at 34 weeks. Dislodgement of the needle tip into perivascular tissue, caused by sudden fetal or maternal movements, is the reason for this complication. The haematoma develops as a result of delayed recognition and continuous transfusion into Wharton's jelly. Cord haematoma may be diagnosed in time by continuous ultrasound imaging, as illustrated in case 3. To minimize the risk of needle dislodgement during transfusion, sedation of the mother and complete immobilization of the fetus by injecting a short-acting muscle relaxant into the umbilical vessel are recommended.