Induced Abortion and the Risk of Rh Sensitization

Importance

While population-level data suggest Rh immunoglobulin is unnecessary before 12 weeks' gestation, clinical evidence is limited. Thus, guidelines vary, creating confusion surrounding risks and benefits of Rh testing and treatment. As abortion care in traditional clinical settings becomes harder to access, many people are choosing to self-manage and need to know if ancillary blood type testing is necessary.

Objective

To determine how frequently maternal exposure to fetal red blood cells (fRBCs) exceeds the most conservative published threshold for Rh sensitization in induced first-trimester abortion.

Design, Setting, and Participants

Multicenter, observational, prospective cohort study using high-throughput flow cytometry to detect circulating fRBCs in paired maternal blood samples before and after induced first-trimester abortion (medication or procedural). Individuals undergoing induced first-trimester abortion before 12 weeks 0 days' gestation were included. Paired blood samples were available from 506 participants who underwent either medical (n = 319 [63.0%]) or procedural (n = 187 [37.0%]) abortion.

Exposure

Induced first-trimester abortion.

Main Outcomes and Measures

The primary outcome was the proportion of participants with fRBC counts above the sensitization threshold (125 fRBCs/5 million total RBCs) after induced first-trimester abortion.

Results

Among the 506 participants, the mean (SD) age was 27.4 (5.5) years, 313 (61.9%) were Black, and 123 (24.3%) were White. Three of the 506 participants had elevated fRBC counts at baseline; 1 of these patients had an elevated fRBC count following the abortion (0.2% [95% CI, 0%-0.93%]). No other participants had elevated fRBC counts above the sensitization threshold after induced first-trimester abortion. The median change from baseline was 0 fRBCs, with upper 95th and 99th percentiles of 24 and 35.6 fRBCs, respectively. Although there was a strong association between the preabortion and postabortion fRBC counts, no other baseline characteristic was significantly associated with postabortion fRBC count.

Conclusions and Relevance

Induced first-trimester abortion is not a risk factor for Rh sensitization, indicating that Rh testing and treatment are unnecessary before 12 weeks' gestation. This evidence may be used to inform international guidelines for Rh immunoglobulin administration following first-trimester induced abortion.

Qualitative analysis of Doppler assessment used for surveillance of alloimmunized individuals

OBJECTIVES

To summarize image quality variables for alloimmunized women at risk for fetal anemia. To investigate the association between image quality with the highest and median middle cerebral artery peak systolic velocity (MCA-PSV) at the last visit and fetal anemia based on hemoglobin.

STUDY DESIGN

This study was a qualitative retrospective analysis of 192 Doppler ultrasound images used in the detection of fetal anemia in 26 alloimmunized women seen in a Minneapolis hospital over the past 3 years. Images were graded on seven criteria found in literature.

RESULTS

Of the images analyzed, 23 (12.0%) of the 192 met all seven image quality criteria. Using the highest MCA-PSV value, the sensitivity, and specificity were 55.6% and 94.1%, respectively. Using the median MCA-PSV value, the sensitivity, and specificity were 44.4% and 94.1%, respectively.

CONCLUSIONS

Only a minority of Doppler images meet all suggested image criteria. This could negatively impact the accuracy of the MCA-PSV measurements as indicated by the decreased sensitivity in our evaluations.

[Severe neonatal thrombocytopenia due to maternal alloimmunization: case report and literature review]

Prior to 1970, maternal alloimmunization was the leading cause of perinatal death. Currently, it has become rarer thanks to screening and monitoring in high-risk pregnancies. The advent of transcranial doppler has been a turning point in the monitoring of these pregnancies, as it is a reliable, non-invasive method for the diagnosis of fetal anemia. This helps clinicians decide whether or not to perform intrauterine transfusion. Anti-D immunoprophylaxis has also played an important role in preventing fetal and neonatal hemolytic anemia and its administration is currently well codified. Adequate management helps to avoid the effects of alloimmunization on the fetus and newborn as well as to reduce the risks of alloimmunization in subsequent pregnancies. We here report a case of severe fetomaternal rhesus (Rh) alloimmunization during unmonitored pregnancy complicated by fetoplacental anasarca.

Sensitivity of fetal RHD screening for safe guidance of targeted anti-D immunoglobulin prophylaxis: prospective cohort study of a nationwide programme in the Netherlands

OBJECTIVE

 To determine the accuracy of non-invasive fetal testing for the RHD gene in week 27 of pregnancy as part of an antenatal screening programme to restrict anti-D immunoglobulin use to women carrying a child positive for RHD DESIGN:  Prospectively monitoring of fetal RHD testing accuracy compared with serological cord blood typing on introduction of the test. Fetal RHD testing was performed with a duplex real time quantitative polymerase chain reaction, with cell-free fetal DNA isolated from 1 mL of maternal plasma The study period was between 4 July 2011 and 7 October 2012. The proportion of women participating in screening was determined.

SETTING

 Nationwide screening programme, the Netherlands. Tests are performed in a centralised setting.

PARTICIPANTS

 25 789 RhD negative pregnant women.

MAIN OUTCOME MEASURES

 Sensitivity, specificity, false negative rate, and false positive rate of fetal RHD testing compared with serological cord blood typing; proportion of technical failures; and compliance to the screening programme.

RESULTS

 A fetal RHD test result and serological cord blood result were available for 25 789 pregnancies. Sensitivity for detection of fetal RHD was 99.94% (95% confidence interval 99.89% to 99.97%) and specificity was 97.74% (97.43% to 98.02%). Nine false negative results for fetal RHD testing were registered (0.03%, 95% confidence interval 0.01% to 0.06%). In two cases these were due to technical failures. False positive fetal RHD testing results were registered for 225 samples (0.87%, 0.76% to 0.99%). Weak RhD expression was shown in 22 of these cases, justifying anti-D immunoglobulin use. The negative and positive predictive values were 99.91% (95% confidence interval 99.82% to 99.95%) and 98.60% (98.40% to 98.77%), respectively. More than 98% of the women participated in the screening programme.

CONCLUSIONS

 Fetal RHD testing in week 27 of pregnancy as part of a national antenatal screening programme is highly reliable and can be used to target both antenatal and postnatal anti-D immunoglobulin use.

Non-invasive prenatal diagnosis of fetal RhD by using free fetal DNA

OBJECTIVE

Anti-D immunoglobulin is applied to all pregnant women having RhD incompatibility to prevent hemolytic disease of the newborn. The aim of this study is to determine fetal RhD status in the Rh incompatible pregnancies with an non-invasive technique; free fetal DNA isolation from maternal circulation. In the case of Rh incompatibility especially with a history of previous fetal anemia, it can be beneficial to know Rh status antenatally in terms of monitoring fetuses with Rh positive [RhD(+)] status consciously.

MATERIALS AND METHODS

Total free DNA was isolated in 50 Rh negative [RhD(-)] pregnant women, who had RhD alloimmunisation with their husbands. The gene in isolated DNA was investigated with TagMan prob and real time PCR by using primers belonging to exon 7 of the RhD gene.

RESULTS

The authors analyzed 50 RhD(-) women by using quantitative real time PCR technique. Five of them were RhD(-) and the rest of them were found to be RhD(+). After birth one of the infants who were analyzed as RhD(+) were found to be RhD(-).

CONCLUSION

The detection of fetal RhD status by using a non-invasive method from maternal circulation was found to be possible. Assessing fetal RhD status non-invasively by using free fetal DNA in maternal blood will be cost-efficient, avoiding unnecessary indirect Coombs test and unnecessary Rhogam applications that is used in RH incompatible pregnancies. This study will throw a fresh light on prenatal diagnosis.

[Foetal Rhesus-D typing added to antenatal screening for infectious diseases and erythrocyte immunisation]

OBJECTIVE

Investigation of the accuracy and national implementation of foetal Rhesus-D typing (fRhD), introduced in 2011 for RhD-negative pregnant women.

DESIGN

Descriptive, national study.

METHOD

Results of fRhD in pregnant women in the first year after implementation were compared to results from cord blood RhD typing of the child.

RESULTS

0.05% of the fRhD results was false negative (9/18.383; 95% CI: 0.02-0.09), and 0.85% was false positive (157/18.383; 95% CI: 0.73-1.00). fRhD was incorrectly omitted in fewer than 1% of pregnant women. In 96.1% of the pregnant women, antenatal administration of anti-D prophylaxis was recorded. Recording of postnatal anti-D administration turned out to be lower (92%), but locally recorded data showed that postnatal anti-D was omitted in fewer than 2% of cases.

CONCLUSION

The percentage of false negative fRhD was statistically significantly lower (p < 0.05) than the critical limit of 0.25% determined beforehand by the Programme Committee of the Dutch Antenatal Screening Programme for Infectious Diseases and Erythrocyte Immunisation. The percentage of false positive fRhD was considered acceptable, and implementation of fRhD was more or less complete. Routine RhD-typing on cord blood was therefore omitted from January 2013. Antenatal and postnatal anti-D administration is now specifically indicated for RhD-negative pregnant women when fRhD is positive, thus saving about 10,000 unnecessary antenatal anti-D administrations per year. RhD-typing on cord blood is now performed only if the RhD blood type of the child of a RhD-negative mother is unknown at delivery, if a positive fRhD was found for multiple births, and in exceptional situations, e.g. if fRhD typing is not possible due to a rare genetic variation.

[Continuous medical evaluation of the prevention of fetomaternal rhesus-D allo-immunization]

OBJECTIVES

To evaluate the prevention of fetomaternal rhesus-D allo-immunization between 2008 and 2010. This evaluation was a part of the continuous medical evaluation (CME) that is compulsory in French hospitals. It was carried out using the tools recommended by the Haute Autorité de santé. We followed the national guidelines for the prevention of fetomaternal rhesus-D allo-immunization as outlined in 2005 by the national French college of Obstetrics and Gynecology.

MATERIALS AND METHODS

We audited 3926 consultations in the first four months of 2008. Based on the results of the audit, actions were implemented to improve care. In 2009, we audited 4021 consultations to look for improvement, and another 3932 consultations in 2010.

RESULTS

In 2008, 14% of the patients had an overall optimal prevention. After actions were taken, 44% of patients in 2009 and 58% of patients in 2010 demonstrated optimal prevention (P<0,05). Especially, the prevention of fetomaternal allo-immunization has been explained for 43% of the patients in 2008 and to 90% of them in 2010. And immunoprophylaxia has been prescribed to 70% of the patients in 2008 and to 93% of them in 2010.

CONCLUSION

This CME has resulted in a statistically significant improvement of the prevention of allo-immunization.

[Erythrocyte alloimmunization in pregnant women, clinical importance and laboratory diagnostics]

OBJECTIVE

The aim of this review is to give comprehensive summary of erythrocyte alloimunization of pregnant women, laboratory dignostics and clinical importance.

DESIGN

Review.

SETTING

University Hospital Olomouc, Transfusion Department, Department of Obstetrics and Gynecology.

SUBJECT AND METHOD

Based on literature analysis using database search engines PubMed, Google Scholar, Ovid in field of erythrocyte antibodies, laboratory diagnostics and clinical importance up-to-date knowledge.

CONCLUSION

Erythrocyte alloimunization anti-D antibodies decreases in connection with the introduction of immunoprofylaxis. Immunization of non RhD antibodies with impossibility using of immunoprofylaxis remains still clinical problem.

Development of a transparent interactive decision interrogator to facilitate the decision-making process in health care

BACKGROUND

Decisions about the use of new technologies in health care are often based on complex economic models. Decision makers frequently make informal judgments about evidence, uncertainty, and the assumptions that underpin these models.

OBJECTIVES

Transparent interactive decision interrogator (TIDI) facilitates more formal critique of decision models by decision makers such as members of appraisal committees of the National Institute for Health and Clinical Excellence in the UK. By allowing them to run advanced statistical models under different scenarios in real time, TIDI can make the decision process more efficient and transparent, while avoiding limitations on pre-prepared analysis.

METHODS

TIDI, programmed in Visual Basic for applications within Excel, provides an interface for controlling all components of a decision model developed in the appropriate software (e.g., meta-analysis in WinBUGS and the decision model in R) by linking software packages using RExcel and R2WinBUGS. TIDI's graphical controls allow the user to modify assumptions and to run the decision model, and results are returned to an Excel spreadsheet. A tool displaying tornado plots helps to evaluate the influence of individual parameters on the model outcomes, and an interactive meta-analysis module allows the user to select any combination of available studies, explore the impact of bias adjustment, and view results using forest plots. We demonstrate TIDI using an example of a decision model in antenatal care.

CONCLUSION

Use of TIDI during the NICE appraisal of tumor necrosis factor-alpha inhibitors (in psoriatic arthritis) successfully demonstrated its ability to facilitate critiques of the decision models by decision makers.

[Possibility to identify fetomaternal haemorrhage]

Fetomaternal haemorrhage (FMH) is a status characterised by penetration of fetal blood into the maternal circulation which happens mostly at delivery. FMH may cause erythrocytal alloimmunisation of woman. That is why anti-D immunoglobulin (IgG anti-D) is being administered to RhD negative women after delivery of RhD positive fetus. IgG anti-D is administered to RhD negative women standardly and in much greater quantities than is actually necessary. However, on the other hand, it is not possible to diagnose cases where a greater dose is required. To optimalise prevention of RhD alloimmunization in RhD negative women, it is important to diagnose conditions where fetomaternal haemorrhage (FMH) occurs, precisely define its volume and consequently administer the required dose of IgG anti-D. The ability to reliably detect fetomaternal haemorrhage (FMH) and precisely define its volume would allow better and less expensive prevention of RhD alloimmunization in RhD negative women. IgG anti-D could thus be administered only in cases that are actually indicated and only in doses necessary for preventing RhD alloimmunization. Accurate quantification of FMH is determined by flow cytometry.

DESIGN

Review.

SETTING

Department of Obstetrics and Gynecology, Department of Alergology and Clinical Immunology, University Hospital Olomouc.

Laboratory methods for Rh immunoprophylaxis: a review

The recommended dose of Rh immune globulin for postpartum Rh immunoprophylaxis is based on an estimation of the volume of the fetomaternal hemorrhage, if any, measured as the percent of fetal RBCs in a sample of the D– mother's blood. Laboratory methods for distinguishing fetal from maternal RBCs have been based on their different blood types (D+ versus D–) or predominant hemoglobin content (hemoglobin F versus hemoglobin A). We conducted a review of the medical literature describing laboratory methods for detecting and quantifying fetal RBCs in maternal blood samples. We also used data collected for the College of American Pathologists Fetal RBC Detection Surveys to determine which laboratory methods are used currently in hospitals in the United States. The rosette screen is used widely for identifying D– mothers who may require additional doses of Rh immune globulin for postpartum immunoprophylaxis. As the rosette screen targets the D antigen, it is not suitable for detecting a fetomaternal hemorrhage in D+ mothers or when the D type of the fetus or newborn is D– or unknown. The acid-elution (Kleihauer- Betke) assay is a sensitive laboratory method for quantifying a fetomaternal hemorrhage, but it is tedious, often inaccurate, and difficult to reproduce. Flow cytometry, using anti-D or anti-hemoglobin F reagents, offers a more precise quantification of fetal RBCs in maternal blood. However, flow cytometry services for this function are available in relatively few hospital laboratories in the United States because of logistic and fiscal impediments.

[The importance of laboratory diagnosis in allo-immunization through pregnancy and hemolytic disease of the newborn]

BHNN is an affection in which life duration of fetus red cells is decreased by means of maternal antibodies opposing certain antigens inherited from the father.The present study will prove the importance of laboratory tests in the diagnosis of alloimmunization through pregnancy and BHNN.

MATERIAL AND METHOD

Laboratory determinations were performed between March 2008 and February 2009 on samples from 187 Rh negative pregnant female with incompatible pregnancy and Rh D positive newborns; there was used a certain algorithm for and identifying.

RESULTS

After applying the proposed algorithm, 4.2% of the cases were discovered to be immunized, whereas 2.6% of the cases were BHNN. As the specificity of irregular antibodies involved, 62.5% were anti D, 25% anti Kell and 12.5% anti E. The results show the fact that the incidence of these pathological entities is far more extended than in other countries.

CONCLUSIONS

Owing to the fact that alloimmunization by pregnancy and BHNN is still a frequent phenomenon, an attentive supervision is very important both for preparing the patient and the medical team aiming to prevent perinatal morbidity.

[Noninvasive prenatal diagnosis from maternal plasma in serological conflicts in Poland: current practice and future prospects]

The principles and results of noninvasive prenatal diagnosis in serological conflicts in Poland were described in the following work. Noninvasive fetal genotyping from plasma of immunized mother identifies women carrying fetus without incompatible antigen and risk of hemolytic disease. The presence of fetal RHD gene or RHCE*c/E alleles in maternal plasma is examined routinely in Institute of Hematology and Blood Transfusion in Warsaw. Preliminary results of successful fetal KEL*1 genotyping from maternal blood were obtained.

Universal RHD genotyping in fetuses

Is effective, and could dramatically reduce unnecessary anti-RhD prophylaxis

Pediatric outcome in Rhesus hemolytic disease treated with and without intrauterine transfusion

OBJECTIVE

To study the short-term morbidity in Rhesus hemolytic disease of infants treated either with or without intrauterine transfusions (IUT).

STUDY DESIGN

All term and near term infants (gestational age > or = 36 weeks) with neonatal Rhesus hemolytic disease admitted to our center between January 2000-March 2005 were retrospectively included in the study. We recorded the duration of phototherapy, the need of exchange transfusions, and the need of top-up red blood cell transfusions until 6 months of age.

RESULTS

A total of 89 infants were included, of whom 52 received at least one IUT. Duration of phototherapy in the IUT and no-IUT group was 3.8 and 5.1 days, respectively (P = .01). The percentage of infants requiring an exchange transfusion in the IUT group was 71% compared to 65% in the no-IUT group (P = .64). The percentage of infants requiring a top-up transfusion in the IUT and no-IUT group was 77% and 26.5%, respectively (P < .01).

CONCLUSION

Infants with Rhesus hemolytic disease treated with IUT required less days of phototherapy and more top-up red blood cell transfusions than neonates without IUT. However, the need for exchange transfusion was similar in both groups.

Prenatal diagnosis of the Rhesus D fetal blood type on amniotic fluid in daily practice

OBJECTIVE

To retrospectively examine the diagnostic accuracy of prenatal RhD blood type genotyping on amniotic fluid, using a combination of two polymerase chain reaction (PCR) methods in daily practice.

METHODS

Amniotic fluid was obtained from women undergoing amniocentesis. Two PCR protocols were carried out in two different laboratories. We obtained the postnatal serological RhD status. In cases with differing prenatal and postnatal test results, we investigated the possible error source by different methods. Sensitivity, specificity and the predictive values were calculated.

RESULTS

Prenatal RhD genotyping was applied in 1,640 cases, of which the postnatal serologic RhD status was obtained in 927. No discordance between both PCR methods occurred. In nine out of 927 cases differing results between PCR and serologic status were encountered. The sensitivity was 99.5%, the specificity 98.6%, and both positive and negative predictive values 99.1%.

CONCLUSION

Prenatal diagnosis of the fetal RhD blood type with PCR from amniotic fluid is highly accurate in daily practice and associated with a minimal sensitivity of 99.5% and a minimal specificity of 98.6%.

[Non invasive detection of fetal Rh using real-time PCR method]

INTRODUCTION

In the last ten years the detection of fetal origin cells and cell free fetal DNA in maternal circulation opened new horizons in non-invasive prenatal diagnosis. The diagnostic possibilities are based on the differences between the maternal and fetal origin DNA. One of the differences could be the Rh blood group and the genetical background. The Rh incompatibility is the most frequent blood group incompatibilities in the clinical practice, which can cause fetal anemia, hydrops and even fetal death.

AIMS

The aim of this study was to detect the fetal DNA in maternal circulation, to determine the Rh status of the fetus, and to compare the reliability of the method with the data found in other studies.

METHODS

Blood samples and amnionic fluid samples were collected from 30 pregnant women, with Rh negative status, between 11-22 week of gestation presented for genetic amniocentesis at the 1st. Department of Obstetrics and Gynecology, Semmelweis University. After DNA isolation real-time PCR was performed in order to detect the exon 7 of the RhD gene located on the first chromosome (1p36.11.).

RESULTS

In 24 cases the PCR reaction gave same result in case of the DNA isolated from plasma and amniotic fluid, but in six cases there was no PCR product of plasma samples and the product was detectable in amniotic fluid samples. The exon 7 was detectable in 25 cases, and there was no product in 5 cases.

CONCLUSIONS

The real-time PCR method seems to be an easy and reliable method to determine the fetal Rh blood group. The sensitivity and specificity of the method in this study is in concordance with international data. The use of more than one probe could increase the sensitivity of the method.

Reliability of second trimester triple screening for Down syndrome in rhesus-negative women

OBJECTIVE

To find out whether there is considerable influence on second trimester serum concentrations owing to the rhesus status.

STUDY DESIGN

This retrospective cohort study was performed at the Perinatology Unit of the GATA Haydarpasa Teaching Hospital. During the study interval, 2265 pregnancies met inclusion criteria. The blood samples were collected in 117 pregnancies with a maternal rhesus-negative blood group status. The control group consisted of 2148 pregnancies with a maternal rhesus-positive blood group status. Statistical analysis was performed by SPSS 11.0 statistical software.

RESULTS

Pregnancies with a maternal rhesus-negative blood group status were identified in 117 patients. The overall prevalence of pregnancies with a maternal rhesus-negative blood group status were 5.1% in our study. Only unconjugated estriol multiples of the median values were significantly decreased in rhesus-negative women (P<0.001). Alpha-fetoprotein and human chorionic gonadotrophin multiples of the median values did not differ significantly (P>0.05).

CONCLUSION

We conclude that if second trimester screening test to be used in Rh negative pregnancies, either the corrected value should be referred or double test result should be considered ignoring the unconjugated estriol result. Another option is the first trimester Down syndrome screening test.

Birth order and the severity of illness in schizophrenia

A proposed risk factor for schizophrenia is materno-foetal incompatibility. We tested the hypothesis that, in multiply affected families, later born children would exhibit a more severe form of schizophrenia than their older siblings. The effect of birth order on (1) severity of the worst ever episode of illness; (2) deterioration from premorbid level of functioning; (3) age of onset; (4) response to medication; and (5) illness course, was assessed in 150 sibling pairs with schizophrenia and schizoaffective disorder. We found that later birth order reduced the likelihood of regaining the premorbid level of functioning after an acute episode and was also associated with an earlier age of presentation. This study lends some support to the hypothesis that later birth order results in a more severe form of the disorder, although there are other possible explanations for our findings. Further work is needed to explore the possibility of maternal-foetal genotype incompatibility as a risk factor for schizophrenia.

[New approaches to prenatal diagnosis of rhesus incompatibility]

Despite generalisation of anti-D immunoprophylaxis, RhD allo-immunisation still remains the major cause of severe haemolytic disease of the fetus and of the newborn (HDFN). The routine follow up of pregnant women comprises: the ABO/D, Rh/Kell red cells typing and the search for irregular antibodies. In case of anti-D immunisation, the paternal Rh phenotype, when known, provides useful information regarding the probability for the fetus to have inherited the D antigen and thereby to be exposed to the risk of HDFN. The antibody titre, which is predictive of possible in vivo haemolysis, must be interpreted in the light of the previous obstetric history, and can lead to the decision of invasive amniocentesis. Then the measurement of the optical density (deltaOD450 nm) and the fetal RhD typing can be realised on amniotic fluid. New molecular techniques make it possible now to demonstrate the presence of fetal DNA in maternal plasma. These methods lying on non invasive procedures could advantageously be applied to the genotyping of fetal RHD during pregnancy. The present paper aims to discuss the predictive values of RHD fetal genotype in maternal plasma of RhD negative mothers. The ante-partum management of immunised pregnant women is reviewed in the light of this new molecular approach combined to Doppler ultrasonography of the fetal middle cerebral artery. This non invasive method for determining fetal RHD genotype could be systematically proposed to all RhD negative pregnant women for a better targeted prenatal follow-up and an increased efficacy of RhD prophylaxis.

Évaluation de la détermination du statut Rhésus-D fœtal sur plasma maternel par la technique d’hemi-nested PCR

AIMS

The aim of our study was to evaluate the possibility of identifying the fetal RhD status in maternal plasma using conventional hemi nested PCR analysis.

SUBJECTS AND METHODS

After informed written consent, 20 mL of peripheral blood were collected in 99 D-negative pregnant women either at an amniocentesis for prenatal diagnosis or at a prenatal checkup. Fetal DNA extracted from 400 microL of maternal plasma was analyzed by two different operators with a hemi-nested PCR extending an area of the RhD gene exon 10. The results were compared to the fetal RhD status obtained by PCR amniotic fluid analysis or blood analysis of newborns after delivery. The influence of mother's and baby's phenotype were also studied.

RESULTS

Among the 99 D-negative pregnant women, all Caucasian, 47 were in their second trimester and 52 in their third trimester (mean: 27.20 weeks of gestation +/-8.25). Sixty-nine fetuses were D-positive and thirty D-negative. The sensitivity and specificity of our technique were respectively 100% and 86.7% and 15% of discordant results were observed between the two operators. Four false positives were observed. According to maternal phenotype, a fetal unexpressed RHD gene was suspected in only one case because of a particular fetal phenotype (ddCcEe).

CONCLUSION

A conventional hemi nested PCR analysis of maternal plasma could be used for accurate fetal RhD status. However this procedure is difficult to apply for routine analysis because of the importance of anti-contamination measures required to obtain good results. Real time quantitative PCR analysis on fetal DNA is more suitable. Whatever the operating procedure used, polymorphism of RhD gene may follow in either false negative from presence of rearranged gene or false positive from occasional presence of a non functional RHD gene.

[Management of rhesus alloimmunisation by spectrophometry: about one case at the Yopougon Teaching Hospital, Côte-d'Ivoire]

The authors report a care management of a patient presenting a severe alloimmunisation treated by spectrophotometry, a very efficient method but difficult of access in developing countries. Beyond the restrictive paraclinical exams which do not allow an efficient monitoring of this pathology, the lack of alloimmunisation prevention during illegal abortions and the lack of information about patients'medical files are highly responsible for the difficult management of Rhesus- negative patients. However the authors remind that only the scan at best combined with the Doppler, are effective exams helping to avoid the constraints of spectrophotometry. Although quite well-known this pathology induces very severe foetal consequences and may involve the obstetric prognosis of young women. The caesarian section will still remain for a long time the only means to prevent foetus from alloimmunisation complications in developing countries.

Diagnostic accuracy of noninvasive fetal Rh genotyping from maternal blood--a meta-analysis

OBJECTIVE

The purpose of this study was to determine the reported diagnostic accuracy, the validity, and the current limitations of fetal Rh genotyping from peripheral maternal blood based on the existing English-written publications.

STUDY DESIGN

A search of the English literature describing fetal RhD determination from maternal blood was conducted. From each study, we determined the number of samples tested, fetal RhD genotype, the source of the fetal DNA (maternal plasma, serum, or fetal cells), gestational age, and confirmation of fetal Rh type. The presence of alloimmunization and exclusions of tested samples were noted. For the meta-analysis we calculated composite estimates using 2 random effects models, weighted GLM and Bayesian. Sensitivity, specificity, positive and negative predictive values were calculated.

RESULTS

We identified 37 English-written publications that included 44 protocols reporting noninvasive Rh genotyping using fetal DNA obtained from maternal blood on a total of 3261 samples. A total of 183 (183/3261, 5.6%) samples were excluded from the meta-analysis. The overall diagnostic accuracy after exclusions was 94.8%. The gestational ages ranged between 8 and 42 weeks gestation. Maternal serum and plasma were found to be the best source for accurate diagnosis of fetal RhD type in 394/410 (96.1%) and 2293/2377 (96.5%), respectively. There were 719/783 (91.8%) alloimmunized patients that were correctly diagnosed. There were 16 studies that reported 100% diagnostic accuracy in their fetal RhD genotyping.

CONCLUSION

The diagnostic accuracy of noninvasive fetal Rh determination using maternal peripheral blood is 94.8%. Its use can be applicable to Rh prophylaxis and to the management of Rh alloimmunized pregnancies. Improvements of the technique and further study of structure and rearrangements of the RhD gene may improve accuracy of testing and enable large-scale, risk-free fetal RhD genotyping using maternal blood.

ACOG Practice Bulletin No. 75: Management of Alloimmunization:

When any fetal blood group factor inherited from the father is not possessed by the mother, antepartum or intrapartum fetal-maternal bleeding may stimulate an immune reaction in the mother Maternal immune reactions also can occur from blood product transfusion. The formation of maternal antibodies, or"alloimmunization,' may lead to various degrees of transplacental passage of these antibodies into the fetal circulation. Depending on the degree of antigenicity and the amount and type of antibodies involved, this transplacental passage may lead to hemolytic disease in the fetus and neonate. Undiagnosed and untreated, alloimmunization can lead to significant perinatal morbidity and mortality. Advances in Doppler ultrasonography have led to the development of noninvasive methods of management of alloimmunization in pregnant women. Together with more established protocols, Doppler ultrasound evaluation may allow for a more thorough and less invasive workup with fewer risks to the mother and fetus. Prevention of alloimmunization is addressed in another Practice Bulletin (1).

Studies of the extraction of bilirubin from human amniotic fluid

The recovery of unconjugated bilirubin from human amniotic fluid was studied using dichloromethane, chloroform/isopropanol (3:1 vol/vol), and chloroform/ methanol (3:1 vol/vol) extraction of human amniotic fluid that had been supplemented with bilirubin at various concentrations. Results were compared with those obtained with conventional chloroform extraction. Mean recoveries were found to be only 28% for chloroform and 25% for dichloromethane. When the polarity of chloroform was increased by the addition of an alcohol, the mean recovery increased to only 40% for chloroform/isopropanol and 38% for chloroform/ methanol. These results suggest that extraction methods for determination of amniotic fluid "delta OD(450)" (visible spectrophotometric absorbance [optical density] of bilirubin at 450 nm) tend to underestimate the result when compared with the nonextraction (direct-scan) method, on which the Liley Prognostication Chart is based. This finding should be clinically significant, particularly if extraction and direct-scan methods are used to monitor the condition of the same patient.

The issue of anti-D: an integrated seamless approach from recognition of need to bedside administration

BACKGROUND

The appropriate and timely administration of Anti-D immunoglobulin to Rhesus (D) negative women who have delivered Rhesus (D) positive babies is a vital part of obstetric care. Anti-D has an especially high profile in Ireland because of the tragic inadvertent transmission of Hepatitis C to Irish women in past decades.

AUDIT

We have reviewed our policy and procedures pertaining to the administration of Anti-D for sensitising events during pregnancy and postnatally, in the Mid-Western Health Board in 1999/2000. As a result, major changes were made in the storage, issue, recording and administration of Anti-D. New procedures in the transfusion laboratory and in the maternity hospital have been accepted by scientists and midwives and supported by haematology and obstetric medical staff. The pharmacy and haematology laboratory no longer have a role in this programme. IMPLEMENTATION OF MULTI-DISCIPLINARY CHANGE MANAGEMENT: As a result of these changes, the storage, issuing and tracking of Anti-D has become the responsibility of the hospital blood bank. Measurement offoeto-maternal haemorrhage (FMH) is now the responsibility of bio medical scientists in blood bank, utilising both flow cytometry (increasingly recognised as the gold standard method) and the Kleihauer method (Kleihauer-Betke). The programme has moved from a doctor-administered IV Anti-D Ig, to a midwife-administered IM preparation. Prescription remains the responsibility of the doctor. These changes are facilitated by the protocol guided issue of the appropriate dose of Anti-D Ig by bio medical scientists to midwives. The issue of the Anti-D Ig occurs simultaneously with issue of results of mother and baby's serology testing and estimation of volume of FMH. These major changes have been guided by audit and needs assessment and require close liaison between medical, nursing and laboratory scientific staff in haematology, transfusion and obstetrics. CRITICAL INCIDENT AUDIT-CASE REPORT: Before new procedures became official policy, a critical incident audit allowed us to pilot our protocol and to revise it using draft new procedures. In this critical incident we describe successful management of a patient with a large foeto-maternal haemorrhage. This incident supported the need for the procedural enhancements already underway. This critical incident re-emphasised the need for the planned systems improvements to be introduced quickly.

Diagnosis and management of Rh alloimmunization

OBJECTIVE

To assess the current problem of alloimmunization in a tertiary referral center in Croatia. The results obtained were compared to data published worldwide.

METHODS

Retrospective case analysis included women with Rhesus (Rh) alloimmunization treated in our department from January 1997 to January 2003. Data of interest included the incidence, prevention, diagnosis and treatment, with the final point being perinatal mortality and morbidity.

RESULTS

23 pregnant women with alloimmunization were identified. The incidence was 0.138% of deliveries in the same time period. The median gestational age at diagnosis/referral was 22 (range 9-37) weeks. Anti-D antigen, alone or in combination with the other antigens, was responsible for more than 90% of the alloimmunization cases included. A defined protocol for prevention of Rh D immunization after previous delivery was not followed properly in 9/19 cases. A particular problem was prophylaxis after previous pregnancy termination (TOP), whereby only 1/14 woman received adequate prophylaxis and only after 2 of 5 TOPs. Regarding fetal treatment, 9/23 women had a total of 24 intrauterine intravascular blood transfusions. Overall, perinatal mortality was 13%, and the median gestational age at delivery was 34 (range 31-40) weeks. In all there were 31 fetal exchange transfusions after delivery performed in 14/20 newborns.

CONCLUSION

Despite precise diagnostic criteria and modern therapeutic options, alloimmunization remains a problem in Croatia. It is still related with a high perinatal mortality and morbidity. The main problem is inadequate prevention.

First trimester ultrasound screening for fetal aneuploidy and middle cerebral artery Doppler assessment for fetal alloimmunization

PURPOSE OF REVIEW

Traditional methods of fetal evaluation require invasive procedures (e.g. amniocentesis) with an inherent, albeit low, risk of complications and pregnancy loss. As medical knowledge and ultrasound technology have advanced, noninvasive modes of fetal evaluation have become increasingly used. Two disorders in which this has been most applied are fetal aneuploidy and alloimmunization to red blood cell antigens.

RECENT FINDINGS

First-trimester screening protocols for fetal aneuploidy combine ultrasound measurement of the fetal nuchal translucency with the measurement of two maternal serum hormones, free beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A. This combination detects approximately 85% of women pregnant with fetuses with trisomy 21. An increase in the velocity of fetal middle cerebral artery blood flow occurs in the setting of moderate to severe fetal anemia and can be measured with Doppler ultrasound. Middle cerebral artery evaluation is equally sensitive in the prediction of anemia as amniocentesis for bilirubin breakdown products and has less associated risk. It has an additional benefit because it can also be applied to causes of anemia other than hemolysis.

SUMMARY

Noninvasive methods of fetal assessment are becoming increasingly commonplace. There has been a dramatic decrease in the use of prenatal diagnostic services as screening strategies have become available. Doppler assessment of the velocity of blood flow through the fetal middle cerebral artery will allow for more judicious application of invasive procedures to pregnancies at significant risk for anemia.

Noninvasive prenatal diagnosis of fetal Rhesus D: ready for Prime(r) Time

Rhesus (Rh) D blood group incompatibility between the pregnant woman and her fetus is a significant problem due to the possibility of maternal alloimmunization and consequent hemolytic disease of the newborn. The RhD-negative blood group is found in 15% of whites, 3-5% of black Africans, and is rare in Asians. Advances in both our understanding of the RHD locus and its variants, as well as technical improvements in the extraction and amplification of cell-free fetal DNA in maternal plasma, have led to incorporation of noninvasive diagnosis of RHD genotype into routine prenatal care in the United Kingdom, France, and the Netherlands. In this commentary we examine the experience to date with large-scale clinical trials performed in the European Union, describe approaches to reduce false-positive and false-negative results, and review ongoing research to standardize assays and reduce costs using automated assays. False-negative cases are mainly due to either a lack of fetal DNA in the maternal sample due to early gestation or insensitive methods. False-positive cases are due to genotypic variants observed in individuals of African ancestry. Noninvasive prenatal diagnosis of fetal Rhesus D genotype is sensitive and accurate and has been widely validated in Europe. The United States should begin to undertake clinical trials to bring this technology to patient care as soon as possible.

Red Blood Cell Alloimmunization in Pregnancy

Red blood cell (RBC) alloimmunization in pregnancy continues to occur despite the widespread use of both antenatal and postpartum Rhesus immune globulin (RhIG), due mainly to inadvertent omissions in administration as well as antenatal sensitization prior to RhIG given at 28 weeks' gestation. Additional instances are attributable to the lack of immune globulins to other RBC antigens. Evaluation of the alloimmunized pregnancy begins with the maternal titer. Once a critical value [32 for anti-Rh(D) and other irregular antibodies; 8 for anti-K and -k] is reached, fetal surveillance using serial Doppler ultrasound measurements of the peak velocity in the fetal middle cerebral artery (MCA) is standard. In the case of a heterozygous paternal phenotype, amniocentesis can be performed to detect the antigen-negative fetus that requires no further evaluation. MCA velocities greater than 1.5 multiples of the median necessitate cordocentesis, and if fetal anemia is detected, intrauterine transfusion therapy is initiated. A perinatal survival of greater than 85% with normal neurologic outcome is now expected. Future therapies will target specific immune manipulations in the pregnant patient.

Pregnancy outcome for Rh-alloimmunized women

OBJECTIVE

To compare perinatal results of Rh-alloimmunized pregnancies managed with spectrophotometric amniotic fluid analysis or fetal middle cerebral artery Doppler ultrasonographic velocimetry.

METHOD

A descriptive observational study involving 291 consecutive Rh-negative pregnancies. Group 1 consisted of 74 isoimmunized women managed with amniotic fluid spectrophotometry; group 2 of 25 isoimmunized women managed with Doppler ultrasonography; and group 3 of 192 nonimmunized Rh-negative women. The variables analyzed were need for intrauterine or neonatal transfusion, mode and time of delivery, birth weight, neonatal hematocrit, and perinatal mortality.

RESULTS

Need for intrauterine transfusion, birth weight, prematurity, rate of cesarean section, and perinatal mortality were similar in groups 1 and 2. Neonatal hematocrit was significantly lower and the need for neonatal transfusion was significantly higher when spectrophotometry rather than Doppler ultrasonographic velocimetry was used.

CONCLUSION

Fetuses managed with Doppler ultrasonographic velocimetry had a higher hematocrit at birth and a lesser need for neonatal transfusion, suggesting that this noninvasive method of monitoring fetal anemia is a better choice.

Anti-C(w) alloimmunization presenting as hydrops fetalis

C(w) is a low frequency red cell antigen that belongs to the Rh blood groups system. While not uncommon, anti-C(w) is rarely associated with clinically significant haemolytic disease of the newborn (HDN). When it does occur, it is often subclinical or of mild to moderate clinical severity. In the majority of pregnancies it is considered to be a naturally occurring antibody and has not been reported to cause hydrops fetalis or stillbirth. We report a case of anti-C(w) alloimmunization, which was associated with significant anaemia and hydrops fetalis, presenting at 35 wk gestation.

CONCLUSION

Pregnancies affected by anti-C(w) merit closer scrutiny. Consideration should be given to performing more frequent antenatal ultrasound assessments to detect hydrops fetalis. This may help to support the need for more invasive procedures (cordocentesis and intrauterine transfusions).

The role of preimplantation genetic diagnosis in the management of severe rhesus alloimmunization: first unaffected pregnancy: Case report

Rhesus (Rh) D alloimmunization may cause haemolytic disease of the fetus and newborn if the fetal Rh blood type is positive. Although the incidence of severe RhD alloimmunization has decreased with prophylactic anti-D immunoglobulin administration during and after pregnancy, sensitization still occurs in a small group of women. In such women, Rh disease will continue to be significant problem and for their babies who may be affected. Preimplantation genetic diagnosis (PGD) may be utilized to avoid materno-fetal blood group incompatibility in an RhD-sensitized woman. Biopsy of a single cell from early cleavage-stage embryos screening for RhD-negative embryos allows the transfer of only RhD-negative embryo(s) into the uterus. This avoids any complications related to haemolytic disease of the fetus and newborn. This article describes the first reported case of an unaffected pregnancy using PGD for Rh disease. IVF and embryo transfer resulted in a clinical pregnancy and the birth of a healthy girl confirmed to be blood type RhD negative. PGD in couples with a heterozygous RhD-positive male partner provides an option for avoiding haemolytic disease of the newborn in RhD alloimmunized mothers.

Non-invasive diagnosis of fetal anemia due to maternal red-cell alloimmunization

OBJECTIVE

To determine the value of measurement of velocity of the middle cerebral artery (MCA) in the prediction of fetal anemia in alloimmunized pregnancies without ultrasound evidence of hydrops and to see if this could replace the invasive techniques in the diagnosis and management of this condition.

METHODS

In a prospective cohort study, 65 non-hydropic fetuses with red blood cell alloimmunization were evaluated with ultrasound and Doppler imaging. This study was carried out at Feto Maternal Medicine Unit at Women's Hospital, Hamad Medical Corporation, Doha, Qatar from January 2003 to December 2003. Middle cerebral artery-peak systolic velocity (PSV) was measured. We interfered only if there is a sign of fetal anemia as indicated by changes in blood velocity in MCA using the table designed by Giancarlo Mari or the fetus developed signs of hydrops fetalis. Immediately after delivery, the blood was taken from umbilical cord for full blood count, blood group, bilirubin and antibodies level. Results before first fetal blood sampling (FBS) or delivery were analyzed.

RESULTS

Sixty-five patients met the inclusion criteria for the study and were managed. Sixty-three women were alloimmunized with rhesus (Rh)-D antibodies and 2 with anti-C. With the conventional management, all 65 patients undergone amniocentesis to determine bilirubin levels. However, with non-invasive management, 60 women were safely prevented from undergoing invasive testing or invasive procedures. Amniocentesis was performed for only one (1.54%) patient, despite having a normal MCV-PSV which was carried out solely due to the care provider was insisting on this procedure and the result was normal. Planning delivery based on MCA-PSV allowed us to deliver 97% (63/65) of these babies without any signs of severe anemia between 28-38 weeks. Two (3%) of the fetuses were diagnosed as severely anemic with MCA-PSV. In both cases, anemia was confirmed by FBS and intra uterine transfusion was carried out immediately to the test. Only 2 babies were diagnosed anemic after birth and underwent blood transfusion.

CONCLUSION

Doppler evaluation of MCA-PSV is effective in the prediction of fetal anemia in red blood cell alloimmunization. Using this technique will reduce the number of invasive procedures needed with the added risks of these procedures with good fetal outcome.

Non-invasive fetal RHD and RHCE genotyping from maternal plasma in alloimmunized pregnancies

BACKGROUND

In this prospective study, we assessed the feasibility of fetal RH genotyping by analysis of DNA extracted from maternal plasma samples of alloimmunized pregnant women using real-time PCR and primers and probes targeted toward RHD (exon 7 and exon 10) and RHCE (intron 2 and exon 5) genes.

METHODS

We analysed 23 alloimmunized pregnant women (16 anti-D, 5 anti-D + C, 2 anti-E) at risk of haemolytic disease of the newborn (HDN) within 11th and 37th week of pregnancy and correlated the results with serological analysis of cord blood.

RESULTS AND CONCLUSION

Detection of the presence of the RHD gene, the C and/or E alleles of the RHCE gene in maternal plasma samples is highly accurate and enables implementation in a clinical diagnostic algorithm for following pregnancies at risk for HDN. The absence of RHD gene, the C and/or E alleles of RHCE gene in the current pregnancy excludes the risk of HDN caused by anti-D, anti-C and/or anti-E alloantibodies and the performance of invasive fetal-blood sampling.

A case of extreme unconjugated fetal hyperbilirubinemia

We present an unusual case of severe unconjugated hyperbilirubinemia and normal hemoglobin at birth in a premature newborn with Rh incompatibility. We speculate that the possible mechanism is due to placental dysfunction. To our knowledge, this is the highest reported unconjugated bilirubin level at birth.

Fetal hemolytic disease due to anti-Rh17 alloimmunization

OBJECTIVE

To delineate clinical features of a case of fetal hemolytic disease due to anti-Rh17, along with a review of relevant studies published in English and Japanese.

METHODS

We present clinical features of a -D-/-D- phenotype woman with anti-Rh17 alloimmunization during pregnancy. Relevant English literature in the MEDLINE database was reviewed, while Japanese studies were searched in the Japana Centra Revuo Medicina database.

RESULTS

A Japanese -D-/-D- woman with anti-Rh17 (Hro) was treated during pregnancy. Serial ultrasonography, antibody titers, amniocenteses, and cordocenteses were conducted for perinatal management. Amniocentesis results demonstrated a high delta optical density level of 450 in the amniotic fluid, while cordocentesis revealed alloimmunization between the mother and the fetus as well as fetal hemolytic anemia. Blood flow velocity in the middle cerebral artery indicated a rapid development of fetal anemia. The newborn demonstrated severe anemia and hyperbilirubinemia, which were successfully treated with exchange transfusions. Two cases of prenatally diagnosed fetal hemolytic disease due to anti-Rh17 were found published in English and 5 in Japanese.

CONCLUSION

A -D-/-D- phenotype patient with anti-Rh17 was successfully managed during pregnancy and a good outcome for the neonate was achieved. Our results and a review of related literature led to the following suggestions. The first pregnancy in a -D-/-D- woman may be affected, an anamnestic immune response can easily occur during pregnancy, the level of anti-Rh17 titer is indicative of the degree of fetal hemolysis, and appropriate intrauterine intervention is warranted for achievement of a good outcome.

A retrospective review of isoimmunized pregnancies managed by middle cerebral artery peak systolic velocity

OBJECTIVE

The purpose of this study was to determine the clinical outcome of isoimmunized pregnancies managed primarily by middle cerebral artery peak systolic velocity.

STUDY DESIGN

A retrospective chart review was conducted of isoimmunized pregnancies that underwent ultrasound examinations from January 1, 2001, through May 1, 2003. Ultrasound reports, laboratory tests, and maternal and neonatal charts were reviewed.

RESULTS

Women with a clinically significant red blood cell antibody and titer value were included. The study population consisted of 39 women (40 pregnancies, 42 fetuses). Patients with a middle cerebral artery peak systolic velocity of > or =1.5 MoM were offered amniocentesis. Seven pregnancies had an abnormal middle cerebral artery peak systolic velocity. Three of these infants had significant anemia. Six of the 7 pregnancies required an exchange transfusion. None of the 33 pregnancies (35 neonates) with normal middle cerebral artery peak systolic velocity measurements resulted in a neonate with significant anemia or severe hyperbilirubinemia.

CONCLUSION

The clinical outcome of these pregnancies supports the use of middle cerebral artery peak systolic velocity measurements in the management of isoimmunized pregnancies.

Recent developments in fetal medicine

Several advances have been made in the field of fetal medicine since the last BMJ review on the subject. This review covers advances in prenatal screening, imaging techniques, management of multiple pregnancies, and fetal therapy