Fetomaternal hemorrhage: evaluation of recurrence within a large integrated healthcare system.

BACKGROUND: Fetomaternal hemorrhage is associated with severe fetal morbidity and mortality. The recurrence risk of fetomaternal hemorrhage is unknown. OBJECTIVE: We sought to establish the recurrence rate of fetomaternal hemorrhage in a large integrated healthcare system over a 10-year period. STUDY DESIGN: In this retrospective study within the Kaiser Permanente Northern California medical system, cases of fetomaternal hemorrhage were defined by either an elevated fetal hemoglobin level as determined by flow cytometry for a concerning pregnancy outcome (preterm delivery, perinatal demise, neonatal anemia, or transfusion within the first 2 days of life) or by perinatal demise with autopsy findings suggestive of fetomaternal hemorrhage. The outcomes of subsequent pregnancies were reviewed for features of recurrence. RESULTS: Within the 2008 to 2018 birth cohort of 375,864 pregnancies, flow cytometry testing for fetal hemoglobin levels was performed in 20,582 pregnancies. We identified 340 cases of fetomaternal hemorrhage (approximately 1 in 1100 births). Within the cohort of 340 affected pregnancies, perinatal loss was recorded for 80 (23.5%) pregnancies and 50 (14.7%) pregnancies delivered neonates who required transfusion. The affected patients had 225 subsequent pregnancies of which 210 were included in the analysis. Of these, 174 (82.9%) advanced beyond the threshold of viability and were delivered within our healthcare system. There was 1 case of recurrent fetomaternal hemorrhage identified. The recurrent case involved a spontaneous preterm delivery of an infant who was noted to have an elevated reticulocyte count but was clinically well. CONCLUSION: Within our large integrated healthcare system, approximately 1 in 1100 pregnancies was affected by fetomaternal hemorrhage within a 10-year period, which is comparable with previous studies. We identified 1 case of recurrence, yielding a recurrence rate of 0.5%. This infant did not have features of clinically important fetomaternal hemorrhage. This information can inform counseling of patients with affected pregnancies.

The prevalence of an elevated F cell population in a maternal and gynaecology cohort.

OBJECTIVES: This study aimed to determine F cell prevalence in a cohort of maternal and gynaecology specimens using QuikQuant anti-HbF flow cytometry (FC) kit and to investigate if the presence of maternal F cells can lead to fetomaternal haemorrhage (FMH) overestimation. BACKGROUND: The gold standard to estimate FMH is the Kleihauer-Betke test (KBT). The KBT has proved to be insufficiently sensitive to detect low numbers of circulating fetal cells due to the presence of maternal F cells. At present, the prevalence of false positive KBT results due to raised maternal F cell population, defined as >5%, is poorly characterised. METHODS: A total of 120 specimens were tested for the presence of F cells and fetal cells by KBT and anti-HbF FC. The results calculated were compared to determine FMH overestimation. RESULTS: Of our cohort, 32% showed an elevated F cell population, of which 69% (27 of 39) were clinically significant according to KBT (>2 mL FMH). The mean FMH volumes by KBT and anti-HbF FC were 3·90 mL (0·20-35·40 mL) and 4·09 mL (0·20-9·70 mL), respectively. CONCLUSION: The study highlighted that an elevated F cell level could be found in the cohort tested, with an F cell level of >10% causing significant FMH overestimation by KBT.

Fetomaternal hemorrhage among pregnant women in Accra, Ghana.

OBJECTIVE: To determine the occurrence of and risk factors for fetomaternal hemorrhage (FMH) among pregnant women at Korle Bu Teaching Hospital in Accra, Ghana. METHODS: A prospective study of FMH among pregnant women without hemoglobinopathies in the second trimester attending prenatal care between October 2015 and May 2016 performed using the Kleihauer-Betke test. Volume of FMH was estimated; ABO and Rh blood groups of participants were determined. A data extraction form and structured questionnaire were used to collect demographic and clinical information, and data on risk factors. RESULTS: Of 151 participants, 32 (21.2%) had FMH. Almost 18% (n=27) had FMH at baseline (16-24 weeks), 10% (10/100) at 28-32 weeks, and 11.1% (11/99) at 34-37 weeks of pregnancy. Volume of FMH was less than 30 mL in 30 (19.9%) women, whereas it was greater than 30 mL in 2 (1.3%) women. No identifiable patient-specific factors were associated with occurrence of FMH. CONCLUSION: FMH is common among pregnant women in Ghana and can occur as early as 16 weeks, without identifiable risk factors. RhD negative women who may be pregnant with RhD positive fetuses should be screened early in pregnancy, not only at delivery, for occurrence of FMH.

Blood Group Antigen Matching Influence on Gestational Outcomes (AMIGO) study.

BACKGROUND: Red blood cell (RBC) antigen matching policies to prevent alloimmunization in females of childbearing potential (FCP) vary between centers. To inform transfusion centers responsible for making decisions about matching policies for FCPs, the causal stimulus of the antibodies implicated in severe hemolytic disease of the fetus and newborn (HDFN) must be determined. STUDY DESIGN AND METHODS: We conducted a multinational retrospective study of women with offspring affected by severe HDFN requiring neonatal exchange transfusion and/or intrauterine transfusion. Mothers treated at centers that provide extended antigen-negative RBCs (MATCH, five centers) and those that do not (NoMATCH, nine centers) were compared. RESULTS: A total of 293 mothers had at least one affected pregnancy: 179 at MATCH centers and 114 at NoMATCH centers. Most alloimmunization (83%) was attributed to previous pregnancy: 3% to transfusion (two cases at MATCH, six at NoMATCH centers) and 14% undetermined (both antecedent transfusion and pregnancy). Only 50 mothers had received transfusions; 13 had HDFN due to anti-K at MATCH and four at NoMATCH centers. Most (12/13, 92%) of the anti-K HDFN cases at MATCH centers had K+ paternal antigen status. Mothers at the MATCH centers do not appear to be protected from HDFN due to K, C, c, and E antibodies, although the low number of FCPs who received transfusions precluded drawing firm conclusions. CONCLUSION: The causal stimulus of antibodies that cause HDFN is predominantly from previous pregnancy. Although extended RBC matching for FCPs may impart some protection from allosensitization, we were unable to show a positive effect, possibly because matching policies are not uniform and there was a small number of mothers who previously received transfusions.

Red cell alloimmunization in RhD positive pregnant women and neonatal outcome.

The frequency of red blood cell (RBC) alloimmunization in RhD positive pregnant women is not known in our population. We planned to determine its frequency and correlation with neonatal outcome. We included 1000 RhD positive pregnant women: 500 had 'normal pregnancy' (Group I) and another 500 had 'high risk pregnancy' (Group II). ABO and extended Rh phenotyping were done by tube technique, antibody screening and identification by gel technique. For alloimmunized women, the paternal and neonatal ABO and extended Rh typing were done. Neonatal direct antiglobulin test (DAT) was also done and their clinical outcome observed. The frequency of RBC alloimmunization was 0.7% (7/1000) and all these women were from group II (p = 0.015). The alloantibodies were anti-E (85.7%), anti-c (71.4%), anti-Cw (14.3%) and anti-S (14.3%). Also, 6 women had history of transfusion (p < 0.01). Of the 7 neonates born to alloimmunized mothers, 4 (57.14%) had a positive DAT. The mean duration of phototherapy was higher in the DAT positive neonates (p < 0.01) and 2 (50%) required exchange transfusion. Thus, the frequency of alloimmunization was 0.7% in RhD positive pregnant women. High risk pregnancies and antenatal patients having a history of blood transfusion should be considered for regular antibody screening.

Occult fetomaternal hemorrhage in women with pathological placenta with respect to permeability.

AIM: Women with pre-eclampsia (PE), placenta previa (PP), placental abruption (PA), and placental mesenchymal dysplasia (PMD) have been described as having placental permeability dysfunction. This study was performed to determine whether occult fetomaternal hemorrhage (FMH) is common in women with such complications and in women with non-reassuring fetal status. METHODS: Forty-one antenatal and 39 postnatal blood samples were obtained from 46 women, including 11 with placental permeability dysfunction (5, 3, 2, and 1 with PE, PP, PA, and PMD, respectively) and 35 controls without such complications. To estimate the amount of fetal red blood cells, flow cytometry was performed using the fetal cell count system with two antibodies against fetal hemoglobin and carbonic anhydrase and the ß-γ system with two monoclonal antibodies against hemoglobin ß-chain and hemoglobin γ-chain. A diagnosis of FMH was made when the fraction size of the isolated cell population on scatter plots expressing fetal hemoglobin alone or hemoglobin γ-chain alone accounted for ≥0.02% of the total cell population on scatter plots. RESULTS: FMH was identified in five women, including one each with PE, PA, PP, PMD, and no complications. Thus, the prevalence rate of FMH was significantly higher in women with complications than in controls (36% [4/11] vs 2.9% [1/35], respectively, P =  0.009). The FMH occurrence rate did not differ between women with and without non-reassuring fetal status (7.7% [1/13] vs 12% [4/33], respectively, P =  1.000). CONCLUSION: The risk of fetal red blood cells trafficking into the maternal circulation may be increased in women complicated with PE, PA, PP, and PMD.

Demographic and Behavioral Predictors of Severe Fetomaternal Hemorrhage: A Case-Control Study.

BACKGROUND: Fetomaternal hemorrhage (FMH) signifies failure of the placental barrier with whole blood transfer. Fetal anemia following FMH is associated with significant morbidity and mortality. If FMH is identified early, fetal anemia can be treated to minimize adverse outcomes. Risk factors for FMH are not known, limiting efforts to provide targeted screening for FMH. OBJECTIVE: To identify maternal and/or pregnancy characteristics associated with FMH that are recognizable prior to fetal morbidity. METHODS: This is the first published case-control study of FMH. Cases were identified from a prospectively maintained database of all hospital births between 1988 and 2010. Each case was matched to 4 controls by date and time of birth, allowing for assessment of a wide range of clinical and demographic data. Logistic regression modeling was used to assess the association between demographic and clinical characteristics and the diagnosis of FMH. RESULTS: A total of 23 mother-baby pairs impacted by FMH and 92 matched controls were evaluated. Compared to controls, case mothers were more likely to have private insurance and to work outside the home and at night during pregnancy. Cases were more likely to be delivered preterm, but preterm labor was not more common among cases. There was no difference in race/ethnicity of cases compared to controls. CONCLUSIONS: Severe FMH is associated with significant morbidity and mortality of the affected neonate. Women with FMH were more likely to work outside the home during pregnancy than women with normal pregnancies. This finding has implications for third-trimester screening of pregnant women who work in strenuous fields.

A pilot prospective study of fetomaternal hemorrhage identified by anemia in asymptomatic neonates.

OBJECTIVE: Fetomaternal hemorrhage (FMH) is a poorly understood condition in which fetal erythrocytes transfer to the maternal circulation via a faulty placental barrier. Little is known about the true incidence, epidemiology or pathophysiology of FMH in the general pregnant population as existing studies are based on retrospective cohorts and manifest diagnosis and selection bias. The objective of this study was to evaluate the practicability of a prospective study of FMH in the general population based on antepartum maternal blood testing and neonatal anemia. STUDY DESIGN: Prospective cohort study. RESULT: Nineteen pregnant women were enrolled prior to the term delivery of 20 well infants. Five neonates were unexpectedly anemic on first postnatal testing. Antenatal maternal blood samples associated with two of the five anemic newborns had positive Kleihauer-Betke testing while no newborn with a normal postnatal blood count had an associated abnormal Kleihauer-Betke test. CONCLUSION: Clinically significant FMH may be more common than previously thought. Prospective epidemiological study of FMH is feasible.

Prevalence of maternal red cell alloimmunisation: a population study from Queensland, Australia.

The aim of this study was to determine the current prevalence of red cell antigen alloimmunisation in Australia. Blood group (ABO and RhD) and red cell antibody screen results of pregnant women who presented at public hospitals in Queensland between the period of January 2011 and June 2013 were evaluated retrospectively. Antibody prevalence in pregnancy was compared to other published studies. A total of 482 positive antibody screens from 66,354 samples (0.73%) were identified. The prevalence of antibodies was: anti-E 27.6%; anti-D 10.4%; anti-Kell 9.5%; anti-c 8.7%; anti-Duffy 3.1%, including Fy and Fy; anti-MNS 7.9%, including M, N, S and s; anti-Lewis 6%, including Le and Le; and multiple antibodies (16%, including anti-D). Compared to other studies, including one from Australia in 1977, the anti-D alloimmunisation rate had dropped significantly, with little change in anti-c and some increase in anti-E and anti-Kell cases. Continued vigilance is required to ensure eligible RhD negative women receive prophylaxis according to the current RhD immunoprophylaxis guidelines, especially those who have a fetomaternal haemorrhage (FMH). RhD positive women that are at risk of developing an antibody during pregnancy should have their pregnancy monitored according to published guidelines. Once antibodies are identified, consideration should be given to paternal antigen status in an attempt to identify the pregnancy that will be at risk of alloimmunisation.

Risk of maternal alloimmunization in Southern Pakistan - a study in a cohort of 1000 pregnant women.

BACKGROUND: Haemolytic disease of the fetus and the newborn [HDFN] is caused by incompatibility of maternal and fetal erythrocytes. Red blood cell alloimmunization is a well-known cause of HDFN. Due to heterogeneity of populations, the spectrum of alloimmunization varies around the world. This study aimed to determine the frequency of alloimmunization in pregnant women and to determine the risk of HDFN in our population. STUDY DESIGN AND METHODS: This was a descriptive study conducted at Aga Khan University Hospital Karachi. Blood type and red cell antibody screening was determined on every pregnant woman at her first antenatal visit. Red cell antibody identification was performed on positive screening results. RESULTS: A total of 1000 pregnant females including 633 (63.3%) multigravida were studied. Blood type B was predominant (n = 374 or 37.4%) and D negative was observed in 136 women (13.6%). No red cell antibody was detected in 982 females (98.2%). 20 red cell antibodies were detected in 18 women (1.8%). The incidence of non-anti-D was 16/1000 [1.6%] in all pregnant females. The non-anti-D alloantibodies included anti-M (n = 3; 15%), anti-Lewis(a) (n = 3; 15%), anti C ( n = 1; 5%), anti-E (n = 1; 5%), anti-e (n = 1; 5%), anti-Lewis(b) (n = 1; 5%) and nonspecific antibodies (n = 6; 30%). The incidence of anti-D was 4/136 or 2.9% in D negative blood type. After excluding prior sensitization due to blood transfusions, risk remained was 2.2%. Antibodies of clinical significance were identified in 9 (0.9%) females. CONCLUSIONS: In our cohort, frequency of red cell alloimmunization during pregnancy was 1. 8% out of which 0.9% were clinically significant antibodies posing a risk for HDFN. Despite prenatal and post natal prophylaxis, risk of sensitization with D antigen in D negative women was high at 2.2%. We recommend that all pregnant women should be screened for irregular antibodies irrespective of the rhesus type.

A correlation between severe haemolytic disease of the fetus and newborn and maternal ABO blood group.

OBJECTIVE: To analyse anti-D quantification levels and frequency of intrauterine transfusion (IUT), per maternal ABO blood group. BACKGROUND: Maternally derived red cell allo-antibodies can target fetal red cell antigens in utero leading to haemolytic disease and fetal anaemia. When a clinically significant allo-antibody is formed the priority is ascertaining the risk to the fetus and maternal ABO blood groups are not considered relevant. MATERIALS AND METHODS: This was a 10-year retrospective, observational study carried out on women referred for anti-D quantification (n = 1106), and women whose fetuses required an IUT to treat fetal anaemia (n = 62) due to anti-D, in the Republic of Ireland. RESULTS: Relative to the overall incidence of RhD allo-immunisation by blood group, women of blood group A were more likely to require IUT compared with those who were blood group O (P = 0.002). CONCLUSION: It is known that ABO feto-maternal compatibility can influence the incidence and level of red cell allo-antibodies in pregnancy; however, it does not account for the significantly high rate of severe haemolytic disease requiring IUT seen in blood group A women.

Impact of physician awareness on diagnosis of fetomaternal hemorrhage.

BACKGROUND: Fetomaternal hemorrhage (FMH) is a poorly understood condition in which the placenta allows transmission of fetal whole blood to the mother. FMH can cause fetal anemia resulting in critical illness, death or lifelong disability. Ascertainment of the incidence of FMH is limited by reliance on retrospective studies that are dependent on a diagnosis of FMH being made at the time of patient presentation. OBJECTIVE: To determine whether the diagnosis of FMH is made more frequently after an educational intervention to increase physician awareness of the condition. METHODS: This is a retrospective cohort study of all neonates born at our institution from 1988 through 2010. The medical records of all neonates diagnosed with anemia in the first 24 h of life were reviewed. The incidence of FMH as a documented etiology of anemia was compared between infants born before and after our educational intervention. RESULTS: Of 124,738 births during the study period, 572 neonates with neonatal anemia were identified. A total of 23 cases of FMH demonstrated by positive Kleihauer-Betke testing occurred in our cohort. The incidence of diagnosed FMH prior to our intervention was 22 per 1,000 anemic neonates compared to 182 per 1,000 afterwards (p < 0.001), while the incidence of neonatal anemia remained unchanged (p = 0.377). CONCLUSIONS: FMH may be a significant cause of neonatal anemia. Diagnosis of FMH is highly dependent on physician awareness of the condition. Incorrect or absent diagnosis of the etiology of neonatal anemia has significant implications for our understanding of the epidemiology of FMH.

Alloimmunisation during pregnancy in Greece: need for nationwide HDFN prevention programme.

AIM/OBJECTIVES: To access the incidence and specificity of maternal red blood cells alloimmunisation and its relevant clinical impact in Greece. BACKGROUND: The rate of alloimmunisation in pregnant women in Greece is unknown. MATERIALS/METHODS: We performed a 4-year study in two tertiary hospitals in Greece. Demographics, transfusion and obstetric history were analysed. Maternal alloimmunisation was detected with indirect anti-globulin test. RESULTS: We investigated 4368 pregnant women. Of which 3292 (75·37%) were Greek and 1076 (24·63%) were migrants. In 39 alloimmunised women, 41 alloantibodies were detected (0·89%). The incidence of alloimmunisation was 0·66% (22/3292) in Greeks and 1·76% (17/1076) in migrants (P = 0·01). Anti-D was the most frequent alloantibody (0·18%). Anti-D was more frequent in migrants; 5·76% compared to 0·56% in Greek RhD negative women (P = 0·002). Other antibody specificities in declining frequency rank were anti-K, anti-E, anti-Lea, anti-M, anti-c, anti-Ce, anti-Jka, anti-Jkb and anti-C. Primiparae vs para >2 and past history of blood transfusion were significantly associated with alloimmunisation during pregnancy (P = 0·0088, P < 0·0001, respectively). CONCLUSIONS: Our results depict differences in the delivery of health care between migrants and Greek women, as well as the heterogeneity in practices for the prevention of haemolytic disease of foetus and newborn in Greece and highlight the need for the implementation of nationwide guidelines.

Severe neonatal anemia from fetomaternal hemorrhage: report from a multihospital health-care system.

OBJECTIVE: The incidence of fetomaternal hemorrhage that is severe enough to cause neonatal anemia is not known. Owing to its relative rarity, much of the literature describing this condition is in the form of case reports and small case series. We performed a large, muiticentered, sequential, case series to determine the incidence, antecedents and outcomes. STUDY DESIGN: From the multicentered databases of Intermountain Healthcare, we obtained records of all neonates with hematocrit (Hct) <30% or hemoglobin (Hgb) <10 g dl(-1) on the day of birth, who had Kleihauer-Betke staining or flow cytometric evidence of fetomaternal hemorrhage. RESULT: Among 219,853 live births, 24 had anemia with evidence of fetomaternal hemorrhage (incidence estimate, 1 per 9160 live births). The initial Hgb ranged from 1.4 to 10.2 g dl(-1) (Hct 29.8%). The initial Hgb was <7 g dl(-1) in 18 (67%), <5 g dl(-1) in 12 (50%) and was <3 g dl(-1) in 7 (29%). All 7 mothers in whom neonatal Hgb was <3 g dl(-1) had reported absent fetal movement, as did 13 of 18 mothers when the initial Hgb was <7 g dl(-1). Outcomes were poorer in those with the lowest initial Hgb; in the two lowest, one died on day 1, and the other developed a grade 4 intraventricular hemorrhage (IVH). The adverse outcomes of death, IVH, periventricular leukomalacia, bronchopulmonary dysplasia or hypoxic-ischemic encephalopathy were common; occurring in 71% (17 of the 24), including all with an initial Hgb <5 g dl(-1) and all born at ≤35 weeks of gestation. CONCLUSION: Fetomaternal hemorrhage is a rare but sometimes devastating condition. Those with fetomaternal hemorrhage and an initial Hgb of <5 g dl(-1) are expected to need resuscitation at birth, to receive emergent transfusion support and to be at risk for death and major morbidities. Antenatal suspicion of this diagnosis should occur when absent fetal movement is reported. Improvements in rapid diagnosis are needed to prepare first responders and transfusion services.

Fetomaternal hemorrhage in the second trimester.

AIMS: To investigate fetomaternal hemorrhage (FMH) rate and quantity in the second trimester of pregnancies with fetal anomalies and to assess the impact of invasive prenatal and termination procedures. METHODS: Blood samples from women before termination of pregnancy were collected and analyzed by dual-color flow cytometry. Various clinical parameters were studied for their association with FMH. RESULTS: In total, 67 women were recruited; pre- and post-termination pairs were collected for 31 women. HbF cells were present in 91.0% of specimens, in 29.9% the transfused blood volume was ≥4.2 mL. FMH ≥30 mL was found in 3.0%, and chronic FMH, defined as FMH ≥40% of fetoplacental blood volume in 7.5%. At the limit of quantification (0.1%) none of the clinical parameters was associated with the presence of HbF cells, nor was there a difference in HbF cell concentrations between pre- and post-termination blood samples. CONCLUSIONS: Compared to normal term pregnancy, transfer of fetal red blood cells into the maternal circulation is increased in second-trimester pregnancies with fetal anomalies. FMH is not associated with invasive procedures or surgery performed in the context of termination. We hypothesize that the abnormal pregnancy itself, by means of an abnormal uteroplacental interface, is causing the increased transfer.

Demographics, clinical characteristics and outcomes of neonates diagnosed with fetomaternal haemorrhage.

OBJECTIVE: To determine clinical characteristics, demographics and short-term outcomes of neonates diagnosed with fetomaternal haemorrhage (FMH). DESIGN: The authors analysed the Nationwide Inpatient Sample, 1993 to 2008. Singleton births diagnosed with FMH were identified by International Classification of Diseases (ICD-9) code 762.3. Descriptive, univariate and multivariable regression analyses were performed to determine the national annual incidence of FMH over time as well as demographics and clinical characteristics of neonates with FMH. RESULTS: FMH was identified in 12 116 singleton births. Newborns with FMH required high intensity of care: 26.3% received mechanical ventilation, 22.4% received blood product transfusion and 27.8% underwent central line placement. Preterm birth (OR 3.7), placental abruption (OR 9.8) and umbilical cord anomaly (OR 11.4) were risk factors for FMH. Higher patient income was associated with increased likelihood of FMH diagnosis (OR 1.2), and Whites were more likely to be diagnosed than ethnic minorities (OR 1.9). There was reduced frequency of diagnosis in the Southern USA (OR 0.8 vs the Northeastern USA). CONCLUSIONS: Diagnosis of FMH is associated with significant morbidity as well as regional, socioeconomic and racial disparity. Further study is needed to distinguish between diagnostic coding bias and true epidemiology of the disease. This is the first report of socioeconomic and racial/ethnic disparities in FMH, which may represent disparities in detection that require national attention.

Fetomaternal hemorrhage in normal vaginal delivery and in delivery by cesarean section.

BACKGROUND: The objective was to determine the incidence and volume of fetomaternal hemorrhage (FMH) in normal vaginal delivery and in delivery by cesarean section. Determination of these variables would enable optimalization of guidelines for D alloimmunization prophylaxis. STUDY DESIGN AND METHODS: In a prospective cohort study, a total of 3457 examinations were performed, 2413 after normal vaginal delivery and 1044 after cesarean delivery. FMH was assessed by flow cytometry. (FMH is fetal red blood cell [RBC] volume; fetal blood volume is double [expected fetal hematocrit is 50%].) RESULTS: The fetal RBC volume diagnosed in maternal circulation after delivery ranged from insignificant FMH of not more than 0.1 mL to excessive FMH of 65.9 mL (median, 0.7; mean, 0.78; SD, 1.48). FMH of more than 2.5 mL (immunoglobulin [Ig] G anti-D insufficient dose 50 µg) was observed in 1.4% (49/3457) and excessive volumes of FMH of more than 5 mL (insufficient dose, 100 µg) in 0.29% (10/3457). Delivery by cesarean section presented a higher risk of incidence of FMH of more than 2.5 mL (odds ratio, 2.2; p = 0.004) when compared with normal vaginal delivery. It did not, however, present a significant risk factor for the incidence of excessive volumes of FMH of more than 5 mL. CONCLUSION: During normal vaginal delivery as well as during delivery by cesarean section, FMH of less than 5 mL occurs in the great majority of cases, and thus for the prevention of D alloimmunization, an IgG anti-D dose of 100 µg should be sufficient. Contrarily, only rarely does greater FMH occur and delivery by cesarean section does not present a risk factor.

Maternal red blood cell alloimmunisation in south western Uganda.

AIMS/OBJECTIVES: To identify the frequency and nature of maternal red blood cell (RBC) alloimmunisation in Uganda and to determine the prevalence of RhD negativity and the rate of RBC alloimmunisation in Ugandan pregnant women. BACKGROUND: Haemolytic disease of the foetus and newborn (HDFN) results from maternal alloimmunisation following exposure to allogeneic RBCs during pregnancy or blood transfusion. The prevalence of maternal RBC alloimmunisation in Ugandans is not known. MATERIALS AND METHODS: Pregnant women at Mbarara Hospital, South Western Uganda, were investigated in a cross-sectional study. Demographics, transfusion and obstetric histories were recorded. Maternal RBC alloimmunisation was demonstrated using immunohaematological techniques. RESULTS: A total of 2001 pregnant women were recruited; 3.6% of them being RhD negative. Forty-five women (2.2%; 95% CI: 1.6-2.9) were found to be alloimmunised to RBC antigens. There were 38 RBC alloantibodies of known specificity including anti-S, 12; anti-M, 11; anti-Le(a) , 6; anti-D, 4 and 1 each of anti-K, anti-Fy(b) , anti-Jk(a) , anti-Lu(a) and anti-Kp(a) . In two women (4.4%), there were antibody combinations (anti-M+S and anti-K+Kp(a) ). Obstetric history, gestational age and previous immunising events were not significantly associated with the rate of alloimmunisation. CONCLUSIONS: This study revealed a maternal RBC alloimmunisation rate of 2.2% which was comparable with findings from a Zimbabwean study where the prevalence was 1.7%. Given the 6·0% prevalence of anti-D among RhD-negative women in our study and the high immunogenicity of the D antigen, programmes for preventing anti-D alloimmunisation and HDFN in Uganda should be considered seriously.

Fetomaternal hemorrhage in women undergoing elective cesarean section.

OBJECTIVE: To investigate the degree of fetomaternal hemorrhage (FMH) caused by elective cesarean section. DESIGN: Descriptive study. SETTINGS: University Hospitals in Copenhagen, Denmark. POPULATION: Women scheduled for elective cesarean section, in the period September 2007 to January 2009, at the Department of Gynecology and Obstetrics, Hvidovre Hospital, University of Copenhagen, Denmark. METHODS: Two maternal blood samples were taken, the first before cesarean section and the second immediately after. Both samples were analyzed at the Blood Bank, Rigshospitalet, Copenhagen, for the presence of fetal red blood cells (fRBCs) using flow cytometry. FMH associated with cesarean section was defined as the difference between the volumes of fRBCs in the two samples. MAIN OUTCOME MEASURES: The frequency and volume of FMH caused by elective cesarean section. RESULTS: 207 women were included in the study. FMH was detected in 38 cases (18.4%). Of these, 22 women (10.6%) had FMH of less than 1 ml fRBCs, 13 women (6.3%) had FMH between 1 and 4 ml fRBCs, and three women (1.4%) had FMH above 4 ml fRBCs. CONCLUSIONS: We found no evidence for recommending general screening for FMH in connection with elective cesarean section, provided guidelines such as the current Danish guidelines for Rhesus prophylaxis are followed.

Fetomaternal transfusion after amniocentesis and cordocentesis.

OBJECTIVE: To compare the extent of fetomaternal transfusion after amniocentesis and cordocentesis. SETTING: Three-hundred and forty-five amniocentesis and 268 cordocentesis were performed for genetic indications. The extent of fetomaternal transfusion was calculated on the basis of the maternal serum alpha-fetoprotein level changes. RESULTS: The mean fetomaternal transfusion was 6.3 and 62 µL in the amniocentesis and cordocentesis groups, respectively. Transplacental needle passage and longer procedural time were risk factors for fetomaternal transfusion. The frequency of transplacental passage was higher and the procedural time was longer in the cordocentesis group. The fetal loss rate was 1.17% after amniocentesis and 1.2% after cordocentesis, respectively. CONCLUSIONS: Cordocentesis causes more injury to the extrafetal compartment, which results in a higher level of fetomaternal transfusion. However, though a nearly ten times higher fetomaternal transfusion was observed after cordocentesis, there was no essential difference in pregnancy outcome between the two groups.