Prevention of Rh alloimmunization: are we there yet?

National variation in guidance for the management of pregnant women presenting with major trauma

INTRODUCTION

The initial assessment of pregnant women presenting with significant injuries is more complicated than that of non-pregnant women because of physiological and anatomical changes, and the presence of the fetus. The aim of this study was to determine whether guidelines for the early management of severely injured pregnant women exist, which aspects of assessment/management they cover and to what extent there is national consistency.

METHODS

A freedom of information request was submitted to 125 acute National Health Service trusts in England and six in Wales. The trusts were asked to confirm whether they have a guideline for the management of major trauma in pregnant women presenting to the emergency department and what the guidelines were.

RESULTS

In total, 96.2% of trusts responded, of which 19% have a specific guideline and 7.9% have a generic guideline for assessing pregnant women in the emergency department, irrespective of injury severity. Of the responding trusts, 19.8% have a protocol that specifies when an obstetric trauma call should be put out by the emergency department and when a pregnant woman should be transferred to a major trauma centre for definitive management. Our results found that 69.8% routinely call obstetrics or gynaecology to the trauma call compared with 36.5% calling paediatrics.

CONCLUSIONS

The heterogeneity evident across trusts necessitates the establishment of national guidelines for the assessment of pregnant women with major trauma to standardise communication and delivery of care.

Trauma in Pregnancy

Trauma in pregnancy can range from a mild injury, such as a fall from standing height, to a major injury, involving a penetrating injury or a high force motor vehicle collision. Providing care to a pregnant patient with trauma presents a unique challenge as 2 patients are at risk for complications, that is, the mother and the fetus, both of whom require evaluation and management. Health care professionals should be aware of and be prepared to manage complications of trauma in pregnancy, given its significant associated morbidity and mortality. This article details the epidemiology, etiology, assessment, diagnosis, and management of trauma in pregnancy.

Noninvasive Fetal RhD Blood Group Genotyping: A Systematic Review of Economic Evaluations

OBJECTIVE

Noninvasive fetal rhesus D (RhD) blood group genotyping may prevent unnecessary use of anti-D immunoglobulin (RhIG) in non-alloimmunized RhD-negative pregnancies and can guide management of alloimmunized pregnancies. We conducted a systematic review of the economic literature to determine the cost-effectiveness of this intervention over usual care.

DATA SOURCES

Systematic literature searches of bibliographic databases (Ovid MEDLINE, Embase, and Cochrane) until February 26, 2019, and auto-alerts until October 30, 2020, and of grey literature sources were performed to retrieve all English-language studies.

STUDY SELECTION

We included studies done in serologically confirmed non-alloimmunized or alloimmunized RhD-negative pregnancies, comparing costs and effectiveness of the intervention versus usual care.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted data from the eligible studies and assessed their methodological quality (risk of bias) using the Quality of Health Economic Studies (QHES) and Drummond tools. We narratively synthesized findings. Our review included 8 economic studies that evaluated non-invasive fetal RhD genotyping followed by targeted RhIG prophylaxis in non-alloimmunized pregnancies. Five studies further considered a subsequent alloimmunized pregnancy. The cost-effectiveness of the intervention versus usual care (e.g., universal RhIG or prophylaxis conditional on results of paternal testing) for non-alloiummunized pregnancies was inconsistent. Two studies indicated greater benefits and lower costs for the intervention, and another 2 suggested a trade-off. In 4 studies, the intervention was less effective and costlier than alternatives. Three studies were determined to be of high quality by both tools. Two of these studies favoured the intervention, and one assessed benefits in quality-adjusted life-years. No study clearly examined the cost-effectiveness of repetitive use of fetal genotyping in multiple non-alloimmunized or alloimmunized pregnancies. The cost of genotyping was the most influential parameter.

CONCLUSION

The cost-effectiveness of noninvasive fetal RhD genotyping for non-alloimmunized pregnancies varies between studies. Potential savings from targeted management of alloimmunized pregnancies requires further research.

Infants affected by Rh sensitization: A 2-year Canadian National Surveillance Study

INTRODUCTION

Rh sensitization occurs when Rh(D)-negative women develop anti-Rh(D) antibodies following exposure through pregnancy or transfusion. Rh disease may cause jaundice, anemia, neurological impairment, and death. It is rare in countries where Rh Immune Globulin (RhIg) is used. Canadian Rh sensitization and disease rates are unknown.

METHODS

This survey-based study was conducted using a Canadian Paediatric Surveillance Program questionnaire sent to Canadian paediatricians and paediatric subspecialists to solicit Rh disease cases from May 2016 to June 2018. Paediatricians reported Rh-positive infants ≤ 60 days of age, born to Rh-negative mothers with RhD sensitization.

RESULTS

Sixty-two confirmed cases of infants affected by Rh(D) sensitization were reported across Canada. The median gestational age of neonates was term, age at presentation was 2 hours, and hemoglobin at presentation was 137.5 g/L (33 to 203 g/L). The median peak bilirubin and phototherapy duration were 280 µmol/L (92 to 771 µmol/L), and 124 hours, respectively. Thirty (48%) infants received Intravenous immune globulin (IVIG) (median two doses). Seventeen (27%) received one to three simple transfusions; 10 (16%) required exchange transfusions. Six (10%) infants presented with acute bilirubin encephalopathy, and less than five presented with seizures. Fourteen mothers with affected infants were born outside of Canada.

DISCUSSION

Rh disease continues to exist in Canada. Additional efforts are needed to raise awareness of Rh disease, prevent disease, and minimize sequelae when it does occur. The ongoing global burden of Rh Disease, as well as the possibility of emerging Rh immunoglobulin refusal are among factors that could be taken into consideration in future prevention efforts.

Red cell alloimmunization: A 2020 update

Management of maternal red cell alloimmunization has been revolutionized over the last 60 years. Advances in the prevention, screening, diagnosis, and treatment of alloimmune-induced fetal anemia make this condition an exemplar for contemporary practice in fetal therapy. Since survival is now an expectation, attention has turned to optimization of long-term outcomes following an alloimmunized pregnancy. In this review, the current management of red cell alloimmunization is described. Current research and future directions are discussed with particular emphasis on later life outcomes after alloimmune fetal anemia.

Rural healthcare delivery: Navigating a complex ecosystem

Clinical Practice Guidelines (CPGs) provide evidence-based recommendations for Healthcare Providers (HCPs) to utilize when making patient care decisions. Rural providers face challenges in the provision of evidence-based care, including the use of guidelines. The aim of this article is to explore the complexities of providing healthcare in rural areas. This article will focus on a specific aspect of rural maternity care with well-established CPGs, the prevention of Rhesus D factor alloimmunization. An applied health research approach, interpretive description, utilized semistructured interviews with HCPs across the vast geographic region of northern British Columbia. The study found that HCPs are aware of guidelines but face various barriers during implementation. In order to implement guidelines within practice, rural HCPs adapt processes to overcome local barriers. These process adaptations need to be identified and shared across a large health authority with a complex geography and healthcare system to ensure quality of care.

Very Prolonged Anti-D: Confusion Surrounding Alloimmunization After Extra Rh Immunoglobulin: A Case Report

BACKGROUND

Rh immunoglobulin (RhIg) is usually detectable a maximum of 12 to 14 weeks after administration. Positive antibodies beyond this time frame suggests alloimmunization.

CASE

A woman had three pregnancies over a 6-month period, with two first-trimester losses. She received RhIg in the first pregnancy but not in the second. Two months after the second loss, in her third pregnancy, she received RhIg at week 6 due to first-trimester bleeding. She was subsequently anti-D antibody positive up to week 28 with antibodies too low to titre, leading to confusion about whether alloimmunization had occurred.

CONCLUSION

Rh Ig administration led to positive anti-D antibodies lasting 22 weeks, suggesting keeping this differential diagnosis in mind when suspecting alloimmunization with positive antibodies at levels too low to titre.

Rhesus disease: a global prevention strategy

After nearly five decades of effective prophylaxis in high-income countries, the incidence of rhesus haemolytic disease (also known as haemolytic disease of the fetus and newborn) has substantially decreased, and as a result, clinical experience of the disease among health-care providers is insufficient. By contrast, a worldwide study found that rhesus haemolytic disease continues to be a public health problem in low-income and middle-income countries, affecting annually in more than 150 000 children, and causing thousands of stillbirths, neonatal deaths, and cases of hyperbilirubinaemia with its sequelae (kernicterus and bilirubin-induced neurological dysfunction). Solutions to this problem will require the combined and integrated effort of physicians and other health-care workers, international agencies, manufacturers of the prophylactic agent (rhesus immunoglobulin), health policy makers, and governments of low-income and middle-income countries.

Risk factors for fetomaternal bleeding after laser therapy for twin-twin transfusion syndrome

OBJECTIVE

To quantify and assess potential risk factors for transplacental passage of fetal red blood cells (RBCs) into the maternal circulation (fetomaternal bleeding, FMB) after laser surgery for twin-twin transfusion syndrome (TTTS).

STUDY DESIGN

A retrospective study of Rhesus-D negative patients that underwent laser surgery for TTTS. Patients with and without postoperative detectable fetal RBCs on Kleihauer-Betke (KB) testing were compared to determine risk factors for FMB. Patients were further sub-classified into those with a FMB < 20% and ≥20% of estimated fetoplacental blood volume.

RESULTS

Of 60 studied patients, 26/60 (43%) had a positive postoperative KB test. The median fetal:adult RBC ratio was 0.00125, estimated to be a FMB volume of 6.25 mL. There were 17/26 (65%) of patients with FMB < 20% and 9/26 (35%) patients with ≥20% of the fetoplacental blood volume. Stage III-Recipient and III-Recipient/Donor patients were more likely to have a positive KB test (14/21 [66.7%] vs 12/39 [30.8%], OR = 4.50 [1.27-16.54], P = 0.0162). No other risk factors for FMB were apparent.

CONCLUSIONS

Fetomaternal bleed appears to be a common finding after laser surgery for TTTS. TTTS Stage, particularly stage III-Recipient and III-Recipient/Donor, appears to be a risk factor for FMB.

External cephalic version for breech presentation at term

BACKGROUND

Management of breech presentation is controversial, particularly in regard to manipulation of the position of the fetus by external cephalic version (ECV). ECV may reduce the number of breech presentations and caesarean sections, but there also have been reports of complications with the procedure.

OBJECTIVES

The objective of this review was to assess the effects of ECV at or near term on measures of pregnancy outcome. Methods of facilitating ECV, and ECV before term are reviewed separately.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Register (28 February 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of ECV at or near term (with or without tocolysis) compared with no attempt at ECV in women with breech presentation.

DATA COLLECTION AND ANALYSIS

Two review authors assessed eligibility and trial quality, and extracted the data.

MAIN RESULTS

We included eight studies, with a total of 1308 women randomised. The pooled data from these studies show a statistically significant and clinically meaningful reduction in non-cephalic presentation at birth (average risk ratio (RR) 0.42, 95% confidence interval (CI) 0.29 to 0.61, eight trials, 1305 women); vaginal cephalic birth not achieved (average RR 0.46, 95% CI 0.33 to 0.62, seven trials, 1253 women, evidence graded very low); and caesarean section (average RR 0.57, 95% CI 0.40 to 0.82, eight trials, 1305 women, evidence graded very low) when ECV was attempted in comparison to no ECV attempted. There were no significant differences in the incidence of Apgar score ratings below seven at one minute (average RR 0.67, 95% CI 0.32 to 1.37, three trials, 168 infants) or five minutes (RR 0.63, 95% CI 0.29 to 1.36, five trials, 428 infants, evidence graded very low), low umbilical vein pH levels (RR 0.65, 95% CI 0.17 to 2.44, one trial, 52 infants, evidence graded very low), neonatal admission (RR 0.80, 95% CI 0.48 to 1.34, four trials, 368 infants, evidence graded very low), perinatal death (RR 0.39, 95% CI 0.09 to 1.64, eight trials, 1305 infants, evidence graded low), nor time from enrolment to delivery (mean difference -0.25 days, 95% CI -2.81 to 2.31, two trials, 256 women).All of the trials included in this review had design limitations, and the level of evidence was graded low or very low. No studies attempted to blind the intervention, and the process of random allocation was suboptimal in several studies. Three of the eight trials had serious design limitations, however excluding these studies in a sensitivity analysis for outcomes with substantial heterogeneity did not alter the results.

AUTHORS' CONCLUSIONS

Attempting cephalic version at term reduces the chance of non-cephalic presentation at birth, vaginal cephalic birth not achieved and caesarean section. There is not enough evidence from randomised trials to assess complications of ECV at term. Large observational studies suggest that complications are rare.

Costs and benefits of non-invasive fetal RhD determination

OBJECTIVE

Non-invasive fetal Rhesus (Rh) D genotyping, using cell-free fetal DNA (cffDNA) in the maternal blood, allows targeted antenatal anti-RhD prophylaxis in unsensitized RhD-negative pregnant women. The purpose of this study was to determine the cost and benefit of this approach as compared to routine antenatal anti-RhD prophylaxis for all unsensitized RhD-negative pregnant women, as is the current policy in the province of Alberta, Canada.

METHODS

This study was a decision analysis based on a theoretical population representing the total number of pregnancies in Alberta over a 1-year period (n = 69 286). A decision tree was created that outlined targeted prophylaxis for unsensitized RhD-negative pregnant women screened for cffDNA (targeted group) vs routine prophylaxis for all unsensitized RhD-negative pregnant women (routine group). Probabilities at each decision point and costs associated with each resource were calculated from local clinical and administrative data. Outcomes measured were cost, number of women sensitized and doses of Rh immunoglobulin (RhIG) administered.

RESULTS

The estimated cost per pregnancy for the routine group was 71.43 compared with 67.20 Canadian dollars in the targeted group. The sensitization rates per RhD-negative pregnancy were equal, at 0.0012, for the current and targeted programs. Implementing targeted antenatal anti-RhD prophylaxis would save 4072 doses (20.1%) of RhIG over a 1-year period in Alberta when compared to the current program.

CONCLUSIONS

These data support the feasibility of a targeted antenatal anti-RhD prophylaxis program, at a lower cost than that of the existing routine prophylaxis program, with no increased risk of sensitization.

External cephalic version for breech presentation at term

BACKGROUND

Management of breech presentation is controversial, particularly in regard to manipulation of the position of the fetus by external cephalic version (ECV). ECV may reduce the number of breech presentations and caesarean sections, but there also have been reports of complications with the procedure.

OBJECTIVES

The objective of this review was to assess the effects of ECV at or near term on measures of pregnancy outcome. Methods of facilitating ECV, and ECV before term are reviewed separately.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Register (7 August 2012).

SELECTION CRITERIA

Randomised trials of ECV at or near term (with or without tocolysis) compared with no attempt at ECV in women with breech presentation.

DATA COLLECTION AND ANALYSIS

Two review authors assessed eligibility and trial quality, and extracted the data.

MAIN RESULTS

We included seven studies. The pooled data from these studies show a statistically significant and clinically meaningful reduction in non-cephalic birth (seven trials, 1245 women; risk ratio (RR) 0.46, 95% confidence interval (CI) 0.31 to 0.66; and caesarean section (seven trials, 1245 women; RR 0.63, 95% CI 0.44 to 0.90) when ECV was attempted. There were no significant differences in the incidence of Apgar score ratings below seven at one minute (two trials, 108 women; RR 0.95, 95% CI 0.47 to 1.89) or five minutes (four trials, 368 women; RR 0.76, 95% CI 0.32 to 1.77), low umbilical artery pH levels (one trial, 52 women; RR 0.65, 95% CI 0.17 to 2.44), neonatal admission (one trial, 52 women; RR 0.36, 95% CI 0.04 to 3.24), perinatal death (six trials, 1053 women; RR 0.34, 95% CI 0.05 to 2.12), nor time from enrolment to delivery (2 trials, 256 women; weighted mean difference -0.25 days, 95% CI -2.81 to 2.31).

AUTHORS' CONCLUSIONS

Attempting cephalic version at term reduces the chance of non-cephalic births and caesarean section. There is not enough evidence from randomised trials to assess complications of external cephalic version at term. Large observational studies suggest that complications are rare.

Biochemistry testing associated with pregnancy and the newborn period -- a lot has changed since you were a baby!

Everyone has been a newborn, and everyone's mother has been pregnant. Despite the commonality of these events, medical care and the clinical chemistry laboratory's role in it have changed remarkably over the last 50 years. This review is a historical overview of clinical chemistry testing that is related to pregnancy and the newborn period.

Prevention and management of RhD isoimmunization

An Rh-negative woman is at risk for developing Rh isoimmunization upon exposure to RhD antigens from her Rh-positive baby through fetal-maternal hemorrhage. The incidence of Rh isoimmunization and fetal hemolytic disease has decreased substantially since Rh immune globulin was introduced in 1968. When RhD sensitization does occur, careful follow-up of these mothers and judicious intervention can result in good outcomes for most pregnancies. Both Doppler assessment of middle cerebral artery peak systolic velocity and spectral analysis of amniotic fluid at 450 nm (DeltaOD 450) are useful in the diagnosis and management of fetal anemia.