Anti-D administration after spontaneous miscarriage for preventing Rhesus alloimmunisation

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.

Society of Family Planning committee consensus on Rh testing in early pregnancy

Historical evidence that fetal red blood cell (RBC) exposure during early spontaneous or induced abortion can cause maternal Rh sensitization is limited. A close reading of these studies indicates that forgoing Rh immunoglobulin administration before 12-weeks gestation is highly unlikely to increase risk of Rh (D) antibody development, and recent studies indicate that fetal RBC exposure during aspiration abortion <12 weeks gestation is below the calculated threshold to cause maternal Rh sensitization, and the amount of fetomaternal hemorrhage during dilation and evacuation procedures up to 18-weeks gestation is adequately treated with 100-mcg of Rh immunoglobulin. We provide updated recommendations for Rh immunoglobulin administration based on this new evidence.

Rhesus isoimmunisation in unsensitised RhD-negative individuals seeking abortion at less than 12 weeks' gestation: a systematic review

AIM

The aim of this review was to systematically review the outcome of routine anti-D administration among unsensitised rhesus (RhD)-negative individuals who have an abortion. This review is registered with Prospero.

METHODS

A search for all published and ongoing studies, without restrictions on language or publication status, was performed using the following databases from their inception: EBM Reviews Ovid - Cochrane Central Register of Controlled Trials, MEDLINE Ovid (Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily), Embase.com, Popline and Google Scholar. Study types included: randomised controlled trials, controlled trials, cohort and case-control studies from 1971 onwards. The population included women who undergo an abortion (induced, incomplete, spontaneous or septic abortion), medical or surgical <12 weeks, and isoimmunisation in a subsequent pregnancy. The primary outcomes were: (1) development of a positive Kleihauer-Betke test and (2) development of Rh alloimmunisation in a subsequent pregnancy.

RESULTS

A total of 2652 studies were screened with 105 accessed for full-text review. Two studies have been included with high bias appreciated. Both studies found few women to be sensitised in forming antibodies after an abortion. The limited studies available and heterogeneity prevent the conduction of a meta-analysis.

CONCLUSIONS

Rh immunoglobulin has well-documented safety. However, it is not without risks and costs, is a possible barrier to delivering efficient services, and may have limited availability in some countries. The evidence base and quality of studies are currently limited. There is unclear benefit from the recommendation for Rh testing and immunoglobulin administration in early pregnancy. More research is needed as clinical practice guidelines are varied, based on expert opinions and moving away from testing and administration at time of abortion.

IMPLICATIONS

There is limited evidence surrounding medical benefit of Rh testing and immunoglobulin administration in early pregnancy. Further research is needed to define alloimmunisation and immunoglobulin benefit to update standards of care. Additionally, other factors should be considered in forming clinical policies and guidelines such as costs, feasibility and impact on access to care for patients.

Evaluation of Stillbirth Among Pregnant People With Sickle Cell Trait

IMPORTANCE

Relative to what is known about pregnancy complications and sickle cell disease (SCD), little is known about the risk of pregnancy complications among those with sickle cell trait (SCT). There is a lack of clinical research among sickle cell carriers largely due to low sample sizes and disparities in research funding.

OBJECTIVE

To evaluate whether there is an association between SCT and a stillbirth outcome.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included data on deliveries occurring between January 1, 2010, and August 15, 2017, at 4 quaternary academic medical centers within the Penn Medicine health system in Pennsylvania. The population included a total of 2482 deliveries from 1904 patients with SCT but not SCD, and 215 deliveries from 164 patients with SCD. Data were analyzed from May 3, 2019, to September 16, 2021.

EXPOSURES

The primary exposure of interest was SCT, identified using clinical diagnosis codes recorded in the electronic health record.

MAIN OUTCOMES AND MEASURES

A multivariate logistic regression model was constructed to assess the risk of stillbirth using the following risk factors: SCD, numbers of pain crises and blood transfusions before delivery, delivery episode (as a proxy for parity), prior cesarean delivery, multiple gestation, patient age, marital status, race and ethnicity, ABO blood type, Rhesus (Rh) factor, and year of delivery.

RESULTS

This cohort study included 50 560 patients (63 334 deliveries), most of whom were aged 25 to 34 years (29 387 of 50 560 [58.1%]; mean [SD] age, 29.5 [6.1] years), were single at the time of delivery (28 186 [55.8%]), were Black or African American (23 777 [47.0%]), had ABO blood type O (22 879 [45.2%]), and were Rhesus factor positive (44 000 [87.0%]). From this general population, 2068 patients (4.1%) with a sickle cell gene variation were identified: 1904 patients (92.1%) with SCT (2482 deliveries) and 164 patients (7.9%) with SCD (215 deliveries). In the fully adjusted model, SCT was associated with an increased risk of stillbirth (adjusted odds ratio [aOR], 8.94; 95% CI, 1.05-75.79; P = .045) while adjusting for the risk factors of SCD (aOR, 26.40; 95% CI, 2.48-280.90; P = .007) and multiple gestation (aOR, 4.68; 95% CI, 3.48-6.29; P < .001).

CONCLUSIONS AND RELEVANCE

The results of this large, retrospective cohort study indicate an increased risk of stillbirth among pregnant people with SCT. These findings underscore the need for additional risk assessment during pregnancy for sickle cell carriers.

Fetal-Maternal Hemorrhage in First-Trimester Intrauterine Hematoma

OBJECTIVE

The objective of this study was to compare the frequency and percentage of fetal hemoglobin (HbF%) by flow cytometry of (1) first-trimester asymptomatic patients with intrauterine hematoma (IUH), (2) first-trimester pregnant patients with vaginal bleeding (VB), and (3) first-trimester asymptomatic pregnant women without hematoma.

METHODS

Prospective study involving pregnant women in the first trimester of pregnancy. Patients with ultrasound findings of asymptomatic hematoma and with VB were paired with asymptomatic pregnant women of same gestational age without hematoma (control group [CG]). Maternal blood HbF% was evaluated by flow cytometry. The groups were compared in terms of circulating fetal hemoglobin and HbF%.

RESULTS

Sixty-six patients were selected, 22 with hematoma, 17 with bleeding, and 27 in the CG. Fetal hemoglobin was detected in 15 patients with hematoma (68.2%) and 13 with bleeding (76.5%) and in 20 of the control (74.1%) (p = 0.830). The mean HbF% of each group was 0.054, 0.012, and 0.042 for hematoma, bleeding, and control, respectively, and differences were not significant (p = 0.141). There was a moderate negative correlation between the volume of hematoma and HbF% (rSpearman = -0.527; p = 0.012).

CONCLUSIONS

The fetal-maternal hemorrhage expressed by Hbf% in first-trimester pregnancies did not seem to differ between patients with and without ultrasound findings of IUH.

Antenatal and postpartum prevention of Rh alloimmunization: A systematic review and GRADE analysis

BACKGROUND

Existing systematic reviews of Rh immunoprophylaxis include only data from randomized controlled trials, have dated searches, and some do not report on all domains of risk of bias or evaluate the certainty of the evidence. Our objective was to perform an updated review, by including new trials, any comparative observational studies, and assessing the certainty of the evidence using the GRADE framework.

METHODS

We searched MEDLINE, Embase and the Cochrane Library from 2000 to November 26, 2019. Relevant websites and bibliographies of systematic reviews and guidelines were searched for studies published before 2000. Outcomes of interest were sensitization and adverse events. Risk of bias was evaluated with the Cochrane tool and ROBINS-I. The certainty of the evidence was performed using the GRADE framework.

RESULTS

Thirteen randomized trials and eight comparative cohort studies were identified, evaluating 12 comparisons. Although there is some evidence of beneficial treatment effects (e.g., at 6-months postpartum, fewer women who received RhIg at delivery compared to no RhIg became sensitized [70 fewer sensitized women per 1,000 (95%CI: 67 to 71 fewer); I2 = 73%]), due to very low certainty of the evidence, the magnitude of the treatment effect may be overestimated. The certainty of the evidence was very low for most outcomes often due to high risk of bias (e.g., randomization method, allocation concealment, selective reporting) and imprecision (i.e., few events and small sample sizes). There is limited evidence on prophylaxis for invasive fetal procedures (e.g. amniocentesis) in the comparative literature, and few studies reported adverse events.

CONCLUSION

Serious risk of bias and low to very low certainty of the evidence is found in existing RCTs and comparative observational studies addressing optimal effectiveness of Rh immunoprophylaxis. Guideline development committees should exercise caution when assessing the strength of the recommendations that inform and influence clinical practice in this area.

Medication Abortion Up to 70 Days of Gestation

Medication abortion, also referred to as medical abortion, is a safe and effective method of providing abortion. Medication abortion involves the use of medicines rather than uterine aspiration to induce an abortion. The U.S. Food and Drug Administration (FDA)-approved medication abortion regimen includes mifepristone and misoprostol. The purpose of this document is to provide updated evidence-based guidance on the provision of medication abortion up to 70 days (or 10 weeks) of gestation. Information about medication abortion after 70 days of gestation is provided in other ACOG publications [1].

The concentration of fetal red blood cells in first-trimester pregnant women undergoing uterine aspiration is below the calculated threshold for Rh sensitization

OBJECTIVES

To calculate the minimum fetal red blood cell concentration required to cause maternal Rh sensitization; validate the use of a flow cytometry protocol below that concentration; preliminarily assess the concentrations of fetal red blood cells in pregnant women before and after uterine aspiration.

STUDY DESIGN

Using pre-existing literature, we calculated the lowest concentration of fetal red blood cells found to cause sensitization within adult female circulation. We validated a two-color flow cytometry protocol using fluorescently labeled antibodies to Hemoglobin F (expressed by fetal red blood cells and adult F cells) and Carbonic Anhydrase (expressed in red blood cells during the third trimester and postnatally) by titrating second trimester cord blood into non-pregnant adult blood. We applied this flow cytometry protocol in a prospective cohort study of 42 pregnant women at 5-12 weeks gestational age undergoing uterine aspiration for induced or spontaneous abortion.

RESULTS

The calculated threshold for causing Rh sensitization was 250 fetal red blood cells per 10 million total red blood cells. We showed a linear relationship between observed and expected fetal red blood cell fractions in titrated samples. Fetal red blood cell counts were more reliable when samples acquired by flow cytometry contained at least 1 million red blood cells. All 37 subjects with evaluable paired samples demonstrated fetal red blood cell concentrations below the calculated threshold for Rh sensitization both pre- and post-procedure. The fetal RBC concentrations increased from a mean of 4.5 (median 0, range 0-57) fetal RBCS pre- to a mean of 8.6 (median 2, range 0-32) fetal RBCs post- per 10 million total RBCs (p < 0.001).

CONCLUSIONS

Flow cytometry was capable of separately quantifying fetal red blood cells and maternal F cells to very dilute concentrations. Fetal red blood cell exposure in the first trimester was well below the calculated threshold for maternal Rh sensitization in our cohort. Larger studies are warranted to confirm our pilot study findings, fill this evidence gap and inform universal guidelines for administering Rh immunoglobulin after first trimester uterine aspiration.

IMPLICATIONS

Fetal red blood cell exposure following first trimester uterine aspiration is well below the calculated threshold for maternal Rh sensitization in our cohort.

Red Blood Cell Alloimmunization in the Pregnant Patient

Alloimmunization to red blood cell (RBC) antigens represents a challenge for physicians caring for women of child bearing potential. Exposure to non-self RBC antigens may occur during transfusion or pregnancy leading to the development of antibodies. If a subsequent fetus bears that antigen, maternal antibodies may attack the fetal red blood cells causing red cell destruction and clinically significant hemolytic disease of the fetus and newborn (HDFN). In the most severe cases, HDFN may result in intrauterine fetal demise due to high output cardiac failure, effusions and ascites, known as "hydrops fetalis". This article reviews strategies for management and prevention of RBC alloimmunization in women of child bearing potential.

Can available interventions end preventable deaths in mothers, newborn babies, and stillbirths, and at what cost?

Progress in newborn survival has been slow, and even more so for reductions in stillbirths. To meet Every Newborn targets of ten or fewer neonatal deaths and ten or fewer stillbirths per 1000 births in every country by 2035 will necessitate accelerated scale-up of the most effective care targeting major causes of newborn deaths. We have systematically reviewed interventions across the continuum of care and various delivery platforms, and then modelled the effect and cost of scale-up in the 75 high-burden Countdown countries. Closure of the quality gap through the provision of effective care for all women and newborn babies delivering in facilities could prevent an estimated 113,000 maternal deaths, 531,000 stillbirths, and 1·325 million neonatal deaths annually by 2020 at an estimated running cost of US$4·5 billion per year (US$0·9 per person). Increased coverage and quality of preconception, antenatal, intrapartum, and postnatal interventions by 2025 could avert 71% of neonatal deaths (1·9 million [range 1·6-2·1 million]), 33% of stillbirths (0·82 million [0·60-0·93 million]), and 54% of maternal deaths (0·16 million [0·14-0·17 million]) per year. These reductions can be achieved at an annual incremental running cost of US$5·65 billion (US$1·15 per person), which amounts to US$1928 for each life saved, including stillbirths, neonatal, and maternal deaths. Most (82%) of this effect is attributable to facility-based care which, although more expensive than community-based strategies, improves the likelihood of survival. Most of the running costs are also for facility-based care (US$3·66 billion or 64%), even without the cost of new hospitals and country-specific capital inputs being factored in. The maximum effect on neonatal deaths is through interventions delivered during labour and birth, including for obstetric complications (41%), followed by care of small and ill newborn babies (30%). To meet the unmet need for family planning with modern contraceptives would be synergistic, and would contribute to around a halving of births and therefore deaths. Our analysis also indicates that available interventions can reduce the three most common cause of neonatal mortality--preterm, intrapartum, and infection-related deaths--by 58%, 79%, and 84%, respectively.