Clinical OpinionIs Rh immune globulin needed in early first-trimester abortion? A review☆
Section snippets
Evidence supporting Rh immune globulin in early-trimester abortions
Fetal-maternal transfusion has been demonstrated as early as 5 to 6 weeks of gestation. The mean volume of fetal-maternal transfusion at 8 weeks has been calculated to be 0.33 mL.2 No recent studies have looked at whether those fetal red blood cells (RBC) express the Rh(D) antigen; however, Bergstrom et al12 demonstrated that fetal RBCs can express the Rh(D) antigen as early as 38 days from conception, or 52 days from last menstrual period. The amount of fetal blood needed to cause
Evidence against Rh immune globulin in early-trimester abortions
A weakness of the evidence supporting the use of Rh immune globulin in the first trimester is its reliance on studies that evaluated fetomaternal hemorrhage (positive KB test) and not the actual development of Rh(D) antibodies. Thus, the true incidence of the development of Rh(D) antibodies in an abnormal first-trimester pregnancy or after elective termination is difficult to determine and remains unknown. A second severe limitation is that many of these studies have no control population or
Critique of the data
The data available to make an evidence-based recommendation regarding the utility of Rh immune globulin in the first trimester are extremely limited. Most studies were performed in the early 1970s and were not controlled. In aggregate, these data demonstrate that the number of cases of Rh-negative women who become isoimmunized after pregnancy complications or terminations in the first trimester is very low. The incidence of isoimmunization after a first-trimester abortion ranged from 0% to 3%.
Clinical recommendations
Although the evidence to support the use of Rh immune globulin in the first trimester is sparse, there is theoretic evidence of its necessity. Although calculations of the amount of blood necessary to result in immunosensitization are problematic, they do suggest that fetal-maternal hemorrhage in the first trimester is of sufficient volume to potentially cause immunosensitization. Moreover, there have been cases of immunosensitization reported with first-trimester abortions, although the actual
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Do Rh-negative women with an early spontaneous abortion need Rh immune prophylaxis?
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A case of Rh isoimmunization: should threatened first-trimester abortion be an indication for Rh immune globulin prophylaxis?
Am J Obstet Gynecol
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Am J Obstet Gynecol
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The transplacental passage of fetal red blood cells and the pathogenesis of Rh immunization during pregnancy
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Rise in maternal serum α-fetoprotein concentration after chorionic villus sampling and the possibility of isoimmunization
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Cited by (33)
Prevention of Rhesus-D Alloimmunization in the First Trimester of Pregnancy: Economic Analysis of Three Management Strategies
2024, Transfusion Medicine Reviews“Provoked” feto-maternal hemorrhage may represent insensible cell exchange in pregnancies from 6 to 22 weeks gestational age
2019, ContraceptionCitation Excerpt :Moreover, the characterization of early antigenic expression and thus the immunologic significance of fetal red blood cells has also been limited [11–13]. Regardless, it is common for some small volume of fetal cells to enter the maternal circulation during normal pregnancy [14–16]. Given the uncertainty surrounding risk for sensitization across gestational ages and risk events, the American College of Obstetricians and Gynecologists (ACOG) recommends consideration of treatment for all Rh-negative women with vaginal bleeding, first-trimester miscarriage, amniocentesis, CVS, and ectopic pregnancy at any point in gestation [17].
Complications in Early Pregnancy
2019, Emergency Medicine Clinics of North America
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Reprint requests: Kurt T. Barnhart, MD, MSCE, Department of Obstetrics and Gynecology, University of Pennsylvania Medical Center, 3400 Spruce St, Dulles 106, Philadelphia, PA 19104. E-mail: [email protected]