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MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Antibody Screen Positive: Rh Disease and Other Atypical Antibodies
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14. Rh Disease and Other Atypical Antibodies
Step 14. ACOG Resources
Prevention of Rh D Alloimmunization (ACOG Practice Bulletin no. 4, May 1999)
Summary of Recommendations
The reduction in the incidence of Rh D alloimmunization is a prototype for the effectiveness of preventive medicine. Some controversies remain, however, such as the use of anti-D immune globulin in patients with either threatened abortion or antenatal hemorrhage. Similarly, it may not be cost-effective either to screen all Rh D-negative patients with an indirect Coombs test at 24-28 weeks of gestation or to screen all postpartum patients for excessive fetomaternal hemorrhage.
The following recommendations are based on good and consistent scientific evidence (Level A):
The Rh D-negative woman who is not Rh D-alloimmunized should receive anti-D immune globulin:
- At approximately 28 weeks of gestation, unless the father of the baby is also known to be Rh D negative
- Within 72 hours after the delivery of an Rh D-positive infant
- After a first-trimester pregnancy loss
- After invasive procedures, such as chorionic villus sampling, amniocentesis, or fetal blood sampling
The following recommendations are based primarily on consensus and expert opinion (Level C):
Anti-D immune globulin prophylaxis should be considered if the patient has experienced:
- Threatened abortion
- Second- or third-trimester antenatal bleeding
- External cephalic version
- Abdominal trauma
Non-ACOG Members
ACOG Members
* ACOG Evidence grading system
The MEDLINE database, the Cochrane Library, and ACOG's own internal resources and documents were used to conduct a literature search to locate relevant articles published between January 1985 and October 2000. The search was restricted to articles published in the English language. Priority was given to articles reporting results of original research, although review articles and commentaries also were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion in this document.
Guidelines published by organizations or institutions such as the National Institutes of Health and the American College of Obstetricians and Gynecologists were reviewed, and additional studies were located by reviewing bibliographies of identified articles. When reliable research was not available, expert opinions from obstetrician–gynecologists were used. Studies were reviewed and evaluated for quality according to the method outlined by the U.S. Preventive Services Task Force:
- I Evidence: obtained from at least one properly designed randomized controlled trial.
- II -1 Evidence obtained from well-designed controlled trials without randomization.
- II -2 Evidence obtained from well-designed cohort or case–control analytic studies, preferably from more than one center or research group.
- I I-3 Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments also could be regarded as this type of evidence.
- III Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
Based on the highest level of evidence found in the data, recommendations are provided and graded according to the following categories:
- Level A—Recommendations are based on good and consistent scientific evidence.
- Level B—Recommendations are based on limited or inconsistent scientific evidence.
- Level C—Recommendations are based primarily on consensus and expert opinion.
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