Transfusion Therapy in Pregnant Sickle Cell Disease Patients National Institutes of Health
Consensus Development Conference Statement
April 23-24, 1979
This statement is more than five years old and is provided solely for historical purposes. Due to the cumulative nature of medical research, new knowledge has inevitably accumulated in this subject area in the time since the statement was initially prepared. Thus some of the material is likely to be out of date, and at worst simply wrong. For reliable, current information on this and other health topics, we recommend consulting the National Institutes of Health's MedlinePlus http://www.nlm.nih.gov/medlineplus/.
This statement was originally published as: Transfusion Therapy in Pregnant Sickle Cell Disease Patients. NIH Consens Statement 1979 Apr 23-24;2(3):17-20For making bibliographic reference to the statement in the electronic form displayed here, it is recommended that the following format be used: Transfusion Therapy in Pregnant Sickle Cell Disease Patients. NIH Consens Statement Online 1979 Apr 23-24 [cited year month day];2(3):17-20.
A Consensus Development Conference on Transfusion Therapy in Pregnant Sickle Cell Disease Patients was held at the National Institutes of Health on April 23-24, 1979.
In general, four consensus work groups explored the question of whether there was sufficient evidence about prophylactic transfusion therapy to advocate its use to treat pregnant sickle cell disease patients. Other aspects of sickle cell disease treatment addressed included the need for further research, including clinical research, perinatal considerations, and socio-medical issues. The work groups were divided into four subject areas--the need for further research, clinical research approaches, perinatal considerations, and sociomedical issues. Each group then reached conclusions on its subject.
Work Group I
Further research in transfusion therapy for pregnant sickle cell disease patients is needed, but the question must be approached in a systematic fashion.
In transfusion therapy, pregnant sickle cell disease patients are divided into two major groups for management. Group 1 is treated symptomatically, but the majority of these patients still receive blood components. Blood transfusions are used whenever judged to be necessary but are not given prophylactically. Group 2 is treated with prophylactic blood transfusions. Transfusion in this group is used to elevate the Hgb and Hct significantly and to suppress Hgb S containing cells, while replacing them with Hgb A cells. Other patients in Group 2 are managed with exchange transfusions.
The following question was posed: Have the positive effects of transfusion therapy for pregnant sickle cell disease patients been satisfactorily proven? The consensus of the group is that the value of this type of transfusion therapy has not been proven. Although most studies regarding transfusion therapy have examined effects on maternal infection, toxemia, jaundice, anemia, sickle cell crisis and hospitalization, and on fetal growth retardation, perinatal mortality, and premature delivery, there is no consensus as to the effects of transfusion on these parameters. Some of the reasons for neither proving nor refuting the value of transfusion therapy are that the problems associated with sickle cell disease and pregnancy are not well defined; previously reported data are retrospective; there are no controls for gathering information about pregnancies in sickle cell disease patients; data regarding patients are not comparable among institutions; and pathophysiologic mechanisms leading to poor outcome in sickle cell disease patients are not understood.
The problems of the pregnant sickle cell disease patient must be defined before there can be an attempt to solve them. Which parameters to study and modify must be determined before the best outcome for both mother and infant can be sought. Because some of the pregnant sickle cell patients seem to be at low risk, a method must be found to determine which mothers need, and which do not need, transfusion therapy.
Studies of pregnant sickle cell patients may shed light on reasons for intrauterine growth retardation, reasons for and management of fetal stress and distress, and on the importance of various parameters in determining degree of risk for individual pregnant sickle cell patients.
Since the positive effects of transfusion therapy have been neither proved nor refuted, a task force for study design should be formed. The task force would develop a protocol for a prospective randomized study to determine the benefits and risks of transfusions in the pregnant sickle cell disease patient. To provide for an adequate data base. The National Cooperative Study of the Clinical Course of Sickle Cell Disease should be expanded to include additional perinatal information decided upon by a task force. Further input should come from interested perinatal centers. This "natural history" study has been funded by NIH for five years and involves 15 medical centers and 23 hospitals.
Studying the problem further indicates that the management of the pregnant sickle cell disease patient is not well established. The impact on the lay population and decisions of the sickle cell disease patient regarding future pregnancies should be carefully considered.
Work Group II
Further research is necessary to define the relationship between outcome and transfusion therapy during pregnancy. To be definitive, this research must be prospective and randomized. Since it is apparent that no one hospital or city has a sufficient patient population to perform such a study within a reasonable interval, a national cooperative multi-center approach should be utilized. The study should be integrated with the ongoing "natural history" study. To be well conducted, such an expensive and extensive task must be given priority, organized through mechanisms of the National Heart, Lung, and Blood Institute, and adequately funded.
Patients should not be excluded from the study on the basis of genotype, but criteria must be developed for those who will be included. For example, is the patient's history helpful? Should Sickle B + thalassemia and patients with greater than or equal to 10% hemoglobin F be included in the study?
Data must be accumulated to determine more fully the risks of transfusion, and methods must be defined for reducing transfusion risks to the minimum. Followup data are mandatory and must include careful collaboration among obstetricians, hematologists, pediatricians, pathologists, and blood banking personnel. In addition, blood typing and processing requirements must be carefully defined.
Patients should be randomized to transfusion or no-transfusion therapy in a prospective way after informed consent has been given. However, patients randomized to "no-transfusion" therapy, may be transfused for specifically defined indications.
Data collection must start as early as possible, and the benefit and timing must be determined by the study design analysis group. Following initial therapy, frequent monitoring of high hemoglobin S levels must be performed and an upper limit defined (possibly from data from the natural history study) which, when exceeded, warrants repeat transfusion. Additionally, maximum hemoglobin levels not to be exceeded, must be defined.
Work Group III
Perinatal considerations for transfusion therapy in sickle cell patients should address these questions:
- How should patient monitoring be considered?
- What are the challenges of intrapartum management?
- What is the approach to infant followup?
A detailed series of clinical and laboratory procedures could be used to follow patients through the ante, intra, and post-partum periods and to establish a data base. The comprehensive nature of the outline recommended reflects the importance of gathering complete data during pregnancy. Important retrospective information might be obtained from these data and prospective therapeutic guidelines developed.
Regardless of the specific guidelines followed for pregnant sickle cell patients, medical care should be provided in a tertiary center, with a joint effort among obstetricians, hematologists, and pediatricians. It should involve awareness of the clinical course of the disease process during pregnancy as well as therapeutic modalities that may modify the course and outcome of pregnancy. Infants born to sickle cell disease patients, who may or may not have had transfusion therapy during pregnancy, should be followed for a minimum of two years.
Since an appropriate study has not been performed to document its value, the detailed list of procedures prepared by the group should not be considered as recommendation for patient management.
Work Group IV
The data are insufficient to advocate a large scale nationwide policy of transfusion therapy or to reach definitive conclusions about ethical considerations. A study to determine (within 1-2 years) in a limited number of centers the value of therapeutic versus prophylactic transfusion in management should be undertaken. However, justification would appear to be the marked difference in opinion as regards the value of various treatment modalities.
Any study design must consider psychological considerations, including patient and physician levels of awareness and knowledge and must allow for prejudice or feelings concerning fear of transfusion, possible intimidation from the community regarding transfusion needle marks (confused with addiction), pressure on family for repeated blood donations, convenience factors favoring time of transfusion for physician versus patient, overprotectiveness of patient's family, and possible "addiction" of patient to transfusion. Economic, geographic, and educational data relating to patient and physician must be considered, and continual updating of information about the progress of the study for all concerned must be planned.
Counseling should be available both pre- and post-conception. Information about the value of amniocentesis in selected instances should be made available to patients. Any study design should take all of the psychosocial aspects into account.
Access to the study must be available to all patients who wish to become involved, but they should not be coerced.
Informed consent should be obtained from all participants. Innovative methods, such as audiovisual presentations with subsequent question and answer sessions, should be developed to avoid coercion of patients. Patient feedback mechanisms to test levels of comprehension need to be developed. Paramedical personnel may need to be included.
Funding for patient care in such a study should be through private or public means and not grant support. Analysis of data and reporting can be related to NIH support, but patient care funding cannot.
The presence of hemoglobin-SS, SC, or sickle thalassemia, which constitute sickle cell disease, should not be the sole justification for either abortion or sterilization. These procedures should be performed on the basis of medical indications and/or patient desire. The medical and legal communities need to be apprised of this consensus.
Consensus Development Panel Co-Chairmen
John C. Morrison, M.D.
University of Tennessee
Henry Foster, M.D.
Meharry Medical College
National Heart, Lung and Blood Institute
Office of Medical Applications of Research