Plasma is the straw-colored liquid component of blood that makes up over half of its volume, carrying proteins, water, salts, enzymes, and antibodies throughout the body. Donating plasma involves a process called apheresis, where the plasma is separated from the red blood cells, and the remaining blood components are returned to the donor. While this donation process is generally safe for healthy individuals, a woman cannot donate plasma while pregnant. This mandatory deferral protects the health of both the donor and the recipient, based on regulatory standards and specific medical concerns regarding the physiological changes of pregnancy.
Regulatory Stance on Plasma Donation
The guidelines established by regulatory bodies like the U.S. Food and Drug Administration (FDA) and organizations such as AABB create a standardized and mandatory deferral for pregnant individuals. This restriction is not a local policy decision but a non-negotiable requirement for all plasma donation centers across the industry. The regulatory basis for this disqualification is comprehensive, covering both donor well-being and the safety of the final plasma product. The rules are designed to prevent donation during the entire period of gestation, recognizing the significant and rapid changes occurring in the body. Plasma donation centers must adhere to these standards, making pregnancy an automatic and temporary medical deferral from the donation process.
Medical Rationale for Donor Safety
The body undergoes physiological adjustments during pregnancy to support the developing fetus, which makes plasma donation unsafe for the mother. A woman’s blood volume increases by 30 to 50 percent during pregnancy, an adaptation that helps meet the demands of the placenta and protects against blood loss during delivery. Removing a significant volume of plasma during the apheresis procedure can cause volume depletion, potentially leading to adverse effects like dizziness, hypotension, or fainting. Furthermore, plasma donation involves temporarily removing proteins and fluids, which are already in high demand to support fetal growth and the mother’s expanded circulatory system. Removing plasma can exacerbate the common risk of iron deficiency anemia, as pregnancy places a heavy demand on the body’s nutrient stores.
Product Safety Concerns: Alloimmunization Risk
The most significant concern for the recipient of the plasma relates to alloimmunization, which occurs when the immune system develops antibodies against foreign antigens. During pregnancy, a small amount of the baby’s blood, which carries paternal Human Leukocyte Antigens (HLA), can enter the mother’s bloodstream. The mother’s immune system recognizes these paternal HLA markers as foreign and produces specific HLA antibodies against them. These antibodies, found in the mother’s plasma, pose a serious threat to a transfusion recipient.
If the donated plasma containing these HLA antibodies is transfused, the antibodies can react with the recipient’s white blood cells, potentially triggering a severe reaction. This reaction is known as Transfusion-Related Acute Lung Injury (TRALI), a life-threatening complication characterized by acute respiratory distress and non-cardiogenic pulmonary edema. TRALI is considered the leading reported cause of transfusion-related fatalities, and plasma products from previously pregnant women are disproportionately implicated in these cases. To mitigate this risk, blood centers avoid using high-plasma-volume products from women who have been pregnant, unless they test negative for HLA antibodies. The presence of these antibodies does not harm the mother or her baby, but it necessitates a restriction on her plasma donation.
Resuming Donation After Pregnancy
After childbirth, a woman must observe a mandated waiting period before she can resume donating blood products. For whole blood donation, the standard deferral time is typically six weeks postpartum, allowing the body time to recover from delivery and replenish its iron and blood volume stores. However, the timeline for resuming plasma donation is more complex due to the risk of HLA antibodies. The recovery period is often longer, with some centers recommending a minimum waiting period of six months after delivery, miscarriage, or termination of pregnancy. Eligibility to donate plasma requires a specific blood test to screen for the presence of HLA antibodies, and a positive result may lead to a permanent deferral from donating plasma and high-plasma-volume products.