Maternal mortality and morbidity related to severe anemia and blood loss remain a major global health concern, particularly in low-resource settings. The World Health Organization (WHO) provides standardized, evidence-based recommendations to guide blood transfusion practices during pregnancy and childbirth. These guidelines are designed to standardize patient care, maximize clinical benefit, and promote the rational use of limited blood resources. The goal is to ensure that women receive safe and timely transfusions. The WHO helps healthcare systems improve outcomes for expectant and new mothers.
Preventing the Need for Transfusion
The guidelines prioritize proactive measures to prevent severe anemia, thereby reducing the dependency on blood transfusion later in pregnancy. Anemia in pregnancy is defined by the WHO as a hemoglobin (Hb) concentration below 11.0 grams per deciliter (g/dL). This threshold is a concern because the physiological increase in blood plasma volume during gestation naturally lowers the concentration of red blood cells, a phenomenon known as hemodilution.
A fundamental recommendation for prevention is daily oral iron and folic acid supplementation for all pregnant women. The standard prophylactic dose is 30 mg to 60 mg of elemental iron paired with 400 micrograms (0.4 mg) of folic acid. In populations where the prevalence of anemia is high (40% or more), the WHO recommends the higher 60 mg elemental iron dose.
Supplementation aims to build and maintain sufficient iron stores to support the mother and developing fetus, as iron demand increases significantly throughout pregnancy. When a woman is diagnosed with iron deficiency anemia, the focus shifts to therapeutic intervention, often using a higher dose of oral iron or intravenous iron if oral treatment fails. These non-transfusion strategies correct the underlying deficiency before the hemoglobin level necessitates a transfusion.
Criteria for Transfusion in Non-Hemorrhagic Conditions
For women with severe anemia who are not actively bleeding, the decision to transfuse is based on clinical symptoms and the absolute hemoglobin level. Transfusion is rarely indicated for asymptomatic anemia, even with moderately low hemoglobin values, because of the associated risks. Red blood cell transfusion is reserved for severe, symptomatic anemia that has not responded to other treatments like iron therapy.
The common threshold for considering a transfusion in a symptomatic, non-bleeding patient is a hemoglobin level below 7.0 g/dL. Symptoms that may prompt a transfusion include signs of organ hypoperfusion, such as shortness of breath, severe fatigue, or heart failure. For patients with specific underlying conditions like sickle cell disease or those approaching delivery, a slightly higher threshold might be considered.
In cases of profound anemia, such as an Hb level falling below 6.0 g/dL, transfusion becomes mandatory to prevent severe complications, even if the patient appears to be compensating. In resource-limited settings, the threshold may be set lower, often at or below 5.0 g/dL in the antepartum period, due to the high mortality risk. Transfusion is a treatment of last resort for chronic anemia, used only when symptoms or extremely low lab values signal a life-threatening compromise.
Management of Acute Obstetric Hemorrhage
Acute obstetric hemorrhage, involving rapid, severe blood loss, is an urgent scenario where transfusion is a direct life-saving intervention. In these emergency situations, the decision to transfuse is driven primarily by clinical signs of shock and hypoperfusion rather than waiting for laboratory results. Signs like low blood pressure and a rapid heart rate indicate the need for immediate action, even if the initial hemoglobin level appears normal.
Initial management focuses on immediate resuscitation, including using intravenous fluids like crystalloids to restore circulating volume while preparing blood products. The WHO supports the use of antifibrinolytic agents, such as tranexamic acid, administered promptly following the onset of bleeding. This pharmaceutical intervention helps stabilize blood clots and reduce ongoing blood loss.
In cases of massive blood loss, a massive transfusion protocol (MTP) is important, even if full component therapy is unavailable. The MTP aims to replace red blood cells, clotting factors, and platelets, often using fixed ratios (e.g., 1:1:1). In resource-limited settings, whole blood may be the most accessible product to address both volume and oxygen-carrying capacity simultaneously. Therapeutic targets aim to maintain a hemoglobin level above 8.0 g/dL and ensure adequate clotting function, specifically a fibrinogen level greater than 2.0 grams per liter.
Ensuring Blood Safety and Administration
The WHO places strong emphasis on the safety and quality control of all blood products used in transfusions. This begins with rigorous screening of all donated blood for transfusion-transmissible infections, including HIV, Hepatitis B and C, and syphilis. Quality assurance systems must be in place throughout the entire process, from collection to administration, to minimize the risk of infection and adverse reactions.
Before any transfusion, compatibility testing (cross-matching) must be performed to prevent life-threatening hemolytic reactions. Proper storage conditions are mandated to maintain the efficacy and sterility of the blood components. The guidelines promote the rational use of blood products, encouraging the use of specific components like packed red blood cells rather than whole blood, to conserve resources and reduce recipient exposure risk.
During the transfusion, the patient must be closely monitored by a trained healthcare provider to detect and manage any adverse reactions immediately. Monitoring of vital signs, including temperature, pulse, and blood pressure, is performed before the transfusion begins, at the 15-minute mark, and then hourly thereafter. This careful oversight ensures the patient receives the blood product safely and without complication.