Fetal hemorrhage refers to bleeding that originates from the developing baby, occurring either internally within the fetus or externally into the surrounding environment, before or during birth. This condition is a serious medical emergency due to rapid blood loss. Though rare, it threatens the infant’s health and survival, requiring prompt recognition and intervention.
Understanding Fetal Hemorrhage
Fetal hemorrhage is the loss of blood from the fetus, manifesting in distinct forms based on location. One common type is fetomaternal hemorrhage (FMH), where fetal red blood cells enter the mother’s circulation, often crossing the placental barrier. In multiple gestations, particularly with monochorionic twins, feto-fetal hemorrhage can occur. This involves the transfer of blood from one twin to the other through shared placental connections, as seen in twin-to-twin transfusion syndrome. Bleeding can also occur directly from fetal vessels, such as those within the umbilical cord or placenta, leading to blood loss into the amniotic fluid or other fetal compartments.
The physiological impact differs from maternal bleeding; the fetus has a much smaller blood volume, making minor losses proportionally more severe. A typical full-term fetus has a total blood volume of approximately 80-100 mL per kilogram of body weight. Severity relates directly to the volume and rate of blood loss, with rapid or substantial losses quickly leading to anemia and hypovolemic shock. This reduction in circulating blood volume impairs oxygen delivery to fetal tissues, potentially causing widespread organ damage.
Causes of Fetal Hemorrhage
Several conditions can lead to fetal hemorrhage, often involving disruptions in the connection between the mother and fetus via the placenta and umbilical cord. Placental issues are a frequent cause, including placenta previa, where the placenta covers the cervix, and placental abruption, which involves the premature detachment of the placenta from the uterine wall. Vasa previa, a condition where fetal blood vessels cross or run near the internal opening of the uterus beneath the baby, presents a high risk of rupture during labor. Velamentous cord insertion, where the umbilical cord inserts into the membranes rather than the center of the placenta, leaves unprotected vessels vulnerable to tearing.
Abnormalities or trauma to the umbilical cord can also result in bleeding. This includes cord rupture, spontaneous or due to tension, or direct injury during procedures like amniocentesis. In monochorionic twin pregnancies, twin-to-twin transfusion syndrome (TTTS) can cause chronic feto-fetal hemorrhage.
Fetal conditions can also predispose a baby to hemorrhage, such as inherited bleeding disorders like hemophilia, which impair the blood’s ability to clot. Highly vascular fetal tumors, though rare, can also cause significant blood loss. External abdominal trauma to the pregnant person, such as from a fall or motor vehicle accident, can injure the placenta or fetal vessels. Invasive prenatal procedures, including cordocentesis or fetoscopy, carry a risk of bleeding from fetal vessels.
Identifying Fetal Hemorrhage
Detecting fetal hemorrhage often begins with recognizing maternal symptoms, though these can be non-specific and require medical evaluation. A pregnant person might notice vaginal bleeding, which can range from spotting to heavy flow, or experience abdominal pain and uterine tenderness. A concerning sign is a sudden decrease in fetal movement, indicating potential fetal distress due to reduced oxygen supply. These symptoms alone do not confirm fetal hemorrhage and require prompt medical attention to determine the source.
Healthcare providers use various diagnostic procedures to identify and quantify fetal hemorrhage. Ultrasound scans visualize the placenta and fetus, revealing signs like placental abnormalities, hydrops fetalis, or retroplacental hematomas. Doppler studies assess blood flow patterns in fetal vessels, helping to identify anemia or vascular compromise. Specific blood tests are also performed, including the Kleihauer-Betke test or flow cytometry, which detect and quantify fetal red blood cells in the maternal circulation, confirming fetomaternal hemorrhage.
Continuous fetal heart rate monitoring detects fetal distress, a common consequence of significant blood loss. Patterns such as persistent decelerations, reduced variability, or a sinusoidal heart rate pattern can indicate severe fetal anemia or hypoxia. These monitoring findings, combined with maternal symptoms and diagnostic imaging or laboratory results, provide a comprehensive picture to confirm the presence and severity of fetal hemorrhage. Early and accurate identification is important for timely intervention and improved outcomes.
Treatment Approaches
Immediate stabilization of the pregnant person and fetus is the initial focus when fetal hemorrhage is suspected or confirmed. If the pregnant person shows signs of hypovolemia due to significant blood loss, intravenous fluid resuscitation may be initiated to maintain circulatory stability, supporting placental blood flow to the fetus. The overall management strategy depends on the hemorrhage’s severity, the fetus’s gestational age, and the presence of ongoing bleeding.
For severe fetal anemia caused by hemorrhage, intra-uterine blood transfusions (IUT) are a primary treatment. This procedure involves injecting donor red blood cells directly into the fetal umbilical vein under ultrasound guidance to replenish lost blood volume and correct anemia. IUTs improve the fetus’s oxygen-carrying capacity, alleviate distress, and allow for further fetal maturation if hemorrhage has stabilized. Multiple transfusions may be required, depending on the fetus’s response and ongoing blood loss.
Early delivery, either vaginally or via C-section, is considered when the fetus is mature enough to tolerate birth, and hemorrhage is severe, ongoing, or unmanageable with transfusions. This intervention removes the fetus from the compromised intrauterine environment, allowing for direct neonatal resuscitation and management. Supportive care for the pregnant person and fetus continues, involving close monitoring of vital signs and fetal well-being. Addressing the underlying cause, such as managing placental abruption through observation or delivery, is also a component of comprehensive treatment.
Potential Outcomes
Outcomes for an infant who has experienced fetal hemorrhage vary widely, depending on the cause, volume and rate of blood loss, gestational age, and treatment effectiveness. In the short term, significant fetal hemorrhage can lead to severe anemia, which reduces the oxygen-carrying capacity of the blood. This can result in hypoxia, or insufficient oxygen supply to tissues, potentially causing damage to organs such as the brain and heart. In severe and unmanaged cases, fetal hemorrhage can lead to stillbirth or neonatal death shortly after birth.
Infants who survive severe fetal hemorrhage, particularly with prolonged oxygen deprivation, may face developmental issues. These can include neurological impairments such as cerebral palsy, which affects muscle movement and coordination. Other potential long-term challenges might involve cognitive or motor delays. The prognosis is more favorable with early detection, timely intervention, and comprehensive postnatal care.