Antepartum Hemorrhage Cheatsheet

Cheatsheet Content

Antepartum Hemorrhage (APH) Definition: Bleeding from the genital tract after 24 weeks of gestation (when the fetus is considered viable) but before the birth of the baby. It is a medical emergency that can threaten the life of both the mother and the fetus. Causes and Pathophysiology 1. Placenta Previa Definition: A condition where the placenta (the organ that provides oxygen and nutrients to the growing baby) implants (attaches) in the lower uterine segment (the bottom part of the uterus, near the cervix) and partially or completely covers the internal cervical os (the opening of the cervix into the uterus). Mechanism of Bleeding: As the lower uterine segment forms and stretches in the third trimester (the last three months of pregnancy) and during labor, the placental attachment site is disrupted. This stretching and thinning of the lower uterine segment causes the delicate blood vessels in the placenta to tear away from the uterine wall, leading to bleeding. The bleeding is typically painless because there is no associated uterine contraction causing pain. Types: Complete/Total: The placenta completely covers the internal os. Partial: The placenta partially covers the internal os. Marginal: The edge of the placenta reaches the margin of the internal os. Low-lying: The placenta is in the lower uterine segment but its edge is within 2 cm of the internal os, not covering it. 2. Placental Abruption (Abruptio Placentae) Definition: The premature (before birth) separation of a normally implanted placenta from the uterine wall. This means the placenta detaches from its usual position in the upper part of the uterus. Mechanism of Bleeding: The exact cause is often unknown, but it typically involves a rupture of maternal decidual (the uterine lining during pregnancy) blood vessels. This leads to the formation of a retroplacental hematoma (a collection of blood behind the placenta). The expanding hematoma then shears (tears) the placenta away from the uterine wall, causing bleeding. This separation disrupts the blood supply to the fetus and causes pain due to uterine contractions and irritation from the blood. Types of Bleeding: Revealed hemorrhage: Blood escapes through the cervix and is visible externally. This often underestimates the true amount of blood loss, as some blood may remain trapped behind the placenta. Concealed hemorrhage: Blood is trapped behind the placenta and does not exit through the cervix. This can lead to a large retroplacental hematoma and severe maternal and fetal compromise without visible external bleeding. The uterus becomes tense and tender. 3. Vasa Previa Definition: A rare condition where fetal blood vessels (from the umbilical cord) cross or run in the fetal membranes (the amniotic sac) unprotected by placental tissue or umbilical cord, over the internal cervical os. Mechanism of Bleeding: These unprotected fetal vessels are vulnerable to compression or rupture, especially during cervical dilation (opening of the cervix) or rupture of membranes (water breaking). When these vessels rupture, it results in fetal blood loss, which can be rapidly fatal to the fetus due to hypovolemic shock (shock due to severe blood loss). Maternal bleeding does not typically occur in vasa previa unless there is an associated placental issue. 4. Uterine Rupture Definition: A tear in the wall of the uterus. This is a rare but catastrophic event. Mechanism of Bleeding: A previous uterine scar (e.g., from a prior C-section, myomectomy - removal of fibroids) is the most common predisposing factor. During labor or with strong contractions, the scar can give way, causing the uterine wall to tear. This leads to massive internal bleeding into the maternal abdominal cavity and often expulsion of the fetus into the abdomen. It causes severe abdominal pain and signs of maternal shock. 5. Local Causes (Non-Placental) Cervical Ectropion (Erosion): The columnar epithelium (a type of cell lining found inside the cervix) normally line the endocervix (the canal inside the cervix) extends onto the ectocervix (the outer part of the cervix). This tissue is more fragile and can bleed easily on contact (e.g., during intercourse or examination). The bleeding is usually scant and self-limiting. Cervical Polyps: Benign (non-cancerous) growths on the cervix that are often highly vascular (contain many blood vessels) and can bleed easily, especially after touch or intercourse. Cervical Carcinoma: Malignant (cancerous) growth of the cervix. The abnormal, fragile, and highly vascular tissue can bleed spontaneously or on contact. Vaginal Trauma/Infection: Trauma to the vagina or severe vaginal infections can cause bleeding. Vaginal Varices: Dilated (swollen) veins in the vagina, which can rupture and bleed. Clinical Presentation and Symptoms 1. Placenta Previa Painless vaginal bleeding: This is the hallmark symptom. The bleeding is typically bright red (fresh blood) and can range from spotting to torrential (heavy) hemorrhage. It usually occurs suddenly and without warning. Mechanism of pain absence: The bleeding results from the tearing of blood vessels due to the stretching of the lower uterine segment, not from painful uterine contractions. Soft, non-tender uterus: The uterus remains relaxed and soft between contractions (if any are present), unlike in placental abruption. Fetal presentation abnormalities: Breech (feet-first) or transverse (sideways) presentation may be more common because the placenta occupies the lower uterine segment, preventing the fetal head from engaging (entering the pelvis). 2. Placental Abruption Painful vaginal bleeding: The bleeding can be revealed (visible externally) or concealed (trapped internally). The pain is constant, severe, and localized to the abdomen or back. Mechanism of pain: The pain results from uterine contractions, the accumulation of blood (hematoma) behind the placenta stretching the uterine wall, and irritation of the uterine muscle by blood. Tender, rigid (woody) uterus: The uterus feels hard and board-like on palpation (examination by touch) due to continuous contraction and internal bleeding. Fetal distress: The baby's heart rate may show abnormalities (e.g., decelerations, bradycardia - slow heart rate) due to reduced oxygen supply from placental separation. Maternal shock: Signs of hypovolemic shock (e.g., low blood pressure, rapid heart rate, pallor - paleness) may be present, often disproportionate to the visible blood loss in concealed abruption. Coagulopathy (Disseminated Intravascular Coagulation - DIC): Severe abruption can consume clotting factors, leading to impaired blood clotting and further bleeding. This is due to the release of tissue factor from the damaged placenta into the maternal circulation, triggering the coagulation cascade systemically. 3. Vasa Previa Painless vaginal bleeding: The bleeding typically occurs shortly after rupture of membranes (either spontaneous or artificial). The blood is usually fetal, leading to rapid fetal compromise. Fetal bradycardia/distress: A sudden drop in fetal heart rate immediately after membrane rupture and bleeding is highly suggestive of vasa previa, as the fetus is rapidly losing its own blood. Small amount of blood: Often only a small amount of dark red blood is seen, but this small amount represents significant blood loss for the fetus. 4. Uterine Rupture Sudden, severe abdominal pain: Often described as a "tearing" sensation, followed by cessation of uterine contractions if labor was ongoing. Vaginal bleeding: Can be absent, mild, or severe. Maternal shock: Rapid onset of hypovolemic shock (low blood pressure, rapid heart rate, pallor) due to internal hemorrhage. Fetal distress/demise: Fetal heart rate abnormalities or absence of fetal heart sounds are common due to loss of uterine environment and blood supply. Palpable fetal parts: If the fetus has extruded into the abdominal cavity, its parts may be easily felt under the maternal abdominal wall. Recession of presenting part: The fetal presenting part (e.g., head) may move upwards out of the pelvis. 5. Local Causes Spotting or light bleeding: Usually not heavy, often bright red. Post-coital bleeding: Bleeding after sexual intercourse. Pain: Usually absent, unless due to infection or trauma. Investigations 1. Initial Assessment and Resuscitation Maternal Vitals: Blood Pressure (BP), Heart Rate (HR), Respiratory Rate (RR): To assess for signs of maternal shock (e.g., hypotension - low BP, tachycardia - rapid HR). Oxygen Saturation: To assess oxygenation. Temperature: To rule out infection. Fetal Heart Rate Monitoring (Cardiotocography - CTG): Purpose: To assess fetal well-being, including baseline heart rate, variability, accelerations, and decelerations. This helps detect fetal distress, which is common in placental abruption or vasa previa. Mechanism: CTG records fetal heart rate (FHR) and uterine contractions. Changes in FHR patterns (e.g., prolonged decelerations, reduced variability) indicate fetal hypoxia (lack of oxygen) or acidosis. Intravenous (IV) Access: Purpose: Two large-bore IV cannulae (tubes) are inserted immediately to allow for rapid fluid resuscitation and blood transfusion if needed. Mechanism: Large-bore cannulae (e.g., 14 or 16 gauge) allow for faster fluid and blood administration to combat hypovolemia (low blood volume). Blood Tests: Full Blood Count (FBC): Hemoglobin (Hb): To assess the degree of anemia (low red blood cell count) due to blood loss. Platelets: To check for thrombocytopenia (low platelet count), which can worsen bleeding or indicate DIC. Coagulation Profile (Prothrombin Time - PT, Activated Partial Thromboplastin Time - APTT, Fibrinogen): Purpose: To assess the maternal clotting ability, especially crucial in severe placental abruption where DIC can occur. Mechanism: PT and APTT measure the time it takes for blood to clot, indicating deficiencies in clotting factors. Fibrinogen is a key protein involved in clot formation. Blood Group and Cross-match: Purpose: To prepare for potential blood transfusion by identifying the patient's blood type and finding compatible donor blood. Urea and Electrolytes (U&E): Purpose: To assess kidney function, which can be impaired in severe hypovolemic shock, and electrolyte balance. Kleihauer-Betke Test: Purpose: To detect fetal red blood cells in the maternal circulation. Mechanism: Fetal hemoglobin is more resistant to acid elution than adult hemoglobin. This test helps quantify the amount of fetomaternal hemorrhage, which is important for determining the dose of anti-D immunoglobulin (Rh-negative mothers carrying Rh-positive babies are given anti-D to prevent isoimmunization). 2. Imaging Ultrasound Scan (USS): Purpose: The primary imaging modality for diagnosing placenta previa and assessing fetal well-being. It can also sometimes detect placental abruption, though not always reliably. Mechanism: High-frequency sound waves are used to create images of the uterus, placenta, and fetus. In Placenta Previa: Visualizes the placenta's position relative to the internal cervical os. Transvaginal ultrasound (TVUS) is usually more accurate than transabdominal ultrasound (TAUS) for confirming placenta previa because it provides a clearer view of the lower uterine segment. In Placental Abruption: May show a retroplacental hematoma, but its absence does not rule out abruption, especially if the clot is small or isoechoic (has the same echogenicity as surrounding tissue). It can also assess fetal growth, amniotic fluid volume, and rule out other causes of bleeding. In Vasa Previa: Can visualize fetal vessels crossing the internal os, especially with color Doppler (which detects blood flow). In Uterine Rupture: May show free fluid (blood) in the abdomen or abnormal fetal position. 3. Speculum Examination Purpose: To identify the source of bleeding (cervical, vaginal) and rule out local causes, *only after placenta previa has been excluded by ultrasound*. Mechanism: A speculum (a medical instrument) is gently inserted into the vagina to visualize the cervix and vaginal walls. Caution: A speculum examination or digital vaginal examination is absolutely contraindicated (should not be performed) if placenta previa is suspected or confirmed, as it can trigger massive hemorrhage by disrupting the placenta further. Management and Treatment 1. General Principles (for all APH) Immediate Hospitalization: All women with APH require urgent admission to a hospital for close monitoring and management. Resuscitation: Airway, Breathing, Circulation (ABC): Ensure patent airway, adequate breathing, and support circulation with IV fluids (crystalloids like normal saline or Ringer's lactate) and blood products (packed red blood cells, fresh frozen plasma, platelets) as needed. Oxygen Administration: To improve maternal and fetal oxygenation. Continuous Fetal Monitoring: CTG to assess fetal well-being and detect distress. Anti-D Immunoglobulin: Administer to Rh-negative mothers with APH to prevent Rh alloimmunization (formation of antibodies against fetal red blood cells), as fetomaternal hemorrhage may occur. 2. Specific Management for Placenta Previa Expectant Management (if stable, preterm, and bleeding is mild): Goal: To prolong pregnancy to improve fetal lung maturity. Requires: Stable maternal condition, no active bleeding or only mild spotting, reassuring fetal status. Involves: Close monitoring in hospital, bed rest, pelvic rest (no intercourse, no vaginal exams). Corticosteroids (e.g., Betamethasone): Administered to the mother between 24-34 weeks gestation (or up to 36+6 weeks in some cases) to accelerate fetal lung maturity, reducing the risk of respiratory distress syndrome if preterm delivery becomes necessary. Delivery (C-section): Indication: Active heavy bleeding, signs of maternal or fetal compromise, or reaching term gestation. Route: Cesarean section (C-section) is almost always indicated for placenta previa, especially complete or partial previa, to avoid severe hemorrhage that would occur if the cervix dilates and disrupts the placenta during vaginal birth. Timing: Usually planned around 36-37 weeks for stable cases to minimize the risk of spontaneous labor and hemorrhage, while maximizing fetal maturity. 3. Specific Management for Placental Abruption Immediate Delivery: Indication: If the abruption is severe, or if there is fetal distress or significant maternal compromise, immediate delivery is the priority. Route: Cesarean Section: Often preferred for severe abruption, especially with fetal distress, to expedite delivery. Vaginal Delivery: May be considered if the abruption is mild, the mother is stable, the fetus is not distressed, and labor is progressing rapidly. Amniotomy (artificial rupture of membranes) may be performed to reduce uterine pressure and potentially shorten labor. Fluid and Blood Product Resuscitation: Aggressive management of hypovolemic shock and coagulopathy with IV fluids, packed red blood cells, fresh frozen plasma, and platelets is critical. Monitoring for DIC: Close monitoring of coagulation parameters and clinical signs of bleeding. 4. Specific Management for Vasa Previa Planned Cesarean Section: Indication: If diagnosed antenatally (before birth), a planned C-section is recommended before the onset of labor and rupture of membranes, typically between 34-36 weeks, to prevent fetal exsanguination (bleeding to death). Corticosteroids: Administered to promote fetal lung maturity if delivery is planned preterm. Emergency Cesarean Section: Indication: If bleeding occurs with rupture of membranes, immediate emergency C-section is required to save the fetus. 5. Specific Management for Uterine Rupture Emergency Laparotomy and Delivery: Indication: Immediate surgical intervention is required. Procedure: The abdomen is opened (laparotomy), the baby is delivered, and the uterus is inspected. The tear in the uterus is then repaired (hysterorrhaphy). Hysterectomy: In cases of severe, irreparable rupture or uncontrolled bleeding, a hysterectomy (removal of the uterus) may be necessary to save the mother's life. Resuscitation: Aggressive fluid and blood product resuscitation is crucial to manage hemorrhagic shock. 6. Specific Management for Local Causes Conservative Management: For benign causes like cervical ectropion or polyps, reassurance and observation are often sufficient as bleeding is usually minor and self-limiting. Treatment of Underlying Cause: Cervical Polyps: May be removed (polypectomy) if bleeding is troublesome, usually after delivery. Infections: Treated with appropriate antibiotics. Cervical Carcinoma: Requires specific oncological management, which may involve surgery, radiation, or chemotherapy, often after delivery or with consideration for pregnancy termination depending on gestational age and stage of cancer.