Antepartum Hemorrhage Comprehensive Notes

Antepartum Hemorrhage

Bleeding in later gestation (after viability) is termed antepartum hemorrhage. Management should be based on the sixth edition guidelines due to recent changes. Antepartum hemorrhage complicates approximately 2-5% of all pregnancies and is a leading cause of maternal and perinatal morbidity and mortality.

• Definition: Bleeding from or into the genital tract after the period of viability.

  • Indian guidelines: 28 weeks.

  • Other guidelines (US, developed countries): 20 weeks. These guidelines reflect the point at which a fetus is considered to have a reasonable chance of survival outside the womb.

• Causes:

  • Placenta previa: Placenta is located in the lower uterine segment, covering or adjacent to the internal cervical os.

  • Abruptio placenta: Premature separation of a normally situated placenta from the uterine wall.

  • Vasa previa: Fetal bleeding due to velamentous cord insertion where vessels traverse the internal os. Rupture during dilation leads to fetal blood loss and potential fetal loss. This is a rare but critical cause of APH, carrying a high risk of fetal mortality.

  • Preterm labor: Blood-mixed mucus discharge (show). This is often a benign cause, but it can be a sign of underlying placental issues or the onset of labor.

  • Rarely: Uterine rupture. Uterine rupture is a catastrophic event, most often occurring in women with a prior cesarean section. It can lead to severe hemorrhage and fetal compromise.

• Most common cause: Abruptio placenta (1 in 200 pregnancies). Abruption accounts for approximately 30% of APH cases and is associated with significant maternal and fetal risks.

• Placenta previa incidence: 1 in 300 pregnancies. Placenta previa accounts for approximately 20% of APH cases. The incidence is increasing due to the rising rates of cesarean sections.

Abruptio Placent

Premature separation of a normally situated placenta (upper uterine segment) before fetal delivery. Risk factors include hypertension, smoking, cocaine use, trauma, and prior abruption. Complications can include maternal hemorrhage, DIC, renal failure, and fetal hypoxia, preterm delivery, and stillbirth.

Placenta Previa

Placenta located in the lower uterine segment. The primary risk factor is a prior cesarean section. Other risk factors include multiparity, advanced maternal age, multiple gestation, and smoking. The main complication is hemorrhage, which can be life-threatening for the mother and fetus.

Bleeding Mechanisms

Abruption

• Incitating factors (trauma, PIH, inflammation) cause rupture of spiral arteries in the decidua basalis. The rupture of these arteries initiates a cascade of events leading to placental separation.

• Blood collection leads to placental separation. The accumulating blood forms a retroplacental hematoma, which further separates the placenta from the uterine wall.

• Separation causes more bleeding. As the placenta separates, more spiral arteries rupture, leading to further bleeding and expansion of the hematoma.

• Blood collection behind placenta increases pressure in intervillous spaces. This increased pressure compromises the exchange of oxygen and nutrients to the fetus.

• Increased pressure leads to thromboplastin release. Latest research says thromboplastin is released due to increased pressure in intervillous space.

• Thromboplastin is a uterotonic agent: increases uterine tone. Leads to tense, tender, rigid uterus.

  • Initiates labor. The release of thromboplastin can trigger premature labor.

  • Can cause DIC. Disseminated intravascular coagulation (DIC) is a life-threatening condition characterized by widespread activation of the clotting cascade, leading to depletion of clotting factors and hemorrhage.

• Concealed vs. revealed abruption: Concealed: Blood collects behind the placenta, increasing DIC risk.

  • Revealed: Bleeding comes out. Revealed abruptions are easier to diagnose, but concealed abruptions carry a higher risk of DIC due to the trapped blood and thromboplastin release.

Placenta Previa

• Uterine contractions or cervical changes cause shearing forces on the inelastic placental attachment site in the lower uterine segment. The lower uterine segment is less elastic than the upper segment, making the placenta more vulnerable to shearing forces.

• Shearing forces open venous sinuses in the intervillous space, causing bleeding. The bleeding is typically maternal in origin.

• No spiral artery rupture or placental detachment involved. This is a key difference between placenta previa and abruption.

• No retroplacental clot formation, so no thromboplastin release. The absence of thromboplastin release reduces the risk of DIC.

• Less DIC risk. DIC is rare in placenta previa unless there is significant blood loss leading to hypovolemic shock.

• Uterus is relaxed, soft, and non-tender. This is a classic finding in placenta previa and helps to differentiate it from abruption.

• No inciting factors, bleeding due to shearing forces. The bleeding is typically painless and occurs without any identifiable trigger.

• Intercourse and per vaginal examination contraindicated due to increased contraction risk. These activities can disrupt the placenta and cause further bleeding.

• Transvaginal ultrasound (TVS) is not contraindicated; probe is placed below the internal os, and it is the investigation of choice. TVS provides a more accurate assessment of the placental location than transabdominal ultrasound.

Initial Management of Antepartum Hemorrhage

1. Resuscitation of the mother. Two large bore IV cannulas (14G - orange, 16G - gray). Large-bore IVs are essential for rapid fluid and blood product administration.

   • Blood samples: ABO Rh typing, CBC, bleeding/clotting time, coagulation profile. These tests help to assess the severity of blood loss and identify any underlying coagulopathies.

   • Start Ringer Lactate or IV infusions. Crystalloid solutions like Ringer's Lactate are used for initial volume resuscitation.

   • Oxygen via mask. Supplemental oxygen helps to improve maternal oxygen saturation and fetal oxygenation.

   • Maintain airway, breathing, circulation. These are the basic principles of resuscitation.

2. Assess placenta previa or abruption risk based on history and per abdominal examination. Abruption: Tense, tender, rigid uterus.

   • Placenta previa: Soft, non-tender, relaxed uterus. The uterine examination is crucial in differentiating between previa and abruption.

   • Per vaginal examination is contraindicated unless placenta previa is ruled out. PVE can cause severe hemorrhage if placenta previa is present.

3. Check patient vitals after initial resuscitation. Monitor vital signs closely for signs of hypovolemia and shock.

Stable Vitals

• Transabdominal scan to check for placenta previa or abruption. Placenta in lower segment: Placenta previa, proceed to transvaginal scan.

  • Retroplacental clot, placental thickening, or "jello sign" (shimmering of placenta): Abruptio. Abruptio is a clinical diagnosis. Absence of findings on scan doesn't rule out abruption. Ultrasound findings in abruption can be subtle and may not always be present.

Unstable Vitals or Fetal Distress

• Immediate cesarean section, do not delay for ultrasound. In cases of severe bleeding or fetal compromise, immediate delivery is necessary to save the lives of the mother and fetus.

• Ultrasound is not diagnostic of abruption; it only aids in diagnosis. The diagnosis of abruption is primarily clinical.

Placenta Localization

• Accurate diagnosis of placenta previa/low lying placenta can be made by 16 weeks via ultrasound. Early ultrasound can identify potential previa, but it's not definitive.

• Diagnosis should not be made at this time because of trophoptropism. Trophoptropism refers to the preferential growth of the placenta towards the upper, better-vascularized portion of the uterus.

• In 90% of cases placenta migrates up to the upper uterine segment by the third trimester. This "placental migration" is due to the differential growth of the uterus.

• Placental migration occurs due to differential growth of the uterus. Lower uterine segment is formed from the isthmus.

  • Isthmus is 5mm in length in non-pregnant female.

  • During pregnancy it goes to 5cm in 3rd trimester. The lengthening of the isthmus contributes to the apparent migration of the placenta.

• Best time to do ultrasound for localization of placenta is in the third trimester. This allows for a more accurate assessment of the placental location after the majority of placental migration has occurred.

• If placenta is low lying in first or second trimester, repeat ultrasound at 32 weeks gestation.

  • If placenta in upper segment, follow routine antenatal care.

  • If placenta remains in lower segment, repeat ultrasound at 36 weeks.

Risk Factors for Placenta Previa

• Previous history of placenta previa (5% recurrence rate). Women with a prior previa have a significantly increased risk of recurrence in subsequent pregnancies.

• Factors leading to a big placenta: Twin pregnancy.

  • Placenta bilobata.

  • Smoking: Carbon monoxide hypoxemia leads to placental hypertrophy. Smoking is a well-established risk factor for placenta previa.

• Factors preventing migration of the placenta: Uterine scar (cesarean section, hysterotomy). Risk increases with the number of cesarean sections.

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• Present history of placenta previa and previous history of cesarean section is a risk factor for PAS (placenta accreta spectrum). Placenta accreta spectrum is a condition in which the placenta abnormally adheres to the myometrium.

• Doppler study should be done to rule out placenta accreta spectrum. Doppler ultrasound can assess the placental-myometrial interface and identify signs of accreta.

• Other risk factors: Increased maternal age.

  • Increased maternal parity.

  • Assisted reproductive techniques (IVF). Increased maternal age.

    • Increase chances of twin pregnancy and multi fetal gestation.

  • Increased maternal serum alpha fetoprotein levels. Elevated MSAFP levels have been associated with an increased risk of placenta previa.

Classification of Placenta Previa

New Classification

• Placenta previa: Placenta covers the internal os partially or completely.

• Low lying placenta: Placenta reaches within 2 cm of the internal os but doesn't reach it.

Older Classification

• Type 1 (Lateral): Placenta is in the lower uterine segment, but doesn't reach the internal os.

• Type 2 (Marginal): Placenta reaches margins of the internal os, but doesn't cover it.

• Type 3 (Partial): Placenta partially covers the internal os.

• Type 4 (Complete/Central): Placenta completely covers the internal os.

Based on Previous Classification

• Types 1 and 2 (anterior) were minor degrees.

• Type 2 (posterior), types 3 and 4 were major degrees.

• Type 2 (posterior) was known as the dangerous variety because it lead to excessive bleeding. The posterior location makes it more difficult to access and manage bleeding.

• Stall worthy Sign: In posterior placenta previa (types 1 and 2), pushing fetal head into pelvis abdominally causes fetal distress due to cord compression. This sign is rarely used in modern practice.

Clinical Features of Placenta Previa:

Management of Placenta Previa:

Incidental Finding on Level II Scan:

• If second trimester and placenta low lying: 90% will migrate up to the third trimester.

  • Less likely to migrate if posterior or covers >=25 mm of internal os. These factors increase the likelihood that the previa will persist.

  • Advise to avoid heavy lifting, strenuous exercise, prolonged standing, intercourse. These precautions are aimed at reducing the risk of bleeding.

  • Repeat TVS in the third trimester.

TVS Results

• @32 weeks: If placenta migrated up, follow routine antenatal care. If low-lying or placenta previa, repeat TVS at 36 weeks.

• @36 weeks: if placenta migrated up, follow routine antenatal care. If placenta previa is confirmed, plan for repeat cesarean section between 36 and 37 weeks + 6 days. Delivery timing aims to balance fetal maturity with the risk of hemorrhage. If low-lying, discuss risks/benefits of vaginal delivery:

Low-Lying Placenta 36 weeks Follow Up (Within 2cm):

• If less than 1 cm from internal os, plan cesarean section. The risk of hemorrhage with vaginal delivery is too high.

• If 1-2 cm from internal os, cesarean better, but may consider vaginal delivery if patient insists. Vaginal delivery may be attempted with careful monitoring and preparation for immediate cesarean section if needed.

Transvaginal Ultrasound

• Confirm diagnosis

• Detect malpresentations

• Rule out placenta accreta.

Cesarean Section

• Generally, Neuraxial Anesthesia is given. Neuraxial anesthesia (spinal or epidural) is preferred in most cases.

• If DIC present general anesthesia is given. General anesthesia may be necessary in cases of severe hemorrhage or DIC.

Placenta Previa and Previous Cesarean Section

• Increased risk of placenta accreta spectrum

• Color doppler exclusion of placenta accreta

Known Case of Placenta Previa with Bleeding:

1. Resuscitate the patient.

2. Assess for immediate delivery (active management) or prolong pregnancy (expectant management). The decision depends on the severity of bleeding, gestational age, and fetal status.

3. Goal of expectant management: prolong the pregnancy such that fetal lungs mature.

Active Management (Immediate Delivery):

• Hemodynamic instability.

• Continuous, severe, persistent bleeding.

• Significant blood loss at >=34 weeks gestation.

• Active labor.

• Fetal distress.

• Gross congenital anomaly inconsistent with life.

Expectant Management (Johnson and McCaffey Regime):

1. All 5 must be fulfilled: Vitals of the patient should be stable.

   • Fetal heart sounds should be normal.

   • No active bleeding.

   • Gestational age <34 weeks (+34 weeks: individualized plan depends on bleeding severity). Expectant management is generally not recommended after 34 weeks.

   • On ultrasound, congenital anomalies which are compatible with life.

2. Steps to take: Admit the patient.

   • Administer Corticosteroids. Corticosteroids are given to accelerate fetal lung maturation.

   • Tocolytics, if uterine contractions are present for 48 hours. Tocolytics are used to suppress uterine contractions and prolong pregnancy. Nifedipine (tocolytic of choice).

     • Nifedipine (tocolytic of choice).

     • Endomethacin is an antiplatelet drug and that should not be used.

     • Terbutaline shouldn't be used because of masking of shock signs.

   • Magnesium sulfate, if gestational age <32 weeks. Magnesium sulfate is given for neuroprotection of the fetus.

   • Correct hemoglobin levels (goal>10g%). Transfusion may be necessary to maintain adequate oxygen-carrying capacity.

   • Anti-D if Rh negative. Rhogam is given to prevent Rh sensitization in Rh-negative mothers.

   • Fetal Monitoring: NST weekly, BPP, and Ultrasound for GR. Regular fetal monitoring is essential to assess fetal well-being.

   • *No role of cervical cerclage
     

     *Termination of pregnancy: 36-37 weeks + 6 days