Antepartum Hemorrhage

• Antepartum Hemorrhage


  Obstetric hemorrhage is a leading cause of maternal death in the United States and one of the leading causes of perinatal morbidity and mortality
• In 2005, hemorrhage was the third leading cause of maternal deaths due to obstetric factors in the United States
• Causes of third-trimester vaginal bleeding

  • Obstetric
  • Nonobstetric
• Placenta previa


  Abnormal implantation of the placenta over the internal cervical os
• Types of placenta previa

  • Complete previa
  • Partial previa
  • Marginal previa
  • Low-lying placenta
• Placental migration


  Apparent movement of the placenta, most likely due to the development of the lower uterine segment
• Vasa previa


  Fetal vessel lying over the cervix
• Succenturiate lobe


  Placental lobe discrete from the rest of the placenta
• Bleeding from placenta previa

  1. Small disruptions in the placental attachment during normal development

  2. Thinning of the lower uterine segment during the third trimester

  3. Stimulates further uterine contractions

  4. Further placental separation and bleeding
• Maternal mortality is estimated to occur in 0.03% of cases of placenta previa in the United States
• Perinatal mortality rate is still 10 times higher than in the general population
• Fetal risks associated with placenta previa

  • Preterm delivery and its complications
  • Preterm premature rupture of membranes
  • Intrauterine growth restriction
  • Malpresentation
  • Vasa previa
  • Congenital abnormalities
• Placenta accreta


  Superficial attachment of the placenta to the uterine myometrium
• Placenta increta


  Placenta invades the myometrium
• Placenta percreta


  Placenta invades through the myometrium to the uterine serosa
• The average blood loss at delivery in women with placenta accreta is 3,000 to 5,000 mL
• Two-thirds of women with both a placenta previa and an associated accreta require a hysterectomy at the time of delivery
• Placenta accreta may lead to spontaneous uterine rupture in the second or third trimester, resulting in intraperitoneal hemorrhage, a life-threatening emergency
• Abnormalities of placentation


  • Circumvallate placenta
  • Placenta previa
  • Placenta accreta
  • Placenta increta
  • Placenta percreta
  • Vasa previa
  • Velamentous placenta
  • Succenturiate placenta
• Predisposing factors for placenta previa

  • Prior cesarean section and uterine surgery
  • Multiparity
  • Multiple gestation
  • Erythroblastosis
  • Smoking
  • History of placenta previa
  • Increasing maternal age
• Placenta previa occurs in approximately 0.5% of pregnancies (1:200 births) and accounts for nearly 20% of all antepartum hemorrhage
• Placenta previa can also be complicated by an associated placenta accreta in approximately 5% of cases
• The risk of placenta accreta is increased in women with placenta previa in the setting of prior cesarean delivery
• Women who at 20 weeks have a low-lying placenta that does not overlie the internal os will not have a placenta previa at term and need no further sonographic examinations for placental location
• Sentinel bleed


  First episode of bleeding in placenta previa, usually occurs after 28 weeks of gestation
• Vaginal examination is contraindicated in placenta previa because the digital examination can cause further separation of the placenta and trigger catastrophic hemorrhage
• Transvaginal sonography


  Accurate and superior method for the diagnosis of placenta previa compared to transabdominal sonography
• Transvaginal sonography for diagnosis of placenta previa

  • Sensitivity greater than 95%
  • Accurate diagnosis of placenta previa
  • Does not lead to an increase in bleeding
• Transabdominal sonography lacks precision in diagnosing placenta previa
• Transvaginal sonography is superior to transabdominal sonography for diagnosis of placenta previa
• Reasons for superiority of transvaginal sonography

  • Bladder filling can cause overdiagnosis of placenta previa with transabdominal
  • Vaginal probes are closer to the region of interest and obtain higher resolution images
  • Internal cervical os and lower placental edge frequently cannot be imaged adequately by transabdominal approach
  • Fetal head may obscure views of lower placental edge with transabdominal approach
• Incidence of placenta previa is lower when using transvaginal sonography compared to transabdominal sonography
• Transvaginal sonography is safe and does not lead to an increase in bleeding
• Translabial sonography is superior to transabdominal sonography but transvaginal sonography should be the imaging modality of choice
• Placenta accreta should be suspected in women with placenta previa and history of cesarean delivery or other uterine surgery
• Management of placenta previa

  1. Strict pelvic rest and modified bed rest

  2. Inpatient or outpatient management

  3. Delivery by cesarean section for complete or partial placenta previa

  4. Vaginal delivery allowed for low-lying placenta or marginal previa
• Postpartum hemorrhage risk in women with placenta extending into lower uterine segment who have vaginal delivery
• Management of vaginal bleeding with suspected placenta previa/accreta

  1. Stabilize patient

  2. Prepare for catastrophic hemorrhage

  3. Prepare for preterm delivery
• Management of suspected placenta accreta/increta/percreta

  • Plan for total abdominal hysterectomy
  • Schedule delivery at 34-37 weeks
  • Have backup resources available
• Placental abruption


  Premature separation of the normally implanted placenta from the uterine wall, resulting in hemorrhage