Antepartum hemorrhage

Antepartum hemorrhage is a serious complication of pregnancy occurring within the third trimester. It is associated with significant maternal and fetal morbidity and mortality. Common causes of antepartum hemorrhage are bloody show associated with labor, miscarriage, placental previa, and placental abruption. Rare causes include vasa previa and uterine rupture. Symptoms of placental abruption typically include lower abdominal pain, vaginal bleeding, and a rigid uterus. Placenta previa and vasa previa on the other hand typically manifest prior to rupture of membranes or after rupture of membranes respectively, with painless vaginal bleeding and fetal distress. Uterine rupture, which occurs during labor, is discussed in a separate learning card. In cases of severe hemorrhage, patients may present with signs of hypovolemic shock. Fetal symptoms include signs of fetal stress, such as decelerations on heart monitoring and decreased fetal movements. The diagnosis is primarily clinical and is confirmed via transabdominal or transvaginal ultrasound. The treatment approach depends on maternal symptoms and fetal vitality. A conservative approach with continuous monitoring is advised for asymptomatic patients carrying a healthy fetus, while an emergency cesarean section is indicated in patients with acute symptoms and a live, distressed fetus.

Definition

• The partial or complete separation of the placenta from the uterus prior to delivery. Subsequent hemorrhage occurs from both maternal and fetal vessels.

Epidemiology

• Incidence: ∼ 0.2–1% of pregnancies
• Occurs most often in the third trimester
• The recurrence rate in subsequent pregnancies is 3–15%.

Etiology

• Predisposing factors
  • Vascular changes
    • Hypertension (most common cause)
    • Preeclampsia/eclampsia
  • (Abdominal) trauma; (up to 10% of cases): car accidents, falls, iatrogenic (e.g., post-amniocentesis)
  • Sudden decrease in intrauterine pressure
  • Previous abruption, chorioamnionitis, prolonged rupture of membranes, short umbilical cord
  • Maternal age: < 20 years and > 35 years
  • Alcohol and cigarette consumption, cocaine use

Clinical features

Following placental separation of more than 30%, there is a sudden onset of the following symptoms:

• Continuous, dark, vaginal bleeding (revealed abruptio placentae)
• In ∼ 20% of cases, the hemorrhage is mainly retroplacental; vaginal bleeding does not occur (concealed abruptio placentae)
• Abdominal pain or back pain , uterine tenderness
• Hypertonic contractions (rigid uterus), premature labor
• Fetal distress (60% of cases)
  • Possible diminished or absent fetal movement
  • Decelerations seen on fetal heart monitor
• Vaginal exam contraindicated: may worsen bleeding!

In cases of retroplacental hemorrhage, patients may present with signs of hypovolemic shock without evident vaginal bleeding!

Diagnostics

Placental abruption is a clinical diagnosis

• Ultrasound (transabdominal, transvaginal): only 25% sensitivity!
  • Presentation of the placental position and a possible retroplacental hematoma
  • Monitoring vital signs of the fetus (heartbeat, fetal movement)
  • To rule out placenta previa in unclear cases
• Fetal heart rate monitoring (see “Clinical features” above)
• Laboratory tests: CBC, coagulation factors

Rapid diagnosis and immediate treatment are vital for the survival of both mother and child!

Treatment

General approach

• Hemodynamic control: monitor vital signs, maintain airways, volume resuscitation, type and crossmatch blood
• Correct coagulopathy if necessary
• RhD prophylaxis in RhD negative mothers
• See also peripartum hemorrhage.

Specific approach according to severity

• Normal fetal findings and a hemodynamically stable mother
  • Observation, bed rest, regular control
  • Up to the 34^th week of pregnancy
    • Fetal lung maturity induction with corticosteroids (e.g., betamethasone)
    • If necessary, tocolysis (e.g., nifedipine, β2-adrenergic agonist)
    • Aim for a normal delivery
  • 34^th to 36^th week
    • Active uterine contractions present: vaginal delivery
    • No contractions + no signs of fetal distress + bleeding has stopped: expectant management and observation
  • All pregnancies are delivered if acute abruption occurs after 36^th weeks.
• In acute symptoms and a live fetus
  • Emergency cesarean section independent of gestational age unless vaginal delivery is impending
• In acute symptoms and intrauterine fetal death
  • Induction of vaginal delivery through pharmacologic uterine contraction inducers and opening of the amniotic sac
  • An emergency cesarean section must be performed if there is a maternal risk; due to severe bleeding or slow progression of the birthing process, even in cases of intrauterine fetal death.

Complications

• Intrauterine fetal death (occurs in ∼ 12% of cases)
• Maternal DIC and hypovolemic shock
• Couvelaire uterus
  • Retroplacental hemorrhage may extend through the uterus into the peritoneum.
  • The myometrium is weakened, with possible subsequent uterine rupture during contractions.

References:^{[1][2][3][4][5]}

Definition

• Presence of the placenta in lower uterine segment; , which might lead to partial or full obstruction of the neck of the uterus with high risk of hemorrhage (rupture of placental vessels) and birth complications

Epidemiology

• ∼ 0.3–0.5% of all pregnancies

Etiology

• Risk factors
  • Maternal age > 35 years, multiparity, short intervals between pregnancies
  • Previous curettage or cesarean section
  • Previous placenta previa, previous/recurrent abortion

Classification

Placenta previa is classified based on how much of the cervical orifice is covered by the placenta.

• Low-lying placenta: : lower edge of the placenta lies less than 2 cm from the internal cervical os
• Marginal previa: placenta reaches the internal cervical os
• Partial previa: placenta partially covers the internal cervical os
• Complete previa (total previa): placenta completely covers the internal cervical os

Clinical features

• Sudden, painless, bright red vaginal bleeding
• Usually occurs during the 3^rd trimester (before rupture of the membranes), stops spontaneously after 1–2 hours, and recurs during birth
• Often causes preterm delivery (∼ 45% of cases)
• Soft, nontender uterus
• Usually no fetal distress

In contrast to placental abruption, bleeding in patients with placenta previa is painless!

Diagnostics

• Transvaginal ultrasound to assess the position of the placenta
• Digital vaginal examinations are contraindicated in cases of hemorrhage of unknown cause!

Treatment

• Approach
  • Gestational age < 37 weeks
    • No active bleeding AND no evidence of fetal distress: expectant management
    • Active bleeding OR evidence of fetal distress: immediate delivery
  • Gestational age > 37 weeks: immediate delivery
• Expectant mangament
  • Hospitalization and observation for 48 hours
  • If gestational age < 34 weeks: fetal lung maturity induction with corticosteroids (e.g., betamethasone)
  • If mild uterine contractions are present: tocolysis with magnesium sulfate may be performed (especially if the fetus is extremely premature)
• Route of delivery
  • Lower segment cesarean section is almost always preferred; ; ideally scheduled at 36–37 weeks gestation
  • Induction of labor and/or vaginal delivery may be performed in the operating room if the mother is hemodynamically stable, fetal cardiac status is reassuring, and the placenta lies > 2 cm away from the internal os on ultrasonography

Vaginal delivery should never be attempted outside the operating room in a patient with placenta previa

References:^{[6][7][8][9][10][11][12]}