Study Notes on Abruptio Placentae

Abruptio Placentae

Definition

  • Abruptio Placentae: The premature separation of the normally implanted placenta from the uterine wall occurring after the 20th week of gestation and before the second stage of labor.

Obstetric Hemorrhage

  • Significance: Ranks as the leading cause of maternal mortality, accounting for 25-50% of maternal deaths.

Abruption and Placenta Previa: Epidemiology & Causes

  • Incidence:

    • 4% of women may develop antepartum hemorrhage (APH).

    • Causes of APH include:

    • Placenta previa: 1 in 200 pregnancies.

    • Placental abruption: 1 in 100 pregnancies.

    • Uterine rupture: less than 1% in scarred uterus.

    • Vasa previa: 1 in 2000-3000 pregnancies.

  • Local causes:

    • Cervical polyp

    • Bloody show

    • Cervicitis or cervical ectropion

    • Cervical cancer

Epidemiology of Abruption

  • Occurrence: 1-2% of pregnancies.

  • Role in bleeding: Accounting for 20% of all third-trimester bleeders.

  • Recurrence risk: 10% in a first pregnancy; 25% in a second pregnancy.

  • Impact on mortality:

    • Perinatal mortality of 15-20%.

    • Maternal mortality of 2-5%.

Risk Factors for Abruptio Placentae

  • Smoking or substance abuse (e.g., cocaine).

  • History of previous abruption.

  • High birth order.

  • Advancing maternal age.

  • Poor socioeconomic conditions.

  • Malnutrition.

  • Placental insufficiency.

Evidence for Risk Factors

  • Maternal age and parity: 1.1-3.7 RR (Relative Risk)

  • Cigarette smoking: 1.4-2.5 RR

  • Cocaine and drug use: 5.0-10.0 RR

  • Multiple gestations: 1.5-3.0 RR

  • Chronic hypertension: 1.8-5.1 RR

  • Preeclampsia: 0.4-4.5 RR

  • Oligohydramnios: 2.5-10.0 RR

  • Chorioamnionitis: 2.0-2.5 RR

  • Dietary/nutritional deficiency: 0.9-2.0 RR

  • Male fetus: 0.9-1.3 RR

Etiology of Abruptio Placentae

  • Hypertension in Pregnancy: Spasms of utero-placental blood vessels leading to anoxic endothelial damage and rupture of vessels, or extravasation of blood in the decidua basalis.

  • Trauma: Includes external cephalic version, road traffic accidents (RTA), and needle puncture during amniocentesis.

  • Sudden uterine decompression: Occurs during delivery of first twins, sudden escape of liquor amnii in hydramnios, and premature rupture of membranes.

  • Other factors:

    • Short umbilical cord

    • Supine hypotension syndrome

    • Placental anomalies

    • Thrombophilias

Pathogenesis

  • Hemorrhage into the decidua basalis initiates placental separation.

  • Formations of decidual hematomas lead to degeneration and necrosis of the decidua basalis and adjacent placental tissue.

Classification of Abruptio Placentae

  1. Extent of Separation: Partial vs complete.

  2. Location of Separation: Marginal vs central.

  3. Clinical Presentation: Revealed, concealed, and mixed types.

  4. Clinical Severity: Mild, moderate, and severe classifications.

Clinical Severity Grades

  • Grade 0: No clinical features; diagnosis after placental examination.

  • Grade 1 (Mild): 40% of cases; no to mild vaginal bleeding, slightly tender uterus, stable vital signs, no coagulopathy, no fetal distress.

  • Grade 2 (Moderate): 45% of cases; moderate vaginal bleeding, tender uterus, maternal tachycardia, possible fetal distress, low fibrinogen levels.

  • Grade 3 (Severe): 15% of cases; heavy vaginal bleeding, severe uterine pain, maternal shock, coagulopathy, likely fetal death.

Clinical Manifestations of Hemorrhage

  • Concealed Hemorrhage: Accumulation of blood behind the placenta.

  • Revealed Hemorrhage: Blood escapes through the cervix.

  • Couvelaire Uterus: Blood infiltration through myometrium.

Complications of Abruptio Placentae

  • Maternal Complications: Shock, renal failure, disseminated intravascular coagulopathy (DIC), postpartum hemorrhage (PPH), Sheehan syndrome, puerperal sepsis.

  • Fetal Complications: Fetal distress/demise, hypoxic brain injury, intrauterine growth restriction (IUGR), neonatal anemia, congenital malformations.

Diagnosis

  • Based on physical examination, history, and ultrasound findings.

  • The triad of external bleeding through the cervical os, uterine or back pain, and fetal distress indicates high suspicion for abruption.

Laboratory Tests for Diagnosis

  • Complete Blood Count (CBC).

  • Blood type and screen.

  • Urinalysis.

  • Liver function tests.

  • Renal function tests.

  • Prothrombin time and activated partial thromboplastin time (aPTT).

  • Fibrinogen levels.

Management of Abruptio Placentae

  • General Management: Depends on maternal condition and gestational age of fetus.

  • Delivery: Resuscitation with fluids, monitoring maternal vitals, and continuous fetal heart rate (FHR) monitoring.

  • Vaginal Delivery Considerations: Limited placental abruption with reassuring fetal heart sounds. Can proceed with vaginal delivery if conditions are favorable.

  • Cesarean Section Indications: Severe bleeding, poor progress, transverse lie, or when fetal condition necessitates emergency delivery.

  • Expectant Management: Series of assessments to monitor non-laboring patients with stable conditions, particularly in preterm cases.

    • Administer steroids for fetal lung maturity if preterm.

Conclusion

  • Abruptio Placentae presents significant maternal and fetal risks, and its understanding requires thorough assessment and management for better outcomes. The management goal is to resuscitate and prolong pregnancy when feasible or proceed with immediate delivery for maternal or fetal indications if necessary.