12.3 Antepartum Hemorrhage & Uterine Rupture

12.3 Antepartum Hemorrhage & Uterine Rupture

Absolute Life-Saving Rule: In any pregnant woman presenting with third-trimester vaginal bleeding, never perform a digital vaginal examination (VE) until placenta previa has been conclusively excluded by obstetric ultrasound. A single digital examination into a placenta previa can shear placental vessels, triggering massive exsanguination that can cause maternal death within minutes.

Antepartum hemorrhage (APH) is defined as bleeding from or into the genital tract from 28 weeks of gestation (the threshold of fetal viability in Kenya and resource-limited settings) until the complete delivery of the baby. It complicates 3% to 5% of all pregnancies and constitutes an acute obstetric emergency. The three major life-threatening conditions demanding immediate clinical distinction are Placenta Previa, Abruptio Placentae, and Uterine Rupture.

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1. Placenta Previa: Clinical Profile & Management

Definition and Anatomical Classification

Placenta previa occurs when the placenta implants entirely or partially within the lower uterine segment, directly overlying or dangerously adjacent to the internal cervical os:

• Low-Lying Placenta: The placental edge lies in the lower uterine segment within 2 cm of the internal cervical os, but does not cover it.
• Marginal Previa: The placental edge reaches the margin of the internal os without covering it.
• Partial Previa: The placenta partially covers the internal cervical os.
• Complete (Major) Previa: The placenta completely bridges and covers the internal cervical os. Even with complete cervical dilatation, the placenta obstructs the birth canal.

Risk Factors

• Previous Cesarean section or uterine scar (e.g., myomectomy). A prior scar damages the endometrium, promoting low blastocyst implantation; it dramatically elevates the co-existent risk of Placenta Accreta Spectrum (PAS).
• High parity and advanced maternal age (> 35 years).
• Multiple gestation (larger surface area of placental tissue).
• History of uterine curettage or manual removal of the placenta.
• Cigarette smoking (compensatory placental hypertrophy secondary to carbon monoxide hypoxemia).

Clinical Presentation: The Classic Triad

1. Painless, Bright Red Bleeding: Sudden onset of vaginal bleeding occurring without painful contractions. The initial 'warning bleed' often presents around 30 to 34 weeks, is self-limiting, but recurs with greater severity as the lower segment stretches and shears.
2. Soft, Non-Tender, Relaxed Uterus: Uterine tone is completely normal; between bleeding episodes, the uterus is soft, non-tender, and non-irritable.
3. Abnormal Fetal Presentation & High Station: Because the lower pole of the uterus is occupied by placental tissue, the fetal presenting part cannot engage in the pelvic brim (high, mobile fetal head, or malpresentations such as transverse lie, oblique lie, or breech). Fetal heart sounds are typically normal and reassuring unless profound maternal shock supervenes.

Diagnostic Contraindication & Imaging

• STRICT CONTRAINDICATION: Digital vaginal examination is strictly prohibited. Even gentle palpation through the vaginal fornices can cause massive, uncontrollable hemorrhage.
• Definitive Diagnostic Tool: Obstetric Ultrasonography. Transabdominal ultrasound identifies placental localization with high accuracy. If equivocal, transvaginal ultrasound (TVS) performed by an experienced clinician is safe and provides superior visualization of the internal os.

Management Strategy

• Expectant (Conservative / MacAfee Protocol): Indicated if bleeding is mild, maternal hemodynamics are stable, gestational age is < 37 weeks, and fetus is reassuring. Involves strict bed rest, hospital admission, maternal blood crossmatched (at least 2 units PRBCs kept on standby), and intramuscular Dexamethasone (6 mg IM 12-hourly for 4 doses) to accelerate fetal lung maturation. Tocolysis is generally avoided or used with extreme caution.
• Definitive Operative Delivery: Elective Cesarean section is planned at 36 to 37 weeks for complete/major placenta previa. If torrential hemorrhage occurs at any gestational age, immediate emergency Category 1 Cesarean section must be performed irrespective of fetal maturity.

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2. Abruptio Placentae: Clinical Profile & Management

Pathophysiology & Classification

Abruptio placentae is the premature detachment of a normally situated placenta from the uterine myometrium prior to the delivery of the fetus:

• Revealed (External) Abruption (80%): Blood tracks down between the fetal membranes and decidua and escapes through the cervix; visible external vaginal bleeding.
• Concealed (Internal) Abruption (20%): Blood collects behind the placenta forming a massive retroplacental hematoma without escaping externally. This is far more dangerous, as the external blood loss is zero or minimal, leading clinicians to dangerously underestimate hypovolemic shock.

                               [DECIDUAL SPIRAL ARTERIOLAR RUPTURE]
                     (Driven by Maternal Vasospasm / Chronic Hypertension / Trauma)
                                                │
                                                ▼
                              [RETROPLACENTAL HEMATOMA FORMATION]
                                                │
                                                ▼
                      [Progressive Shearing & Decidual Separation]
                                                │
                   ┌────────────────────────────┴────────────────────────────┐
                   ▼                                                         ▼
      [REVEALED ABRUPTION (~80%)]                               [CONCEALED ABRUPTION (~20%)]
  • Blood tracks down between membranes                     • Retroplacental hematoma remains trapped
  • Dark, non-clotting vaginal bleeding                     • Fundus rises progressively
  • Visible blood reflects true loss                        • Severe pain; shock disproportionate to bleed
                   │                                                         │
                   └────────────────────────────┬────────────────────────────┘
                                                │
                                                ▼
                             [MASSIVE TISSUE FACTOR RELEASE]
                                                │
                                                ▼
                     [DISSEMINATED INTRAVASCULAR COAGULATION (DIC)]
                    (Severe Hypofibrinogenemia, Bleeding from Puncture Sites)
                                                │
                                                ▼
                      [COUVELAIRE UTERUS / UTEROPLACENTAL APOPLEXY]
               (Myometrial blood extravasation -> Atony -> Intractable PPH)

Risk Factors

• Maternal Hypertensive Disorders: Chronic hypertension, gestational hypertension, pre-eclampsia, and eclampsia account for > 50% of severe abruptions.
• Sudden uterine decompression (rapid decompression following rupture of membranes in polyhydramnios or delivery of first twin).
• Blunt abdominal trauma (motor vehicle accidents, physical assault).
• Grand multiparity and advanced maternal age.
• History of previous abruption (recurrence risk 10–15%).

Clinical Presentation: Cardinal Signs

1. Severe, Continuous Abdominal or Back Pain: Pain is unrelenting, deep, and knife-like, distinct from the intermittent colic of labor contractions.
2. Dark, Non-Clotting Vaginal Bleeding: Blood is characteristically dark venous or port-wine colored. In concealed abruption, external bleeding may be completely absent.
3. The 'Woody' Board-Like Hypertonic Uterus: On palpation, the uterus is persistently hypertonic, unyielding, board-like hard, and exquisitely tender. Fetal parts are extremely difficult or impossible to palpate through the tense myometrial wall.
4. Fetal Distress or Demise: Fetal heart monitoring demonstrates recurrent late decelerations, severe bradycardia, or absent fetal heart tones (fetal demise occurs in 30% to 50% of severe abruptions).
5. Maternal Hypovolemic Shock Disproportionate to Bleeding: In concealed abruption, the patient presents with pallor, diaphoresis, tachycardia, and severe hypotension despite negligible external vaginal bleed.

Severe Complications of Abruptio Placentae

• Disseminated Intravascular Coagulation (DIC): Driven by the systemic absorption of thromboplastin from the retroplacental clot. Evaluated at the bedside using the Bedside Clotting Test: 2 to 5 mL of maternal blood drawn into a dry, clean glass test tube. Normal blood clots solidly within 7 to 10 minutes. Blood that remains completely liquid or forms a friable clot that dissolves after 10 minutes confirms consumptive coagulopathy.
• Couvelaire Uterus (Uteroplacental Apoplexy): Widespread extravasation of blood into the myometrium beneath the uterine serosa, giving the uterus a purplish, mottled, ecchymotic appearance during laparotomy. Impairs myometrial contractility and predisposes to intractable postpartum atony.
• Acute Kidney Injury (AKI): Secondary to prolonged hypovolemic renal cortical necrosis.

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3. Comprehensive Differential Diagnosis of Major APH

+---------------------------------------------------------------------------------------------------------+
|                         DIFFERENTIAL DIAGNOSIS: PLACENTA PREVIA VS. ABRUPTION VS. RUPTURE               |
+-------------------+-----------------------+---------------------------+---------------------------------+
| CLINICAL FEATURE  | PLACENTA PREVIA       | ABRUPTIO PLACENTAE        | UTERINE RUPTURE                 |
+-------------------+-----------------------+---------------------------+---------------------------------+
| Pain Quality      | Completely PAINLESS   | Continuous, SEVERE pain   | Sudden, TEARING, agonizing pain |
+-------------------+-----------------------+---------------------------+---------------------------------+
| Bleeding Nature   | Recurrent, BRIGHT RED | Dark, venous, non-clotting| Variable; often concealed       |
+-------------------+-----------------------+---------------------------+---------------------------------+
| Uterine Tone      | Soft, non-tender      | 'Woody', board-like, tense| Contractions CEASE abruptly     |
+-------------------+-----------------------+---------------------------+---------------------------------+
| Palpation         | Fetus easily felt;    | Fetal parts difficult     | Fetal parts felt SUPERFICIALLY  |
|                   | high presenting part  | to palpate                | under maternal abdominal skin   |
+-------------------+-----------------------+---------------------------+---------------------------------+
| Fetal Heart Rate  | Usually normal        | Severe distress or absent | Severe bradycardia or ABSENT    |
+-------------------+-----------------------+---------------------------+---------------------------------+
| Shock vs Bleeding | Shock proportional    | Shock OUT OF PROPORTION   | Profound, rapid collapse;       |
|                   | to visible blood loss | to visible blood loss     | hypovolemic peritonitis         |
+-------------------+-----------------------+---------------------------+---------------------------------+
| Digital Vaginal Ex| STRICTLY FORBIDDEN!   | Cautious examination only | Contraindicated; station recedes|
+-------------------+-----------------------+---------------------------+---------------------------------+

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4. Uterine Rupture: Catastrophic Disruption

Etiology and Risk Factors

Uterine rupture is the anatomical separation of all layers of the myometrium, including the overlying visceral peritoneum, during pregnancy or labor. It is one of the most catastrophic obstetric disasters, carrying a perinatal mortality rate exceeding 80% and significant maternal mortality:

• Previous Uterine Scar (Predominant Cause): Prior lower-segment Cesarean section (0.5–1% rupture risk), prior classical (vertical) Cesarean section (4–10% rupture risk, often ruptures before labor onset), or prior transmural myomectomy.
• Obstructed Labor & Cephalopelvic Disproportion (CPD): Excessive, unyielding myometrial contraction against a mechanical obstruction in an unscarred uterus.
• Injudicious Use of Uterotonics: Misuse of high-dose oxytocin or misoprostol in labor, particularly in women with prior scars or grand multiparas.
• Aggressive Operative Vaginal Delivery / Fundal Pressure: Destructive maneuvers, version, or excessive fundal pushing.

Cardinal Clinical Manifestations

• Sudden Tearing Abdominal Pain: Occurs at the height of a strong labor contraction; the patient often cries out that 'something has ripped' inside her.
• Immediate Cessation of Uterine Contractions: The hyperactive, tetanic uterine contractions abruptly cease as the myometrial wall tears open.
• Loss of Fetal Station (Recession of Presenting Part): A fetal head that was deeply engaged in the pelvis (e.g., station 0 or +1) suddenly floats upward and recedes out of reach of the examining fingers.
• Superficially Palpable Fetal Parts: The fetus is extruded through the uterine rupture into the maternal peritoneal cavity; fetal extremities and contours become strikingly distinct and palpable immediately beneath the maternal abdominal wall, alongside a small, hard, contracted empty uterine corpus.
• Profound Maternal Collapse & Hematuria: Sudden hypotension, unrecordable blood pressure, rapid thready pulse, and gross hematuria (indicates anterior rupture tearing directly into the bladder base).

Emergency Resuscitation and Surgical Protocol

• Simultaneous Immediate Action: Do not wait for ultrasound! Call for help, initiate rapid volume resuscitation through two 14G/16G IV lines with warm crystalloids, crossmatch 4 to 6 units of whole blood or PRBCs, and transfer the patient directly to the operating theater.
• Exploratory Laparotomy: Perform a rapid midline infraumbilical incision. Deliver the extruded fetus and placenta from the peritoneal cavity; clamp bleeding margins.
• Surgical Decision:
  • Uterine Repair: Feasible if the tear is low, transverse, clean-edged, the patient is hemodynamically stabilized, and future fertility is strongly desired.
  • Subtotal or Total Hysterectomy: Mandatory if the rupture is extensive, jagged, involves the broad ligament, tears into the uterine vessels, or if the patient is in extremis with disseminated coagulopathy.