High-Risk Obstetric Emergencies: A Clinical Guide for PA Students
Preterm Labor
Definition and Diagnosis
Preterm labor is defined as regular uterine contractions with cervical change occurring before 37 weeks of gestation. 1
- Diagnostic criteria include:
Risk Factors
- Maternal factors: Previous preterm birth, multiple gestations, short cervical length (<25mm), uterine anomalies 2
- Pregnancy complications: Infection (chorioamnionitis), placental abruption, PPROM 2
- Medical conditions: Hypertension, diabetes, systemic lupus erythematosus 1
- Behavioral factors: Smoking >10 cigarettes/day, substance abuse 1
Management Algorithm
For threatened preterm labor <34 weeks with intact membranes:
- Tocolysis: Use to delay delivery 48 hours for corticosteroid administration 2
- Corticosteroids: Betamethasone 12mg IM q24h x2 doses or dexamethasone 6mg IM q12h x4 doses for fetal lung maturity if delivery anticipated <35 weeks 3
- Magnesium sulfate: Administer for neuroprotection if delivery expected <32 weeks 3
- Antibiotics: Only indicated if PPROM present (see below) 1
For preterm labor ≥34 weeks:
- Proceed with delivery as neonatal outcomes are favorable 2
Preterm Prelabor Rupture of Membranes (PPROM)
Definition and Incidence
PPROM is membrane rupture before labor onset occurring before 37 weeks of gestation, complicating <1% of pregnancies but causing one-third of all preterm births. 1, 4
Diagnostic Approach
Diagnosis requires sterile speculum examination—never perform digital cervical exam until labor is established to reduce infection risk. 4, 5
- Pooling test: Visualize amniotic fluid pooling in posterior vaginal fornix 5
- Nitrazine test: pH >6.5 turns paper blue (90% sensitivity) 4, 5
- Ferning test: Microscopic crystallization pattern on dried fluid 4, 5
- Combination accuracy: Two positive tests = 93.1% diagnostic accuracy 4
- Modern tests: AmniSure or Actim tests for equivocal cases 5
Gestational Age-Based Management
For previable/periviable PPROM (20 0/7 to 23 6/7 weeks):
- All patients must receive individualized counseling about maternal risks (sepsis, hemorrhage) and fetal outcomes (5-6% survival <23 weeks with 98-100% severe morbidity among survivors). 1
- Both abortion care and expectant management should be offered; abortion care must be available to all patients. 1
- Antibiotics can be considered but are not mandatory at this gestational age 1
For PPROM 24 0/7 to 31 6/7 weeks:
- Expectant management with hospitalization is standard. 2
- Antibiotics are mandatory: 7-day course reduces neonatal morbidity 1, 2
- Ampicillin 2g IV q6h + erythromycin 250mg IV q6h x48h, then amoxicillin 250mg PO q8h + erythromycin base 333mg PO q8h x5 days 2
- Corticosteroids: Administer for fetal lung maturity 1, 3
- Magnesium sulfate: Give for neuroprotection if delivery imminent 1, 3
- Monitor for: Chorioamnionitis (fever, maternal/fetal tachycardia, uterine tenderness, purulent discharge), placental abruption, cord compression 2
For PPROM 32 0/7 to 33 6/7 weeks:
- Consider delivery versus expectant management based on lung maturity assessment 2
For PPROM ≥34 weeks:
- Proceed with delivery as benefits clearly outweigh risks. 2
Contraindications to Expectant Management
Immediate delivery indicated for:
Placenta Previa
Definition and Classification
Placenta previa is placental implantation that covers or lies within 2cm of the internal cervical os.
- Complete previa: Placenta completely covers internal os
- Marginal previa: Placental edge within 2cm of os but doesn't cover it
- Low-lying placenta: Placental edge within 2cm of os on transvaginal ultrasound
Risk Factors
- Previous cesarean delivery (most significant risk factor)
- Advanced maternal age (>35 years) 1
- Multiparity (≥3 previous births) 1
- Multiple gestation 1
- Previous uterine surgery or curettage
- Smoking 1
Clinical Presentation
Classic presentation is painless vaginal bleeding in the second or third trimester.
- Bleeding typically occurs after 20 weeks
- May be provoked by intercourse or contractions
- Never perform digital cervical examination if previa suspected—can precipitate massive hemorrhage
Diagnostic Approach
- Transvaginal ultrasound is gold standard and safe: Provides accurate placental localization
- Transabdominal ultrasound for initial screening
- MRI reserved for suspected placenta accreta spectrum
Management Strategy
For asymptomatic previa diagnosed <28 weeks:
- Pelvic rest (no intercourse, no vaginal exams)
- Activity modification
- Repeat ultrasound at 28 and 32 weeks (many resolve with lower uterine segment development)
For bleeding episodes:
- Hospitalize for active bleeding
- Type and crossmatch blood
- Large-bore IV access
- Continuous fetal monitoring
- Corticosteroids if <34 weeks 3
- Consider hospitalization until delivery for recurrent bleeding
Delivery planning:
- Scheduled cesarean delivery at 36-37 weeks for persistent previa
- Earlier delivery for uncontrolled bleeding or non-reassuring fetal status
- Prepare for potential massive hemorrhage and placenta accreta spectrum
- Multidisciplinary team including anesthesia, blood bank, possible gynecologic oncology
Placental Abruption
Definition and Severity
Placental abruption is premature separation of a normally implanted placenta from the uterine wall before delivery, occurring in 0.5-1% of pregnancies.
Risk Factors
- Hypertensive disorders: Most significant modifiable risk factor 1
- Previous abruption (10-25% recurrence risk)
- Maternal trauma (motor vehicle accident, domestic violence)
- Cocaine or methamphetamine use
- Cigarette smoking 1
- Advanced maternal age 1
- Multiparity 1
- Preterm PPROM 1
- Thrombophilias 1
Clinical Presentation
Classic triad (only present in 50% of cases):
- Vaginal bleeding (80% of cases—may be concealed in 20%)
- Abdominal/back pain with uterine tenderness
- Uterine contractions/hypertonus
Additional findings:
- Non-reassuring fetal heart rate patterns
- Maternal hemodynamic instability (tachycardia, hypotension)
- Coagulopathy in severe cases (DIC develops in 10%)
Diagnostic Approach
Diagnosis is primarily clinical—ultrasound has poor sensitivity (25-50%) and should not delay management.
- Continuous fetal monitoring mandatory
- Maternal labs: CBC, type and crossmatch, coagulation studies (PT, aPTT, fibrinogen, D-dimer), Kleihauer-Betke if Rh-negative
- Ultrasound to assess fetal viability and rule out previa
Management Based on Severity
Mild abruption (no maternal/fetal compromise, <1/3 placental separation):
- Hospitalization with continuous monitoring
- Corticosteroids if <34 weeks 3
- Expectant management may be considered if stable
Moderate to severe abruption:
- Immediate delivery is indicated regardless of gestational age 1
- Aggressive fluid resuscitation with crystalloid
- Transfuse PRBCs to maintain hemoglobin >7-8 g/dL
- Correct coagulopathy: FFP for INR >1.5, cryoprecipitate for fibrinogen <200 mg/dL, platelets for count <50,000/mm³ 3
- Vaginal delivery acceptable if maternal/fetal status stable and labor progressing
- Cesarean delivery for non-reassuring fetal status, failed induction, or maternal instability
Fetal demise with abruption:
- Vaginal delivery preferred unless maternal indication for cesarean
- Monitor closely for DIC development
Preeclampsia/Eclampsia
Definitions
Preeclampsia is new-onset hypertension (≥140/90 mmHg) after 20 weeks gestation with proteinuria or end-organ dysfunction. 3, 6
Severe features include:
- Blood pressure ≥160/110 mmHg 3
- Thrombocytopenia (<100,000/mm³) 3
- Elevated liver enzymes (AST/ALT >2x normal) 3
- Renal insufficiency (creatinine >1.1 mg/dL or doubling of baseline) 3
- Pulmonary edema 3
- New-onset cerebral or visual symptoms 3
Eclampsia is new-onset grand mal seizures in a woman with preeclampsia that cannot be attributed to other causes. 3
Atypical Presentations to Recognize
Preeclampsia can occur without classic hypertension and proteinuria—15% of HELLP cases have normal blood pressure. 7, 6
- Before 20 weeks: Consider molar pregnancy, antiphospholipid syndrome 6
- Beyond 48 hours postpartum: Late postpartum preeclampsia/eclampsia occurs in up to 25% of cases 6
- Isolated symptoms: Severe headache, visual changes, or epigastric pain may precede hypertension 6
Risk Factors
- Nulliparity or new paternity
- Previous preeclampsia (15-25% recurrence)
- Chronic hypertension 1
- Pregestational diabetes
- Renal disease
- Autoimmune disease (SLE, antiphospholipid syndrome) 1
- Multiple gestation 1
- Obesity (BMI >30) 1
- Maternal age >35 or <20 years 1
- Family history of preeclampsia
Diagnostic Workup
Essential laboratory assessment includes: 3, 8
- Complete blood count with platelet count
- Comprehensive metabolic panel (creatinine, liver enzymes)
- Urinalysis with protein quantification (24-hour urine or protein/creatinine ratio)
- Coagulation studies if platelets <100,000/mm³
- LDH and peripheral smear if hemolysis suspected
Management of Preeclampsia Without Severe Features
Antepartum management:
- Outpatient management acceptable with close surveillance
- Blood pressure checks twice weekly
- Weekly labs (CBC, liver enzymes, creatinine)
- Fetal surveillance (NST, AFI) twice weekly starting at diagnosis
- Patient education on warning symptoms
Antihypertensive therapy:
- Initiate oral therapy for blood pressure 140-159/90-109 mmHg using labetalol, nifedipine, or methyldopa 3
- Target blood pressure 130-150/80-100 mmHg
Delivery timing:
- Deliver at 37 weeks for preeclampsia without severe features 3
Management of Preeclampsia With Severe Features
Immediate interventions:
- Hospitalization mandatory 3
- Severe hypertension (≥160/110 mmHg) requires urgent treatment within 30-60 minutes 3
Seizure prophylaxis:
- Magnesium sulfate mandatory for all severe preeclampsia and during labor/24 hours postpartum 3
- Loading dose: 4-6g IV over 15-20 minutes
- Maintenance: 2g/hour continuous infusion 3
- Monitor: Deep tendon reflexes, respiratory rate >12/min, urine output >25 mL/hour
- Antidote: Calcium gluconate 1g IV for magnesium toxicity
Delivery timing:
- Deliver at 34 weeks for severe preeclampsia 3
- Immediate delivery indicated for: 3
- Eclampsia
- Pulmonary edema
- Placental abruption
- Non-reassuring fetal status
- Persistent severe symptoms despite treatment
Expectant management <34 weeks (highly selective):
- Only if maternal/fetal status stable
- Corticosteroids for fetal lung maturity 3
- Continuous inpatient monitoring
- Daily labs and fetal surveillance
Management of Eclampsia
Acute seizure management:
- Magnesium sulfate is first-line: 4-6g IV bolus over 5 minutes, then 2g/hour maintenance 3
- Protect airway, supplemental oxygen
- Left lateral positioning
- If seizures persist: Additional 2g magnesium bolus or consider lorazepam 2-4mg IV
- Deliver after maternal stabilization regardless of gestational age 3
Postpartum Management
- Continue magnesium sulfate 24 hours postpartum 3
- Monitor blood pressure q4h for 72 hours, then daily until normalized
- Antihypertensive therapy as needed (avoid methyldopa postpartum—use labetalol, nifedipine, or enalapril)
- Discharge education on warning signs (headache, visual changes, right upper quadrant pain)
- Follow-up within 7-10 days postpartum
Prevention in High-Risk Women
Low-dose aspirin (81-150mg daily) reduces preeclampsia risk by 15-20% when started before 16 weeks and continued until 36 weeks or delivery. 3, 8
Indications for aspirin prophylaxis:
- Previous preeclampsia, especially with adverse outcome
- Multifetal gestation
- Chronic hypertension
- Type 1 or 2 diabetes
- Renal disease
- Autoimmune disease
- ≥2 moderate risk factors (nulliparity, obesity, family history, age ≥35, low socioeconomic status, African American race)
Calcium supplementation (1.5-2g elemental calcium daily) reduces preeclampsia risk in women with low dietary calcium intake (<800mg/day). 3, 8
HELLP Syndrome
Definition and Diagnostic Criteria
HELLP syndrome is a severe manifestation of preeclampsia characterized by Hemolysis, Elevated Liver enzymes, and Low Platelets, occurring in 0.5-0.9% of all pregnancies and 10-20% of severe preeclampsia cases. 3, 8, 7
The American College of Obstetricians and Gynecologists requires all three components for diagnosis: 8
Hemolysis:
- Peripheral smear with schistocytes and fragmented RBCs 8
- LDH >295 U/L (reflects both hemolysis and hepatic dysfunction) 8
- Indirect bilirubin ≥18 µmol/L 8
- Elevated fibrin degradation products (>80 µg/L) 8
Elevated Liver enzymes:
Low Platelets:
- <100,000/mm³ (Tennessee Classification threshold) 8
Pathophysiology
Defective placental perfusion leads to endothelial dysfunction and thrombotic microangiopathy. 7
- Fibrin deposition in hepatic sinusoids causes sinusoidal obstruction and hepatic ischemia 7
- Can progress to subcapsular hematomas, parenchymal hemorrhage, and hepatic rupture 7
- 15% of HELLP cases occur without hypertension—do not exclude diagnosis based on normal blood pressure alone 7, 6
Clinical Presentation
Classic symptoms (present in 90%):
- Right upper quadrant or epigastric pain (most common—65-90%)
- Nausea/vomiting (45-85%)
- Malaise (90%)
- Headache (33-61%)
Physical examination:
- Right upper quadrant tenderness
- Hypertension (85% of cases)
- Edema
- Jaundice (rare, indicates severe disease)
Timing:
- 70% develop antepartum (27-37 weeks most common)
- 30% develop postpartum (usually within 48 hours but can occur up to 7 days)
Comprehensive Laboratory Workup
Initial assessment must include: 3, 8
- Complete blood count with peripheral smear examination for schistocytes 8
- Comprehensive metabolic panel: AST, ALT, LDH, total and indirect bilirubin 8
- Coagulation studies: PT, aPTT, fibrinogen, fibrin degradation products 8
- Renal function tests 8
- Type and crossmatch (anticipate transfusion needs)
Serial monitoring every 6-12 hours for 24-48 hours postpartum 8
Management Priorities
Immediate stabilization:
- Hospitalization in high-dependency or intensive care unit mandatory 3, 8
- Large-bore IV access (two sites)
- Continuous maternal and fetal monitoring
Blood pressure management:
- Non-severe hypertension (140-159/90-109 mmHg): Oral labetalol, nifedipine, or methyldopa 3, 8
- Severe hypertension (≥160/110 mmHg): Urgent IV treatment 3, 8
Seizure prophylaxis:
- Magnesium sulfate mandatory for all HELLP patients with co-existing severe hypertension 3, 8
- Standard dosing: 4-6g IV load, then 2g/hour maintenance 3
- Continue 24-48 hours postpartum 3
Management of coagulopathy:
- Platelet transfusion indicated when count <100,000/mm³ due to increased risk of abnormal coagulation and adverse outcomes 3, 8
- For cesarean section: Transfuse if platelets <50,000/mm³ 3, 8
- Fresh frozen plasma for INR >1.5 or active bleeding
- Cryoprecipitate for fibrinogen <200 mg/dL
Corticosteroid management:
- Do NOT give corticosteroids to improve maternal HELLP outcomes—no proven benefit 3, 8
- DO give betamethasone or dexamethasone for fetal lung maturity if delivery anticipated before 35 weeks 3, 8
Delivery decision-making:
- Prompt delivery indicated once maternal coagulopathy and severe hypertension corrected 3, 8
- Immediate delivery mandatory for: 8
- Severe thrombocytopenia with progressive decline
- DIC
- Hepatic hematoma or rupture
- Renal failure
- Placental abruption
- Non-reassuring fetal status
- Eclampsia
Mode of delivery:
- Vaginal delivery acceptable if cervix favorable and maternal/fetal status stable
- Cesarean section for obstetric indications or maternal instability
- Regional anesthesia contraindicated if platelets <70,000-80,000/mm³
Postpartum Monitoring and Recovery
Intensive monitoring required for 24-48 hours minimum: 3, 8
- Central venous pressure monitoring 3
- Hourly urine output 3
- Continuous blood pressure and ECG monitoring 3
- Oxygen saturation 3
- Serial labs every 6-12 hours 8
Expected recovery timeline:
- Platelet count nadirs 24-48 hours postpartum, then rises
- LDH peaks at 24-48 hours postpartum
- Liver enzymes normalize within days to weeks 3
- Platelet count normalizes within 6-11 days 3
Hepatic Complications
Subcapsular hematoma and hepatic rupture are rare but life-threatening:
- Perform abdominal ultrasound if severe right upper quadrant pain, shoulder pain, or hemodynamic instability 3, 8
- Be especially vigilant with severe thrombocytopenia 3, 8
- CT or MRI for definitive diagnosis
- Surgical consultation mandatory
- Management ranges from conservative (stable hematoma) to surgical intervention or hepatic artery embolization
Prevention in Subsequent Pregnancies
Women with prior HELLP syndrome have 19-27% recurrence risk and require high-risk obstetric care: 3, 8
- First-trimester screening (11-14 weeks) to assess early-onset preeclampsia risk 3, 8
- Aspirin prophylaxis 150mg nightly started before 16 weeks and continued until 36 weeks, delivery, or HELLP diagnosis 3, 8
- Calcium supplementation (1.5-2g elemental calcium daily) if dietary intake <800mg/day 3, 8
- Serial growth ultrasounds and antenatal testing
- Delivery planning at tertiary care center
Key Clinical Pitfalls to Avoid
- Do not dismiss symptoms in normotensive patients—15% of HELLP occurs without hypertension 7, 6
- Do not delay delivery for corticosteroid administration in unstable patients 3
- Do not use corticosteroids to treat maternal HELLP syndrome—only for fetal lung maturity 3, 8
- Do not perform neuraxial anesthesia with platelets <70,000-80,000/mm³ 3
- Do not discharge patients early—disease can worsen postpartum 8