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📚 SEM 6 OBSTETRICS - COMPREHENSIVE NOTES

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1. HYPERTENSION IN PREGNANCY

Definition & Classification

Risk Factors for Pre-eclampsia

• Primigravida (most common), multiple pregnancy, previous PE
• Diabetes, renal disease, autoimmune (SLE, antiphospholipid syndrome)
• Obesity (BMI >35), age >40, family history
• MNEMONIC: "PRIMD" - Primi, Renal, Immune, Multiple, Diabetes

Pathophysiology of Pre-eclampsia

1. Abnormal placentation - failure of trophoblast invasion of spiral arteries
2. Spiral arteries remain narrow → placental ischaemia
3. Imbalance: ↑ Thromboxane A2 / ↓ Prostacyclin → vasoconstriction
4. ↑ sFlt-1 (anti-angiogenic) / ↓ PlGF → endothelial dysfunction
5. Systemic endothelial damage → HTN, proteinuria, oedema

Severe Pre-eclampsia Features

• BP ≥ 160/110 mmHg
• Proteinuria ≥ 5g/24h
• Oliguria (<500 mL/24h)
• Headache, visual disturbances, epigastric pain
• Pulmonary oedema, IUGR, thrombocytopenia (<100,000)

Management

• First-line: Labetalol, Methyldopa, Nifedipine
• Avoid: ACE inhibitors, ARBs (teratogenic - renal agenesis)
• Target BP: 130-150/80-100 mmHg

• IV Labetalol (20 mg bolus) OR IV Hydralazine OR oral Nifedipine

• Definitive treatment = DELIVERY
• Severe PE: Deliver at ≥34 weeks; <34 weeks stabilise first
• MgSO4 (Magnesium Sulphate) for seizure prophylaxis
  • Loading dose: 4g IV over 20 min
  • Maintenance: 1-2 g/hr IV
  • Antidote: Calcium Gluconate 1g IV
  • Monitor: Reflexes (lost first), RR, UO
• Antihypertensives, fluid restriction, HDU/ICU

1. Left lateral position, secure airway
2. MgSO4 (as above) - drug of choice
3. Control BP
4. Deliver baby once stabilised
5. ICU monitoring

HELLP Syndrome

• H: Haemolysis (LDH >600, fragmented red cells)
• EL: Elevated Liver enzymes (AST/ALT >70)
• LP: Low Platelets (<100,000)
• Management: Steroids, correct coagulopathy, deliver
• Complications: DIC, subcapsular liver haematoma, renal failure

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2. GESTATIONAL DIABETES MELLITUS (GDM)

Definition

Pathophysiology

• Placental hormones (hPL, progesterone, oestrogen, cortisol) = diabetogenic
• Progressive insulin resistance in 2nd/3rd trimester
• Normally compensated by ↑ insulin secretion - fails in GDM

Risk Factors

• BMI >30, previous GDM, family history T2DM
• Previous macrosomic baby (>4.5 kg), polycystic ovary syndrome
• Ethnicity (South Asian, Middle Eastern, Black)
• Age >35, previous stillbirth

Screening & Diagnosis

Maternal Complications

• Pre-eclampsia, UTI, polyhydramnios
• Operative delivery, PPH
• Future T2DM (50% lifetime risk)

Fetal/Neonatal Complications

• Macrosomia → shoulder dystocia
• Polyhydramnios, stillbirth
• Neonatal hypoglycaemia (most common neonatal complication)
• Hypocalcaemia, polycythaemia, jaundice
• Respiratory distress syndrome

Management

• Low GI diet, 3 meals + 3 snacks/day
• Target: Fasting <5.3, 1hr post-meal <7.8, 2hr <6.4 mmol/L

• Start with Isophane (NPH) insulin at bedtime
• Rapid-acting insulin (Aspart/Lispro) with meals if needed

• Aim delivery at 38-39 weeks (or earlier if poor control)
• Sliding scale insulin during labour
• Glucose monitoring q1h, target 4-7 mmol/L

• Stop insulin after delivery
• OGTT at 6-8 weeks postpartum (to exclude T2DM)
• Lifestyle advice to prevent T2DM

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3. FETAL GROWTH RESTRICTION (FGR)

Definition

• Estimated fetal weight (EFW) or abdominal circumference (AC) <10th centile for gestational age
• "Small for gestational age" (SGA): birth weight <10th centile
• Severe FGR: EFW <3rd centile OR abnormal Doppler

Classification

Causes

Investigations

• Ultrasound: EFW, AC, growth velocity (serial scans q2 weeks)
• Doppler USS:
  • Umbilical artery (UA): First abnormal - raised PI/RI → absent end-diastolic flow (AEDF) → reversed end-diastolic flow (REDF)
  • Middle Cerebral Artery (MCA): Brain-sparing = low MCA resistance
  • Cerebroplacental Ratio (CPR): MCA PI/UA PI (<1 = brain sparing = poor prognosis)
  • Ductus Venosus (DV): Absent/reversed a-wave = immediate delivery
• CTG: Biophysical profile, non-stress test

Doppler Sequence in Deterioration

Management

• No specific treatment to reverse FGR
• Treat underlying cause (stop smoking, optimise maternal disease)
• Surveillance: Growth scans q2 weeks, Doppler, CTG, BPP
• Corticosteroids if preterm delivery anticipated
• Timing of delivery:
  • AEDF ≥ 34 weeks: deliver
  • REDF: deliver regardless of gestation (≥28 weeks)
  • DV abnormal: immediate delivery if viable
• Route: CS often preferred for severe FGR

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4. PRETERM LABOUR (PTL)

Definition

• Extremely preterm: <28 weeks
• Very preterm: 28-32 weeks
• Moderate/late preterm: 32-37 weeks

Causes/Risk Factors

• Previous PTL (strongest risk factor - 20-30% recurrence)
• Multiple pregnancy, polyhydramnios
• Uterine anomaly (bicornuate, fibroids)
• Cervical incompetence/short cervix (<25 mm at 24 weeks)
• Infection/PPROM, placenta praevia/abruption
• Smoking, low socioeconomic status

Pathophysiology

• Inflammatory cascade (infection/inflammation most common mechanism)
• Prostaglandin release → myometrial contractions
• Cervical ripening via metalloproteinases

Diagnosis

• Clinical: Contractions + cervical change (dilation ≥2 cm OR 80% effacement)
• Fetal Fibronectin (fFN): Cervicovaginal swab between 22-35 weeks
  • If negative: >95% will NOT deliver in 14 days (high NPV - reassuring)
  • If positive: 17% deliver within 14 days (moderate PPV)
• Cervical length (TVS): <25 mm at 22-24 weeks = high risk

Management

Prevention:

• Progesterone (Vaginal): For short cervix ≤25 mm or previous PTL
• Cervical cerclage: For cervical incompetence or short cervix

Acute Management (In-hospital):

• Nifedipine (1st line) - calcium channel blocker
• Atosiban (oxytocin receptor antagonist) - if nifedipine contraindicated
• NOT for use >34 weeks or if infection present
• Indometacin (<32 weeks only - risk of premature ductus closure)

• Betamethasone 12 mg IM x2 doses, 24 hours apart
• OR Dexamethasone 6 mg IM x4 doses, q12h
• Between 24-35+6 weeks
• Promotes: Lung maturity (surfactant), brain protection, gut maturity
• Benefits seen 24 hours after first dose, maximum at 48 hours

• Given <32 weeks for fetal neuroprotection (reduces cerebral palsy risk)
• 4g IV loading dose, 1g/hr maintenance until delivery/32 weeks

• NOT routinely for PTL (may worsen outcomes if membranes intact)
• GBS prophylaxis: Penicillin G if GBS positive or unknown
• If PPROM: Erythromycin 250 mg QDS for 10 days

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5. ABNORMAL PRESENTATION

Definitions

• Presentation: Presenting part of fetus at the pelvic inlet
• Position: Relation of denominator to maternal pelvis
• Lie: Relation of long axis of fetus to long axis of mother

Types of Abnormal Presentation

A. BREECH PRESENTATION

• Frank/Extended breech (65%): Hips flexed, knees extended (most common)
• Complete breech (10%): Hips & knees flexed (like sitting cross-legged)
• Footling breech (25%): One or both feet present

• Leopold's manoeuvres: Hard, ballotable head in fundus; soft irregular breech at pelvis
• Auscultation: FHR heard above umbilicus
• Confirm: Ultrasound

• ECV (External Cephalic Version): Offered at 36 weeks (nullipara) / 37 weeks (multipara)
  • Success rate ~50%
  • Contraindications: Placenta praevia, previous uterine scar (relative), PPROM, fetal compromise, multiple pregnancy
  • Give Tocolytic (Terbutaline) before, Anti-D if Rh negative
• If ECV fails or declined:
  • Planned CS (recommended - safer for baby)
  • Vaginal breech delivery: Only in experienced centres with informed consent
    • Criteria: Frank breech, adequate pelvis, normal fetus, no hyperextended neck, experienced obstetrician

B. FACE PRESENTATION

• Denominator: Mentum (chin)
• Mentoanterior: Can deliver vaginally
• Mentoposterior: CANNOT deliver vaginally → CS

C. BROW PRESENTATION

• Largest presenting diameter (mentovertical = 13.5 cm)
• Always requires CS (cannot deliver vaginally at term)

D. SHOULDER/TRANSVERSE LIE

• Always CS (unless second twin or very preterm)
• Neglected shoulder presentation → obstructed labour → uterine rupture risk

E. COMPOUND PRESENTATION

• Limb alongside presenting part
• Often resolves spontaneously; if persistent → CS

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6. POSTPARTUM HAEMORRHAGE (PPH)

Definition

• Primary PPH: Blood loss ≥500 mL within 24 hours of vaginal delivery OR ≥1000 mL after CS
• Severe PPH: ≥1000 mL within 24 hours
• Secondary PPH: Abnormal/excessive bleeding from 24 hours to 12 weeks postpartum

The 4 T's (Causes)

Risk Factors

• Previous PPH, placenta praevia/accreta/percreta
• Multiple pregnancy, macrosomia, polyhydramnios
• Prolonged labour, precipitate labour, instrumental delivery
• Pre-eclampsia, anticoagulation therapy

Management (SYSTEMATIC - "HAEMOSTASIS")

Step 1: Initial Resuscitation (Call for help immediately)

• 2 large-bore IV cannulae, FBC, clotting, G&S/cross-match
• Crystalloid/blood replacement
• Oxygen, catheterise (monitor UO)
• "Rub up" uterus (bimanual massage)

Step 2: Uterotonics (Tone - 1st line)

• Oxytocin (Syntocinon): 10 IU IM (already given prophylactically in 3rd stage) → 40 IU in 500 mL at 125 mL/hr IV
• Ergometrine 0.5 mg IM/IV (avoid in HTN)
• Syntometrine = oxytocin + ergometrine
• Carboprost (PGF2α, Hemabate): 0.25 mg IM q15 min (max 8 doses) - contraindicated in asthma
• Misoprostol 800-1000 mcg rectally/sublingually
• Tranexamic Acid (TXA): 1g IV ASAP (<3 hours of PPH) - CRASH-2/WOMAN trial

Step 3: Surgical/Procedural Options

• Bimanual uterine compression
• Intrauterine balloon tamponade (Bakri balloon, Sengstaken-Blakemore)
• Uterine compression sutures: B-Lynch suture (most common), Hayman suture
• Uterine artery ligation / Internal iliac artery ligation
• Interventional Radiology: Uterine artery embolisation (UAE)
• Hysterectomy: Last resort (peripartum hysterectomy)

Active Management of 3rd Stage (AMTSL) - Prevention:

• Oxytocin 10 IU IM within 1 minute of delivery (WHO recommended)
• Delayed cord clamping (≥1 min)
• Controlled cord traction

Secondary PPH

• Causes: Retained products (most common), endometritis, gestational trophoblastic disease
• Management: USS, antibiotics (metronidazole + amoxicillin), surgical evacuation if needed

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7. OBSTETRIC EMERGENCIES

A. ECLAMPSIA

• MgSO4 is drug of choice for seizure treatment and prophylaxis

B. SHOULDER DYSTOCIA

• H - Call for Help
• E - Evaluate for Episiotomy (only helps with soft tissue, not bony dystocia)
• L - Legs (McRoberts manoeuvre): hyperflex thighs onto abdomen → flattens lumbar lordosis
• P - Suprapubic Pressure (not fundal!)
• E - Enter (internal manoeuvres): Rubin II, Woods screw
• R - Remove the posterior arm
• R - Roll the patient (Gaskin all-fours position) Last resort: Zavanelli manoeuvre (cephalic replacement + CS), deliberate clavicle fracture, symphysiotomy

C. AMNIOTIC FLUID EMBOLISM (AFE)

D. CORD PROLAPSE

1. Call for help, do NOT replace cord
2. Elevate presenting part manually (examiner's hand in vagina pushes presenting part up)
3. Mother in knee-chest or exaggerated Sims position (or Trendelenburg)
4. Fill bladder with 500 mL saline (helps elevate presenting part)
5. Keep cord warm, moist (do NOT handle excessively)
6. Emergency CS as soon as possible (Category 1)
7. If fully dilated and vaginal delivery imminent → forceps/ventouse

E. PLACENTAL ABRUPTION

F. UTERINE RUPTURE

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8. PARTOGRAM

Definition

Purpose

• Monitor progress of labour
• Early detection of abnormal labour patterns
• Guide decision-making (when to intervene)
• Communication tool

Components of the Partogram

A. FETAL CONDITION (Top section)

• Fetal heart rate (FHR): Recorded every 30 min (normal 110-160 bpm)
• Membranes/Liquor: I = intact; C = clear; M = meconium; B = blood
• Moulding: 0 = bones separated; 1+ = just touching; 2+ = overlapping but reducible; 3+ = fixed overlap

B. LABOUR PROGRESS (Middle section - most important)

• Cervical dilation (x): Plotted on graph
• Descent of head (O): Fifths palpable abdominally (5/5 = fully above, 0/5 = fully engaged)
• Contractions: Frequency per 10 min, duration (<20s, 20-40s, >40s), strength

Alert and Action Lines:

• Alert line: Expected rate of cervical dilation of 1 cm/hour in active phase (Friedman's curve adapted)
• Action line: 4 hours to the right of alert line (WHO) or 2 hours (some protocols)
• If cervical dilation crosses alert line → reassess; crosses action line → intervention (ARM, augmentation, or CS)

Active Phase:

• Begins at cervical dilation of 4 cm (revised WHO guidelines - previously 3 cm)
• Expected: ≥1 cm/hour

C. MATERNAL CONDITION (Bottom section)

• Oxytocin: Amount, concentration, rate
• Drugs/IV fluids given
• BP: Every 4 hours (every 30 min in pre-eclampsia)
• Pulse: Every 30 min
• Temperature: Every 4 hours
• Urine: Volume, protein, acetone

Abnormal Labour Patterns

• Prolonged latent phase: >20 h (nullipara), >14 h (multipara)
• Protraction disorders: Slow active phase dilation (<1 cm/hr)
• Arrest disorders: No progress for ≥2 hours
• Secondary arrest: After normal progress, dilation stops

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9. MULTIPLE PREGNANCY

Definition

• Twins: Dizygotic (DZ, fraternal, 2/3 of twins) or Monozygotic (MZ, identical, 1/3)
• Higher multiples: Triplets, quadruplets, etc.

Zygosity vs Chorionicity

Complications

Maternal:

• Hyperemesis, anaemia, varicose veins
• Pre-eclampsia (3x risk), GDM (2x risk)
• Polyhydramnios, malpresentation
• PPH (major risk - overdistended uterus)
• Preterm labour (50% deliver before 37 weeks)

Fetal:

• IUGR/FGR, prematurity
• Twin-to-Twin Transfusion Syndrome (TTTS): MCDA only
  • Donor twin: Oliguria → oligohydramnios → stuck twin, IUGR, anaemia
  • Recipient twin: Polyuria → polyhydramnios, cardiac failure, polycythaemia
  • Staging: Quintero staging I-V
  • Treatment: Laser photocoagulation of placental anastomoses (gold standard)
• Twin Anaemia Polycythaemia Sequence (TAPS): Chronic form
• Selective FGR (sIUGR): Weight discordance >25%
• TRAP sequence: Reversed arterial perfusion (acardiac twin)
• Monoamniotic: Cord entanglement risk

Antenatal Care

• Early USS for chorionicity determination
• DCDA: USS q4 weeks from 20 weeks
• MCDA: USS q2 weeks from 16 weeks (for TTTS screening)
• MCMA: USS weekly from 28 weeks
• Iron + folic acid supplementation (double dose)
• Aspirin 150 mg from 12 weeks (pre-eclampsia prevention)
• Cervical length screening

Intrapartum Management

• Deliver DCDA: 37 weeks
• Deliver MCDA: 36-37 weeks
• Deliver MCMA: 32-34 weeks (high risk - in-patient from 28 weeks)
• Twin 1 vertex: Trial of vaginal delivery
• Twin 2: After delivery of twin 1 - internal podalic version OR CS if transverse
• CS for: Both non-vertex, MCMA, triplets and above, fetal compromise

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10. POSTNATAL COMPLICATIONS

A. POSTNATAL DEPRESSION (PND)

• Baby Blues (3rd-5th day): Transient, self-limiting, emotional lability - normal, reassurance only
• PND (2 weeks - 6 months): Persistent low mood, anxiety, bonding difficulty - treat
• Puerperal Psychosis (1-2 weeks postpartum): Rare (1:500), severe - rapid onset, hallucinations, delusions, disorganised behaviour - PSYCHIATRIC EMERGENCY

• Mild: CBT, social support, health visitor input
• Moderate-Severe: SSRIs (Sertraline or Paroxetine preferred - compatible with breastfeeding)
• Puerperal psychosis: Admit (mother-baby unit), antipsychotics + mood stabilisers

B. POSTPARTUM THYROIDITIS

• Autoimmune - occurs in 5-10% postpartum
• Phase 1 (1-4 months): Hyperthyroid phase (thyrotoxicosis)
• Phase 2 (4-8 months): Hypothyroid phase (most symptomatic)
• Phase 3 (8-12 months): Resolution (majority)
• 20-30% develop permanent hypothyroidism
• Treatment: Symptomatic - beta-blockers for hyper phase; levothyroxine for hypo phase

C. MASTITIS & BREAST ABSCESS

• Mastitis: Breast inflammation ± infection, usually 2-6 weeks postpartum
• Organism: Staphylococcus aureus (most common)
• Treatment: Continue breastfeeding, flucloxacillin 500 mg QID x 10-14 days
• Abscess: Fluctuant, tender mass - requires aspiration (USS-guided) OR incision and drainage; stop breastfeeding from affected breast temporarily

D. THROMBOEMBOLIC DISEASE (VTE)

• Major cause of maternal death
• Risk highest in first 6 weeks postpartum
• DVT: Leg pain/swelling, usually left leg
• PE: SOB, pleuritic chest pain, haemoptysis
• Prevention: LMWH (e.g. Enoxaparin), TED stockings, early mobilisation
• Treatment: LMWH (preferred over warfarin in breastfeeding)
• Postpartum thromboprophylaxis: 10 days minimum after VD; 6 weeks after CS (high risk)

E. PUERPERAL SEPSIS

• Fever >38°C within first 10 days after delivery
• Most common organism: Group A Streptococcus (Strep. pyogenes) - most severe
• Other: E. coli, Staph. aureus
• Source: Uterus (endometritis), urinary tract, breast, wound
• Sepsis Six in 1 hour:
  1. Give O2
  2. Blood cultures
  3. IV antibiotics (broad spectrum: Piperacillin/tazobactam)
  4. IV fluids
  5. Check lactate
  6. Urine output monitoring
• Endometritis: Co-amoxiclav OR metronidazole + amoxicillin + gentamicin

F. SUBINVOLUTION OF UTERUS

• Failure of uterus to return to pre-pregnancy size
• Causes: Retained products, infection, fibroids
• Presents as: Persistent uterine enlargement, prolonged lochia, secondary PPH
• Treatment: Ergometrine (promotes uterine contraction), antibiotics, evacuation if retained products

G. POSTNATAL CHECK (6-8 WEEKS)

• Physical: BP, weight, wound check, uterine involution
• Perineal healing, urinary/faecal continence
• Mental health: EPDS screening
• Contraception counselling
• Breastfeeding assessment
• Immunisations (MMR if rubella non-immune)

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QUICK VIVA REVISION CARDS

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Study tip: For essay questions, always follow: Definition → Classification → Pathophysiology → Risk Factors → Diagnosis → Complications → Management. For viva, know your numbers (cut-offs, doses, timings) and the "why" behind every decision.