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L16: Postpartum Hemorrhage L17: Prenatal Diagnosis L18: Malposition L19: Prolonged Pregnancy L20: Induction of Labour L21: Hypertensive Disorders L22: Chronic Hypertension ⚖️ Ultimate Comparisons

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L16: Postpartum Hemorrhage (PPH)

Definition & Classification
  • Clinical Definition: Any amount of bleeding from or into the genital tract following birth up to the end of the puerperium, which adversely affects general condition evidenced by rise in pulse rate (Tachycardia) and falling blood pressure (Hypotension).
  • Quantitative Definition (World Health Organization - WHO): Blood loss > 500 mL following birth.
  • Average blood loss: Vaginal delivery = 500 mL, Cesarean delivery = 1000 mL, Cesarean hysterectomy = 1500 mL.
  • Major Obstetric Hemorrhage: Blood loss > 2,500 mL, or requiring blood transfusion of > 5 units of red cells, or treatment for coagulopathy.
  • Secondary PPH (Late): Occurs in 1-2%. Occurs most frequently between 7 and 14 days after birth. Majority due to sloughing of the placental site or endometritis (constant low abdominal pain, tender uterus, closed internal os).
Consequences & Complications
  • Acute hypovolemia and sudden/rapid cardiovascular decompensation.
  • Disseminated Intravascular Coagulation (DIC).
  • Pulmonary edema & Adult Respiratory Distress Syndrome (ARDS) (iatrogenic complications from fluid replacement and multiple transfusions).
  • Sheehan’s syndrome (Postpartum Pituitary Necrosis / Hypopituitarism) presenting earliest as failure of lactation (Reduced Prolactin). Also causes secondary amenorrhea, breast atrophy, and premature aging.
Causes (The 4 T's)
  • Tone (Uterine atony - most common cause).
  • Trauma (Lacerations, hematomas of genital tract/perineum/cervix).
  • Tissue (Retained products of conception / missing cotyledon / Placenta).
  • Thrombin (Coagulopathy / DIC). Occurs in: Abruptio placentae, Jaundice in pregnancy, Thrombocytopenic purpura, Severe preeclampsia, HELLP syndrome, or Intrauterine Death (IUD).
Risk Factors
  • Antenatal: Previous PPH, Previously retained placenta, Maternal Hemoglobin <= 8.5 g/dL at onset of labor, Increased BMI, Parity >= 4 (Grand multipara), Antepartum Hemorrhage (APH), Overdistention (multiple pregnancy, polyhydramnios), Uterine abnormalities/fibroids, Low-lying placenta, Age > 35 years.
  • Intrapartum: Induction of Labour (IOL), Prolonged labor (1st, 2nd, or 3rd stages), Use of oxytocin, Precipitate labor, Operative vaginal delivery (Forceps/Vacuum), Cesarean delivery.
Prevention & Prophylaxis
  • Keep Hemoglobin > 10 g/dL antenatally.
  • Blood grouping for all women.
  • Ultrasound to determine morbid adherent placenta in all women with prior cesarean delivery. Multidisciplinary team + Senior obstetrician required.
  • Active Management of 3rd Stage: Reduces PPH incidence from 15% to 5%. Involves:
    1. Intramuscular injection of 10 International Units (IU) Oxytocin (as anterior shoulder delivers or immediately after).
    2. Early clamping/cutting of umbilical cord.
    3. Controlled cord traction (Brandt-Andrews maneuver).
Clinical Management & Resuscitation (A, B, C)
  • Simultaneous approach: Communication, Resuscitation, Monitoring, Arrest of bleeding. (Essential if loss > 1000 mL or clinical shock).
  • Resuscitation: Insert TWO large-bore (14-gauge) Intravenous cannulas. Keep patient flat and warm. Insert urinary catheter to monitor output.
  • Give 100% Oxygen by mask 10–15 L/min.
  • Give warmed crystalloids (0.9% saline) and Haemaccel (colloids) - Haemaccel does NOT interfere with cross matching.
  • Send blood for FBC, group, crossmatch (ask for at least 6 units), RFT, LFT, coagulation screen including fibrinogen.
  • Give O negative blood if immediately needed (un-crossmatched).
  • Crucial Pearl: Hypotension is a VERY LATE sign occurring after 2,000 mL loss. Young fit women compensate extremely well up to 1000ml. Treat the patient, not the single Hb result.
Specific Management (Based on Cause)
  • Atonic Uterus (Flabby):
    • Step 1: Rub up/Massage the uterus & bimanual compression to express clots.
    • Step 2 (Drugs):
      - Syntometrine (Oxytocin 5 IU + Ergometrine 0.5 mg Intramuscular). Contraindicated in: Twin pregnancy (until 2nd baby out), Organic heart disease, Preeclampsia/Hypertension.
      - Oxytocin (Syntocinon) IV infusion (40 IU in 500 mL 0.9% saline over 4-6 hrs).
      - Misoprostol (Prostaglandin E1): 600 micrograms (μg) rectally (3 pessaries). Note: Not mg!
      - Carboprost / Prostodin (Prostaglandin F2α): 250 micrograms (μg) Intramuscular every 15 min (Max 2 mg). Note: Not mg!
    • Step 3 (Tamponade): Hydrostatic Balloon tamponade (Bakri, Foley, Condom) inflated with 200-500 mL water/saline. Mostly replaces uterine packing.
    • Step 4 (Surgery): Laparotomy. Options:
      1. Uterine artery ligation (lateral border between upper/lower segment).
      2. Compression of uterus (B-Lynch brace sutures).
      3. Angiographic selective arterial embolization (Interventional radiology, >90% success, avoids hysterectomy, uses gel foam).
      4. Hysterectomy (Subtotal or Total) as life-saving last resort. Early decision in parous women.
  • Traumatic PPH (Firm, contracted uterus + bleeding): Speculum exam & suture repair under general anesthesia if necessary.
  • Tissue (Retained pieces): Expelled placenta must be examined for missing cotyledons. Manual removal of placenta under General/Regional Anesthesia + antibiotics.

💡 Top 5 Hints & Pearls (Lec 16)

  • 1. Hypotension is deceiving: Young pregnant women compensate well. Blood pressure drops very late (>2000 ml loss). Rely on Tachycardia as an earlier sign.
  • 2. Drug Safety: Never give Syntometrine/Ergometrine to a woman with Pre-eclampsia or Heart Disease. Use Oxytocin or Misoprostol instead.
  • 3. Dosing Trap: Misoprostol and Carboprost doses are in Micrograms (μg), NOT milligrams (mg). This is a classic MCQ trap.
  • 4. The 4 T's Hierarchy: Always assess the Tone (flabby uterus) first as it is the most common cause. If uterus is firm and she is bleeding, think Trauma.
  • 5. Sheehan's Syndrome: The absolute earliest presentation of postpartum pituitary necrosis is the failure of lactation (agalactorrhea).

L17: Prenatal Diagnosis

Basics & Definitions
  • Prenatal Diagnosis: Identification of fetal disease prior to birth. Allows delivery planning, parental preparation, in utero treatment, or Termination of Pregnancy (TOP).
  • Counseling: Must be supportive, informative, and non-directional. Not all parents will wish to terminate. Written info should be provided.
Maternal Serum & Ultrasound Screening
  • Combined Test (Best 1st Trimester):
    - Timing: 11 to 13+6 weeks of gestation.
    - Procedure: Ultrasound for Nuchal Translucency (NT) + Maternal Blood test for PAPP-A (Pregnancy-Associated Plasma Protein A) and β-hCG.
    - Pros: High detection rate (~90% for 5% False Positive Rate). Can detect structural defects (e.g. cardiac). Early results allow surgical TOP.
    - Enhancers: Nasal bone length, Tricuspid regurgitation, Ductus venosus wave form.
  • Triple and Quadruple Tests (2nd Trimester):
    - Timing: 15 to 20 weeks. Used if NT scan missed or gestation advanced.
    - Triple: Oestriol, hCG, AFP (Alpha-fetoprotein).
    - Quadruple: Adds Inhibin A. Recommended by UK National Screening Committee for late bookings.
Non-Invasive Prenatal Testing (NIPT & NIPD)
  • Analyzes Cell-free fetal Deoxyribonucleic Acid (cffDNA) extracted from maternal blood. Originates from placenta (trophoblast). Detectable from 5 weeks, increases to ~10% at 10 weeks, then rapidly declines post-delivery.
  • NIPT Applications: Screens for aneuploidies (Down/T21, Patau/T13, Edwards/T18). Sensitivity approaches 100% with FPR <0.5%.
  • Limitations of NIPT: Do NOT perform before 10 weeks, or if NT > 3.5 mm, or if structural abnormality is visible on scan. Positive NIPT MUST be confirmed via CVS or Amniocentesis (false positives exist). Maternal obesity can hinder results.
  • NIPD (Diagnosis): Used for single-gene disorders (autosomal dominant like achondroplasia), fetal sex (for X-linked disorders), and Fetal Blood Group (RhD/Kell alloimmunization).
  • Whole Exome Sequencing: Focuses on protein-coding exons (1.5% of genome, ~22,000 genes). Cost-effective alternative to whole genome sequencing. Ideal for severe/multisystem anomalies (cardiac/skeletal) when karyotype is normal.
Ultrasound Soft Markers (20 weeks)
  • Features slightly more common in abnormal fetuses. The term 'soft markers' is not recommended in the UK.
  • Mild Renal Pelvic Dilatation: > 7mm at 20 weeks. ~1.5x risk increase. Repeat scan in 3rd trimester.
  • Echogenic Bowel: Brightness similar to bone. ~5-fold increase in chromosomal risk. Also linked to Cystic Fibrosis (CF), bowel obstruction, perinatal risk.
  • Increased Nuchal Fold: > 6mm in transverse section. ~10-fold increase in risk. Early sign of hydrops. Amniocentesis offered.
  • Mild Ventriculomegaly: > 10mm posterior horn. Needs neurosonography.
  • Normal Variants (NO LONGER significant): Choroid plexus cysts, Fetal intracardiac foci, Two-vessel cord, Dilated cisterna magna.
  • Fetal MRI: Superior soft tissue resolution. Confirms eligibility for fetal surgery (e.g. spina bifida by detecting Chiari II hindbrain herniation). Sensitive to fetal motion.
Invasive Diagnostic Tests
  • Chorionic Villus Sampling (CVS):
    - Extracts rapidly dividing trophoblast cells (mesenchyme of villi). Transabdominal or transvaginal.
    - Timing: After 11 weeks. (Reduces risk of limb reduction defects seen earlier).
    - Miscarriage risk: < 0.5% (1% in twins).
    - Major Issue: Confined Placental Mosaicism (<2% of cases, abnormal cell line in placenta but normal fetus; requires Amniocentesis for confirmation. Consult Clinical Genetics).
  • Amniocentesis:
    - Extracts 15–20 mL amniotic fluid (contains fetal cells).
    - Timing: After 15 weeks.
    - Miscarriage risk: < 0.5%.
    - Can detect fetal viral infections.
  • Cordocentesis:
    - Obtains fetal blood directly.
    - Main indication: Suspected severe fetal anemia or thrombocytopenia (allows immediate transfusion if needed).
  • Chromosomal Microarray Analysis (CMA): Newer technique from invasive samples. Identifies submicroscopic abnormalities undetectable by karyotyping. Needs careful counseling due to complex/uncertain results.
  • Note on Viral Screening: Do NOT carry out invasive procedures without reviewing maternal HIV and Hepatitis status due to risk of vertical transmission.

💡 Top 5 Hints & Pearls (Lec 17)

  • 1. NIPT Limitation: Cell-free DNA (NIPT) is excellent but it is a Screening test, NOT Diagnostic. A positive result MUST be confirmed with CVS or Amniocentesis.
  • 2. CVS vs. Amniocentesis Timing: CVS is done after 11 weeks, while Amniocentesis is done after 15 weeks.
  • 3. Confined Placental Mosaicism: This is a unique complication of CVS (because it samples the placenta, not the fetus itself), occurring in <2%.
  • 4. Obesity effect: Maternal obesity can cause NIPT failure because the fraction of fetal cffDNA gets diluted in a larger maternal blood volume.
  • 5. Soft Markers Updates: Choroid plexus cysts and two-vessel cords are no longer considered significant markers for chromosomal abnormalities.

L18: Malposition

Definition & Risk Factors
  • Definition: Any position of the vertex other than flexed occipitoanterior. Most common is Occipitoposterior (OP) (occiput points laterally or to posterior half of pelvis).
  • Key Feature: Associated with a deflexed head presenting a larger anteroposterior diameter.
  • Incidence: ~10% of all vertex presentations at labor onset.
  • Causes/Risk Factors: In majority, cause is not clear. Predisposing factors: Epidural analgesia, nulliparity, greater fetal weight, prior delivery with OP positioning, and an Anthropoid pelvis with a narrow subpubic angle.
Diagnosis
  • Abdominal Inspection: Abdomen looks flat below the umbilicus.
  • Abdominal Palpation:
    - Fetal limbs easily felt near midline.
    - Fetal back felt far away in the flank (difficult to outline).
    - Head is not engaged.
    - Cephalic prominence (sinciput) is not as prominent as in well-flexed OA. In direct OP, small sinciput confused with breech.
  • Auscultation: Fetal Heart Sounds (FHS) max intensity is on the flank (hard to locate in Left Occipitoposterior - LOP). In direct OP, FHS distinctly felt in midline.
  • Vaginal Examination (Early Labor):
    - Elongated bag of membranes (likely to rupture during exam).
    - Sagittal suture occupies oblique diameters. Posterior fontanel near sacroiliac joint.
    - Anterior fontanel easily felt due to deflexion (sometimes felt at a lower level than posterior).
  • Vaginal Examination (Late Labor): Difficult due to caput formation obliterating sutures. Locate the unfolded pinna of the ear (points toward occiput). Ultrasound is helpful.
Mechanism of Labor in OP
  • Engagement: Delayed due to deflexion. Engages through right oblique (ROP) or left oblique (LOP). Engaging transverse diameter: Biparietal (9.5 cm). Engaging AP diameter: Suboccipitofrontal (10 cm) or Occipitofrontal (11.5 cm).
  • Favorable Circumstances (90%): Good uterine contractions -> Flexion -> long anterior internal rotation of occiput (3/8th of a circle) -> Spontaneous delivery by extension.
  • Unfavorable Circumstances (10% - Malrotation/Nonrotation): Deflexion persists, weak contractions, flat sacrum, prominent ischial spines, convergent side walls, big baby. Leads to:
    1. Incomplete forward rotation: leads to Deep Transverse Arrest (DTA).
    2. Non-rotation: Oblique posterior arrest.
    3. Malrotation (posterior rotation 1/8th circle): Leads to Persistent Occipitoposterior Position (POP) / Occipitosacral.
  • Outcomes of POP: Arrest, OR if pelvis is adequate (Spacious Gynecoid or Anthropoid), spontaneous delivery as "face to pubis".
Deep Transverse Arrest (DTA)
  • Definition: Head deep into cavity, sagittal suture placed in the transverse bispinous diameter, no progress in descent >30 min despite good uterine contractions.
  • Causes: Faulty pelvic architecture (prominent ischial spines, flat sacrum, convergent side walls), deflexion of head, weak uterine contractions, laxity of pelvic floor muscles.
  • Diagnosis: Head is engaged, sagittal suture in transverse bispinous diameter, anterior fontanel palpable.
  • Management: Depends on fetal condition and pelvis.
    - If vaginal delivery unsafe (inadequate pelvis/big baby): Cesarean Section.
    - If vaginal delivery safe (adequate pelvis): Ventouse (ideal), Manual rotation and forceps application, or Forceps rotation & delivery (Kielland Forceps - only by expert). Deep episiotomy often needed.
Complications
  • Maternal: Prolonged second-stage labor, increased rates of Cesarean delivery and operative vaginal delivery. Higher rates of blood loss and Obstetric Anal Sphincter Injuries (OASIS).
  • Neonatal: Higher rates of acidemic umbilical cord gases, birth trauma, Apgar scores < 7, and NICU admission compared to OA position.

💡 Top 5 Hints & Pearls (Lec 18)

  • 1. The "Flat" Abdomen: In OP malposition, the abdomen looks characteristically flat below the umbilicus because the fetal limbs are anterior.
  • 2. Fontanel Feeling: Normally, the posterior fontanel is felt. In OP with a deflexed head, the Anterior fontanel is easily felt, sometimes even lower than the posterior.
  • 3. Deep Transverse Arrest Landmark: Arrest specifically occurs at the transverse bispinous diameter (ischial spines).
  • 4. Favorable Outcome: 90% of OP positions will spontaneously flex and rotate anteriorly given good uterine contractions. Expectant management is the initial policy.
  • 5. "Face to Pubis" Delivery: This is a spontaneous vaginal delivery outcome of a Persistent Occipitoposterior (POP) position, occurring if the pelvis is Anthropoid or spacious gynecoid.

L19: Prolonged Pregnancy

Definitions & Incidence
  • Full term: 39+0 to 40+6 weeks of gestation.
  • Late term: 41 to 41+6 weeks of gestation.
  • Post-term / Prolonged Pregnancy: Pregnancy that continues beyond 42 weeks of gestation.
  • Post-dates: Passed the Estimated Due Date (EDD) of 40 weeks.
  • Incidence: Complicates 5–10% of pregnancies. Routine early ultrasound dating significantly reduces the rate of false-positive diagnoses.
Causes & Risk Factors
  • Maternal Factors: Inaccurate dating (most common cause), primigravidas, previous prolonged pregnancy, genetic predisposition (white race), obesity. Diets rich in n-3-polyunsaturated fatty acids (PUFA) increase incidence by interfering with uterine production of prostaglandins.
  • Placental Factors: Placental sulphatase deficiency (a rare X-linked recessive disorder).
  • Fetal Factors: Fetal adrenal insufficiency/hypoplasia, Anencephaly, Male fetuses.
Fetal & Maternal Risks
  • Fetal & Neonatal Risks: Fetal distress (placental dysfunction), oligohydramnios, Postmaturity syndrome (IUGR, meconium-stained liquor, loss of subcutaneous fat, cracked peeling skin - signs of placental insufficiency), increase in stillbirth rates, meconium aspiration, neonatal acidemia, low Apgar scores. Fetal macrosomia -> shoulder dystocia -> orthopedic/neurological injury, cerebral palsy. Neonatal hypothermia, hypoglycemia, hypocalcemia.
  • Maternal Risks: Increase in labor dystocia, severe perineal injury (related to macrosomia), operative vaginal delivery, and a doubling in the rate of caesarean delivery. Risks are heavily amplified in obese women. High emotional impact (anxiety/frustration).
Management
  • Step 1: Accurate dating of pregnancy (Routine ultrasound).
  • Step 2: Assessment of fetal/maternal wellbeing.
  • Step 3: Uncomplicated pregnancies should be offered Induction of Labour (IOL) beyond 41 weeks.
  • Step 4: If women decline IOL at 42 weeks, offer increased antenatal monitoring: twice-weekly CTG and ultrasound for maximum amniotic pool depth.
  • Membrane Sweeping: Reduces need for formal IOL. No evidence it increases maternal/neonatal infection or PROM. Balance with patient discomfort.
  • Indications for IMMEDIATE IOL/Delivery post-dates: Reduced amniotic fluid on scan, reduced fetal growth, reduced fetal movements, imperfect CTG, maternal hypertension or significant medical condition.
  • Counseling on expectant management (>42w): Important to state that no test can guarantee the safety of her baby and perinatal mortality/morbidity increases.

💡 Top 5 Hints & Pearls (Lec 19)

  • 1. True Definition: Prolonged/Post-term specifically means >42 completed weeks, not just passing the EDD.
  • 2. Most Common Cause: The number one reason a pregnancy appears prolonged is simply inaccurate dating (hence the importance of early USS).
  • 3. Postmaturity Syndrome: Look for the triad of loss of subcutaneous fat, cracked skin, and meconium-staining due to placental insufficiency.
  • 4. Fetal Pituitary-Adrenal Axis: Conditions affecting this axis, like Anencephaly and Fetal Adrenal Hypoplasia, are classic fetal causes of prolonged pregnancy.
  • 5. Dietary Factor: High intake of Omega-3 (n-3 PUFA) can delay labor by inhibiting prostaglandin synthesis.

L20: Induction of Labour (IOL)

Definition & Concepts
  • Induction of Labour (IOL): The planned artificial initiation of labor prior to its spontaneous onset.
  • Augmentation: The artificial stimulation of labor that has already begun spontaneously.
  • Accounts for 20-30% of UK births.
  • Principle: Performed when the risks of continuing the pregnancy outweigh the risks of delivery.
Indications & Contraindications
  • Indications: Prolonged pregnancy (offered >41 weeks), Premature Rupture of Membranes (PROM) >24 hours, Pre-eclampsia, Fetal Growth Restriction (FGR), Diabetes Mellitus, Macrosomia, Deteriorating maternal illness, Twin pregnancy >38 weeks, Unexplained APH.
  • Absolute Contraindications: Complete placenta praevia, Vasa praevia, Transverse fetal lie, Umbilical cord prolapse, Previous classical cesarean section, Previous myomectomy entering the endometrial cavity, Severe fetal compromise.
  • Relative Contraindications: Breech presentation, Previous lower segment cesarean section, Preterm <34 weeks, Deteriorating maternal condition (severe APH, severe cardiac disease).
  • Social IOL: Controversial. Done to satisfy domestic/organizational needs. Mostly discouraged. Acceptability depends heavily on multiparity and a favorable cervix.
Predictors of Success (Bishop Score)
  • Strong predictors for successful IOL: Gestational age, Parity, and Bishop's score (measure of cervical 'ripeness').
  • Bishop Score components: Cervix becomes softer, shortens, moves forwards, effaces, and dilates.
  • High score (favorable) = easier, shorter induction, less likely to fail.
  • Low score (unfavorable) = longer IOL, higher chance of failure leading to Cesarean section.
  • Favorable clinical factors: Younger age, multiparity, BMI < 30 kg/m2, favorable cervix, birth weight < 3500g.
Methods & Monitoring
  • Assessment before IOL: Abdominal assessment of head engagement, ultrasound if position uncertain, record Bishop score, confirm normal FHR pattern (CTG), confirm absence of significant uterine contractions.
  • Pharmacological: Dinoprostone (PGE2) or Misoprostol (PGE1). Major risk is Uterine Hyperstimulation.
    - If hyperstimulation occurs: Stop medication, remove vaginal product. Dinoprostone controlled-release system is easily removed; gels/tablets are not.
    - Treat with tocolysis. Hyperstimulation from Misoprostol is harder to reverse.
  • Mechanical: Balloon catheters. Less likely to cause hyperstimulation compared to drugs.
  • Non-pharmacological (Not supported by evidence): Herbal supplements, acupuncture, homeopathy, castor oil, hot baths, enemas, sexual intercourse.
  • Monitoring: Continuous Intrapartum Cardiotocography (CTG) required regularly. Re-assess Bishop score 6 hours after PGE2 tablet/gel, or 24 hours after controlled-release pessary.

💡 Top 5 Hints & Pearls (Lec 20)

  • 1. Definition trap: Induction is starting labor from scratch. Augmentation is speeding up a slow labor that already started naturally.
  • 2. Absolute Contraindication: Never induce a patient with Vasa praevia or Complete placenta praevia (will cause catastrophic hemorrhage).
  • 3. Myomectomy rules: A previous myomectomy is only an absolute contraindication to IOL if the surgery entered the endometrial cavity (risk of rupture).
  • 4. Hyperstimulation Reversal: Dinoprostone strings are easy to pull out to stop hyperstimulation. Misoprostol pills melt and are much harder to reverse.
  • 5. The Bishop Score: The single best cervical predictor of induction success. High score = ready for labor. Low score = high risk of C-section.

L21: Hypertensive Disorders of Pregnancy

Definitions & Classification
  • Affects ~10% of pregnancies. Pre-eclampsia affects ~2-3% and is a leading cause of maternal mortality in the UK.
  • Three main classifications:
    1. Non-proteinuric pregnancy-induced hypertension (Gestational hypertension).
    2. Pre-eclampsia.
    3. Chronic hypertension.
  • Pre-eclampsia Diagnosis: New-onset gestational hypertension (Systolic >= 140 mmHg and/or Diastolic >= 90 mmHg) associated with new onset of at least ONE of:
    - Proteinuria.
    - Maternal organ dysfunction (liver, neuro, hematological, renal).
    - Uteroplacental dysfunction.
    All occurring at or after 20 weeks' gestation. May present for the first time intra-partum or in the puerperium.
  • BP Measurement: Measured on at least two occasions 4 hours apart.
Proteinuria & Labs
  • Dipstick: >=1+ warrants quantifying. >=2+ is probable significant proteinuria. Automated reading device preferred.
  • Protein:creatinine ratio (Spot test): > 30 mg/mol (Fast, within 1 hr). Highly recommended.
  • 24-hour collection: 300 mg/24 hours (Gold standard but slow/inconvenient).
  • Additional Labs: FBC (falling platelets/rising hematocrit), Creatinine, LFTs, Uric acid.
  • Angiogenic Markers: Placental Growth Factor (PlGF) and sFlt-1:PlGF ratio. sFlt-1 antagonizes PlGF/VEGF causing vasoconstriction and endothelial dysfunction.
Pathophysiology & Systems Involved
  • Root Cause: Abnormal trophoblast invasion in 1st trimester -> failure of low-resistance uteroplacental circulation.
  • Cardiovascular: Marked peripheral vasoconstriction, loss of endothelial integrity (vascular permeability), generalized edema (face/hands).
  • Renal: Glomeruloendotheliosis (highly specific to pre-eclampsia). Impairs filtration, causes proteinuria, lowers oncotic pressure (edema).
  • Liver / Hematology: Endothelial damage -> platelet consumption -> fibrin deposition.
  • HELLP Syndrome: Hemolysis, Elevated Liver enzymes, Low Platelets. Severe form (2-4% of cases). Present with epigastric pain, N/V. BP may be mild/absent. High fetal loss (up to 60%).
  • Neurological: Vasospasm + cerebral edema. Pre-eclampsia + Convulsions = Eclampsia. Hyperreflexia and clonus (>3 beats) are warning signs.
  • Fetus: Fetal Growth Restriction (FGR). Uterine artery Doppler shows high resistance with a characteristic 'notch'.
Management: Mild to Severe Hypertension
  • Cure: The only cure is to deliver the baby and placenta.
  • Mild to Moderate (140/90 to 159/109): Target BP <= 135/85. Monitor BP every 48h. Labs twice weekly. FHS every visit. US every 2 weeks.
  • Severe (>= 160/110 mmHg): Admit immediately. Measure BP every 15-30 min. Labs 3 times/week.
  • Pharmacology (NICE Guidelines):
    1. Labetalol: Alpha/Beta blocker. First line. IV bolus 20mg, escalating to 220mg max. Continuous infusion if needed.
    2. Nifedipine: Calcium-channel blocker. Rapid onset. Can cause severe headache mimicking worsening disease.
    3. Methyldopa: Centrally acting. Longest safety record but takes 24 hours to act.
    4. Hydralazine (IV) if labetalol ineffective.
  • Maternal Mortality Causes: 1. Cerebral Hemorrhage. 2. ARDS. Keep MAP < 125 mmHg to prevent stroke. Avoid repetitive fluid challenges.
  • Delivery Indications: Inability to control BP, deteriorating liver/renal function, falling platelets, neurological complications, non-reactive CTG. Delivery at 37 weeks improves outcomes without affecting mode of delivery.
Eclampsia, Fluid Mgmt & Anesthesia
  • Anticonvulsant: Magnesium Sulphate (MgSO4) is the drug of choice. Superior to diazepam/phenytoin (less maternal ventilation/pneumonia). Acts as membrane stabilizer/vasodilator. Halves risk of eclampsia. Reduces Cerebral Palsy risk in preterm (<32w).
  • MgSO4 Dose: 4g (up to 8g) IV loading, then 1-2 g/h maintenance.
  • Toxicity: Renally excreted (watch oliguria). First sign is loss of patellar reflexes, then respiratory arrest, then cardiac arrest.
  • Antidote: 10 mL of 10% Calcium Gluconate.
  • Fluid Mgmt: High risk of pulmonary edema (ARDS). Strict fluid restriction (e.g., 80 mL/h total). Consider dopamine if CVP >8 with oliguria.
  • Anesthesia: Regional blockade preferred. Endotracheal intubation (GA) can cause dangerous severe hypertension. Check platelets (safe if > 80 x10^9/L) to avoid epidural hematoma.
  • Postnatal: Review at 6-12 weeks postpartum.

💡 Top 5 Hints & Pearls (Lec 21)

  • 1. Pre-eclampsia Timeline: By definition, it occurs after 20 weeks gestation. If HTN is seen before 20 weeks, it is Chronic Hypertension.
  • 2. The "Cure": Antihypertensives only manage the symptoms. The only definitive cure for pre-eclampsia is delivery of the placenta.
  • 3. Magnesium Toxicity Progression: The order of failure is critical: 1st Loss of reflexes -> 2nd Respiratory arrest -> 3rd Cardiac arrest. Keep Calcium Gluconate ready!
  • 4. HELLP Trap: A patient with HELLP syndrome can present with severe epigastric pain (liver swelling/capsule stretching) while her blood pressure might be completely NORMAL or mild.
  • 5. Anesthesia Choice: Avoid General Anesthesia if possible. Laryngoscopy triggers a massive sympathetic response leading to fatal hypertensive spikes and intracerebral hemorrhage. Use Regional.

L22: Chronic Hypertension

Definition & Causes
  • Definition: Hypertension present before pregnancy or before 20 weeks gestation. May present for first time in pregnancy but initially masked by 1st-trimester physiological vasodilation.
  • Causes:
    - Essential hypertension (90% of cases). Diagnosis of exclusion.
    - Secondary hypertension: Needs exclusion.
    • Renal disease (accounts for >80% of secondary cases: polycystic disease, diabetic nephropathy, chronic glomerulonephritis).
    • Vascular (Renal artery stenosis, Coarctation of aorta).
    • Endocrine (Phaeochromocytoma, Conn's, Cushing's).
    • Collagen/Connective tissue (Systemic Sclerosis, SLE, Rheumatoid).
Risks & Management
  • Maternal & Fetal Risks: Superimposed pre-eclampsia, placental abruption, heart failure, intracerebral hemorrhage. Fetal morbidity.
  • Superimposed Pre-eclampsia: Develops in ~33% of cases (one-third). More likely if severe HTN or renal disease.
  • Risk factors for Superimposed Pre-eclampsia: Renal disease, Maternal age >40, Pre-existing Diabetes, Multiple pregnancy, Connective tissue disease (Antiphospholipid), early BP >160/100, Pre-pregnancy BMI > 35, previous pre-eclampsia.
  • Management: Mild cases (<150/100 mmHg) do not require immediate treatment. Regarded as high-risk. Monitor closely for proteinuria (indicates superimposed pre-eclampsia) and Fetal Growth Restriction (FGR) via serial ultrasounds. Evaluate with serum creatinine, electrolytes, autoantibodies, ECG/ECHO if secondary suspected.

💡 Top 5 Hints & Pearls (Lec 22)

  • 1. The 20-Week Rule: Hypertension before 20 weeks = Chronic. Hypertension after 20 weeks = Gestational/Pre-eclampsia.
  • 2. The 1st Trimester Mask: Chronic HTN might be "hidden" early in pregnancy due to normal physiological vasodilation lowering the BP temporarily.
  • 3. Primary vs Secondary: 90% is Essential HTN. But if secondary, Renal disease makes up 80% of those secondary cases.
  • 4. The "Superimposed" Threat: 1 in 3 women (33%) with Chronic HTN will develop Superimposed Pre-Eclampsia. Watch out for new-onset proteinuria!
  • 5. Abruption Risk: Chronic hypertension is a classic and major risk factor for Placental Abruption.

⚖️ The Ultimate Comparisons

Top 5 high-yield differential concepts for MCQs

1. Screening vs. Diagnostic Prenatal Tests (Lec 17)
Feature Screening Tests Diagnostic Tests
Purpose Provides a measure of risk (e.g., 1 in 100 risk). Definitely confirms or rejects the diagnosis.
Safety Non-invasive, very safe, acceptable. Invasive, carries a small miscarriage risk (<0.5%).
Performance Good sensitivity, low false positive rate. High sensitivity and High specificity (Definitive).
Cost & Availability Cheap, widely available to all. Expensive, requires specialized operators.
Examples Combined Test, NIPT (cffDNA), Ultrasound. CVS, Amniocentesis, Cordocentesis.
2. Combined Test vs. Triple/Quadruple Test (Lec 17)
Feature Combined Test Triple / Quadruple Test
Timing First Trimester: 11 to 13+6 weeks. Second Trimester: 15 to 20 weeks.
Ultrasound Component Measures Nuchal Translucency (NT) + CRL. Dating scan only (No NT scan).
Serum Markers PAPP-A & β-hCG. Triple: Oestriol, hCG, AFP. Quad: Adds Inhibin A.
Advantages Highest detection rate (~90%). Early results allow surgical TOP. Less operator-dependent. Used if NT scan is missed.
3. CVS vs. Amniocentesis (Lec 17)
Feature Chorionic Villus Sampling (CVS) Amniocentesis
Timing After 11 weeks (Earlier diagnosis). After 15 weeks.
Sample Taken Trophoblast cells from placental villi. 15-20 mL Amniotic fluid containing fetal cells.
Specific Complication Confined Placental Mosaicism (<2% cases). Can detect fetal viral infections directly.
Miscarriage Risk < 0.5% (but 1% in twins). < 0.5%.
4. Atonic Uterus vs. Traumatic PPH (Lec 16)
Feature Atonic PPH ("Tone") Traumatic PPH ("Trauma")
Incidence Most common cause of PPH. Less common, follows difficult deliveries.
Abdominal Exam (Palpation) Uterus feels Flabby / Soft / Not contracted. Uterus feels Firm and well-contracted.
Bleeding Origin Placental bed inside the uterine cavity. Perineum, vagina, or cervix tears.
Primary Management Uterine massage, Uterotonics (Oxytocin, Misoprostol), Balloon Tamponade. Speculum examination under good light -> Suture repair (under anesthesia).
5. Mild/Moderate vs. Severe Pre-eclampsia (Lec 21)
Feature Mild to Moderate Pre-eclampsia Severe Pre-eclampsia
Blood Pressure Criteria 140/90 up to 159/109 mmHg. >= 160/110 mmHg.
Admission Policy Admit only if clinical concerns/high risk. Admit immediately.
BP Monitoring At least every 48 hours. Every 15-30 minutes until controlled.
Lab Monitoring Twice weekly (FBC, LFT, RFT). Three times a week (FBC, LFT, RFT).
Pharmacology Oral treatment to target <=135/85. Urgent IV Labetalol or Hydralazine. Evaluate for MgSO4.