Notes on Cardiac, Renal, and Liver Disorders in Pregnancy

Cardiovascular Changes During Pregnancy

During pregnancy, several key cardiovascular parameters change:

  • Increased Parameters:
    • Cardiac Output: Increases, starting as early as 5 weeks, with >50% increase by 8 weeks. Peaks at 30 weeks during pregnancy, but is highest immediately after delivery.
    • CardiacOutput=HeartRate<br/>umber<em>of</em>timesStrokeVolumeCardiac Output = Heart Rate <br /> umber<em>of</em>times Stroke Volume
    • Heart Rate: Increases.
    • Stroke Volume: Increases.
    • Femoral Venous Pressure: Increases from 8 mmHg to 24 mmHg due to the gravid uterus compressing femoral vessels, leading to pedal edema, varicose veins, hemorrhoids, and increased risk of DVT/pulmonary embolism.
  • Decreased Parameters:
    • Peripheral Vascular Resistance: Decreases due to progesterone (a smooth muscle relaxant).
    • Blood Pressure: Both systolic and diastolic decrease, with a greater decrease in diastolic BP, especially in the second trimester and when supine.
  • Supine Hypotension Syndrome:
    • In late pregnancy, the gravid uterus compresses the inferior vena cava when the patient is supine, reducing venous return and cardiac output, which can cause maternal hypotension and fetal distress.
    • The best position for pregnant women is left lateral, followed by right lateral.
  • Unchanged Parameters:
    • Jugular Venous Pressure (JVP) / Central Venous Pressure (CVP): Remains normal.
    • Antecubital Venous Pressure: Remains normal.
    • Left Ventricular Ejection Fraction: Remains unchanged.

Important Single Liners

It's important to note the timing and extent of increase for heart rate, cardiac output, and stroke volume, as these might be asked in exams like NEET PG and FMG. (Refer to Williams 26th edition for a detailed table).

Clinical Indicators of Heart Changes

  • Heart Rotation:
    • The heart rotates upwards and outwards due to the growing uterus pushing the diaphragm, shifting the apex beat to the fourth intercostal space, 2.5 cm lateral to the midclavicular line.
    • This rotation can cause palpitations and left axis deviation on ECG and apparent cardiomegaly on X-ray (or due to benign pericardial effusion).
  • Pulse Rate: Increases due to increased heart rate.
  • Blood Pressure: Decreases.
  • JVP: Remains normal.
  • Heart Sounds:
    • S1 is loud with prominent splitting.
    • S2 is normal.
    • S3 is easily heard.
  • Murmurs:
    • Continuous murmur (mammary murmur) can be physiological.
    • Ejection systolic murmur physiological if less than grade 3/6.
    • Diastolic murmur requires ruling out heart disease, despite being physiological in 20% of females (according to Williams).

ECG and Chest X-Ray Findings

  • ECG: Axis deviation is normal, and nonspecific ST-T changes or ST depression may be seen.
  • Chest X-Ray: Apparent cardiomegaly or straightening of the left heart border may be observed.

Signs and Symptoms Indicating Heart Disease

While some symptoms are normal in pregnancy (palpitations, pedal edema), others suggest heart disease:

  • Paroxysmal Nocturnal Dyspnea (PND).
  • Orthopnea.
  • Nocturnal cough.
  • Hemoptysis.
  • Chest pain.
  • Syncope.
  • Progressively increasing dyspnea.

Signs indicating potential heart disease:

  • Cyanosis.
  • Clubbing.
  • Persistent neck vein distension (increased JVP).
  • Marked cardiomegaly on X-ray.
  • Loud S2 with prominent splitting.
  • Audible S4.
  • Ejection systolic murmur > grade 3/6.
  • Diastolic murmur.
  • Criteria for pulmonary hypertension.
  • Persistent tachycardia or arrhythmia.

Common Heart Diseases in Pregnancy

  • Most common: Rheumatic heart disease, specifically mitral stenosis.
  • Second most common: Congenital heart disease, specifically ASD.
  • Most common congenital valvular disease: Mitral valve prolapse.
  • Most common congenital cyanotic heart disease: Tetralogy of Fallot (TOF).
  • Worst prognosis/highest maternal mortality: Eisenmenger syndrome (30-50% mortality), often due to right ventricular failure and cardiogenic shock, typically around delivery or within one week postpartum.
  • Eisenmenger Syndrome: Secondary pulmonary hypertension from cardiac lesions like ASD, VSD, or PDA. Pulmonary artery pressure > 25mmHg25 mmHg (normal is 12−16mmHg12-16 mmHg).

Risk Factors for Heart Disease in Pregnancy (ACOG)

  • Race and ethnicity (highest in African American females).
  • Age >= 40 years.
  • Hypertension.
  • Obesity.

These factors increase cardiovascular-related mortality and morbidity.

Scoring Systems for Heart Disease

  • WHO Classification: Categorizes heart diseases into four classes based on morbidity and mortality risk, with Class IV being an absolute contraindication to pregnancy.
  • Karpreg Score: For acquired cardiac diseases.
  • Zahara Score: For congenital heart diseases.

Commonly, WHO classification along with NYHA classification is used.

WHO Classification (Class IV - Contraindications to Pregnancy)

  • Eisenmenger syndrome.
  • Pulmonary hypertension (any kind).
  • Marfan syndrome with aortic root dilatation > 4 cm.
  • Severe aortic dilatation.
  • Severe aortic coarctation.
  • Severe left heart obstruction (Left Ventricular Ejection Fraction < 30%).
  • Peripartum cardiomyopathy with residual defect.
  • Phantom surgery with residual defect.
  • NYHA Class III or IV (Dyspnea at less than ordinary activities or at rest).

NYHA Classification

  • NYHA Class I/II: Routine antenatal care, review cardiac status at 28-30 weeks, deliver at term.
  • NYHA Class III/IV: Advise MTP in the first trimester. If pregnancy continues, hospitalize, treat cardiac failure/pulmonary edema, and deliver at term.

Syndromes and Conditions with Associated Heart Diseases

  • Turner Syndrome: Bicuspid aortic valve (most common), coarctation of the aorta.
  • Down Syndrome: Endocardial cushion defect, ASD.
  • Congenital Rubella Syndrome: PDA.
  • Lithium Exposure: Ebstein anomaly (tricuspid regurgitation).
  • Pre-gestational Diabetes: Cardiovascular anomalies (most common: VSD; most specific: TGA), sacral agenesis (most specific anomaly overall).

Management of Heart Disease During Labor

  • Preferred Route: Vaginal delivery.
  • Wait for spontaneous labor; induction with PGE2 or oxytocin is safe. Avoid misoprostol (vasospasm).
  • Semi-recumbent position with left lateral tilt.
  • Epidural analgesia (pain relief) while avoiding hypotension.
  • Monitor pulse, BP, and lung sounds (crackles) every half-hour.
  • Judicious use of IV fluids to prevent heart failure.
  • Infective endocarditis prophylaxis only if indicated.
  • Second Stage: Shorten with outlet forceps (preferred over vacuum) to reduce maternal effort.
  • Third Stage:
    • Methylergometrine is contraindicated (tetanic contractions).
    • Oxytocin is safe.
    • Consider diuretics.
    • For PPH, use oxytocin and carboprost (except in intracardiac shunts or bronchial asthma).

Cesarean Section Indications

Reserved for obstetrical indications or:

  • Aortic aneurysm or dilated aorta > 4 cm (e.g., Marfan syndrome).
  • Severe symptomatic aortic stenosis.
  • Recent MI.
  • Need for valve replacement immediately postpartum.
  • Patient on warfarin at delivery or within two weeks (risk of PPH and fetal intracranial hemorrhage).

Anesthesia Considerations

  • Epidural anesthesia is generally preferred.
  • General or regional anesthesia (CASH mnemonic):
    • C: Intracardiac shunt.
    • AS: Severe aortic stenosis.
    • H: Pulmonary hypertension.

Management of Heart Failure During Labor

  • Suspect heart failure with heart rate > 100 bpm and respiratory rate > 24 breaths/min.
  • Manage with aggressive diuresis, beta-blockers, and digoxin.
  • Precipitating factors: Chronic hypertension with superimposed preeclampsia, obesity, high BP.

Infective Endocarditis Prophylaxis

Not routine; only indicated for:

  • Cesarean section.
  • Prosthetic valve or prosthetic material used in valve repair.
  • History of prior endocarditis.
  • Unrepaired cyanotic congenital heart disease or repair within the past six months or with residual defects.

Drug of choice: ampicillin + gentamicin. Alternative: vancomycin + gentamicin (if penicillin allergy).

Cardiac Procedures During Pregnancy

  • Elective surgery is avoided due to fetal risk with cardiopulmonary bypass.
  • Emergent cases (e.g., mitral stenosis with intractable pulmonary edema or NYHA Class III/IV early in pregnancy): Balloon valvuloplasty (preferred, best in 2nd trimester). Valve replacement is generally avoided.
  • Mitral Valve Area: Surgical correction advised pre-conception if area < 1.5cm21.5 cm^2. Fetal growth restriction occurs when area < 1cm21 cm^2.

Peripartum Cardiomyopathy

  • Cardiac failure after 35 weeks of pregnancy or within five months postpartum, with no identifiable cause or pre-existing heart disease. Diagnose with Echo showing EF < 45%
  • Coexisting Factors: PIH, increased SFLT1, and 16k Dalton Prolactin fragment (vasoinhibin).
  • Treatment: Bromocriptine.
  • Mortality: 5-10%; Recovery: 50% within six months.
  • Recurrence: 20% in subsequent pregnancies; higher if incomplete recovery.
  • Peripartum cardiomyopathy with residual effects is an absolute contraindication to pregnancy.

Anticoagulants in Pregnancy

  • Shift from warfarin to heparin at 36 weeks (either LMWH or UFH).
  • 36 hours before delivery, switch to unfractionated heparin (UFH) due to shorter half-life and stronger protamine antagonism.
  • Stop UFH 6-8 hours before vaginal delivery; restart 6 hours after vaginal delivery or 6-12 hours after cesarean section.

Renal Disorders in Pregnancy

  • Glycosuria is normal due to decreased renal tubular absorption. Persistent glycosuria > +1 or single reading > +2 warrants oral glucose testing.
  • Proteinuria >= +2 or >= 300 mg in 24 hours indicates preeclampsia.
Asymptomatic Bacteriuria
  • >= 10510^5 bacteria/mL without symptoms.
  • Common cause: E. coli.
  • Risk factors: Diabetes, sickle cell trait.
  • Risks: Preterm labor, pyelonephritis (25% if untreated).
  • Screening: Urine culture and sensitivity at first antenatal visit (or dipstick nitrite method in low-prevalence areas).
  • Treatment: Amoxicillin, ampicillin, cephalosporin, or nitrofurantoin at bedtime for 10 days. If treatment failure, use nitrofurantoin for 21 days. For recurrent infections, use nitrofurantoin 100 mg at bedtime for the rest of pregnancy.
Acute Pyelonephritis
  • Most common serious nonobstetrical medical complication of pregnancy and leading cause of septic shock in pregnancy; associated with increased incidence of cerebral palsy in newborns.
  • More common in the second half of pregnancy, in nulliparous and young females.
  • Unilateral (right side more common).
  • Presentation: Fever, chills, lumbar pain.
  • Management:
    • Hospitalize.
    • Obtain blood and urine culture.
    • CBC, electrolytes, serum creatinine (repeat after 48 hours).
    • Chest x-ray (if dyspnea).
    • Monitor vital signs and urine output.
    • IV fluids to maintain urine output >= 50 mL/hour.
    • IV antibiotics (ampicillin and gentamicin).
    • Switch to oral antibiotics when afebrile for 7-10 days (some recommend 10-14 days).
    • Repeat urine culture 1-2 weeks after completing antibiotics.

Liver Diseases in Pregnancy

  • Acute Fatty Liver of Pregnancy (AFLP) and Intrahepatic Cholestasis of Pregnancy (ICP) are crucial.
  • Differentiate AFLP, HELLP syndrome, hepatitis, and ICP.
Acute Fatty Liver of Pregnancy (AFLP)
  • Most common cause of liver failure in pregnancy; fatty infiltration of hepatocytes without inflammation or necrosis.
  • Autosomal recessive disorder.
  • Etiology:
    • Fetal LCHAD deficiency (long-chain hydroxyacyl-CoA dehydrogenase).
    • Maternal genetic mutation affecting mitochondrial fatty acid oxidation.
  • Risk factors: Previous AFLP, preeclampsia/HELLP, male fetus, multiple gestation.
  • Presentation: Jaundice, abdominal pain, nausea/vomiting, hypoglycemia, hepatic encephalopathy (60%).
  • Complications: Multiple organ dysfunction, acute renal failure (60%), coagulation failure, pancreatitis, diabetes insipidus.
  • Hypertension +/- proteinuria may be associated; 20-40% associated with HELLP.
  • Management: Immediate termination of pregnancy, irrespective of gestational age.
Intrahepatic Cholestasis of Pregnancy (ICP)
  • Reversible condition in the third trimester due to increased estrogen levels.
  • Incomplete clearance of bile acids, leading to accumulation in plasma and mildly deranged LFTs.
  • Etiology: Increased estrogen levels, genetic predisposition, and multi-fetal pregnancy.
  • Presentation: Pruritus (generalized, worse at night, palms and soles), jaundice (10-15%, 1-4 weeks after pruritus).
  • Diagnosis: Bile acids > 10 mmol/L, bilirubin < 6, AST/ALT < 2x normal.
  • Fetal Risks: Stillbirth, preterm birth, meconium-stained amniotic fluid, respiratory distress syndrome.
  • Management: Termination at >= 37 weeks, induction of labor, ursodeoxycholic acid for the mother.
  • Recurrence: 45-70%; contraindicated with oral combined pills.
Differentiation of Liver Disorders

(Refer to table for detailed differentiation between HELLP, AFLP, hepatitis, and hyperemesis gravidarum based on onset, clinical features, hypertension, AST, bilirubin, creatinine, hematocrit, platelet count, and DIC.)

Viral Hepatitis
  • Screening for HBsAg at the first antenatal visit.
  • Vertical transmission rate: 10-20%.
  • Check the partner for HBsAg and anti-HBsAg.
  • Check pregnant female's HBeAg at 36 weeks. If positive, the vertical transmission rate increases to 90%.
  • If HBeAg is positive or viral load >= 10610^6, administer tenofovir to the mother.
  • Infant receives hepatitis B immunoglobulin and the first dose of the hepatitis B vaccine immediately after birth, followed by doses at one and six months. Test the baby for HBsAg and anti-HBs at nine and 18 months.
  • Maternal HB infection is not a contraindication to breast feeding or vaginal delivery. If mother has HBe antigen positive or if she had a high viral load, then there are ten percent chances that vertical transmission would occur.