Obstetrics Pg No 363 -372

Anemia in Pregnancy: Part 2

• Mild-Moderate Anemia: Treatment involves oral iron therapy with 2 IFA tablets/day. This should continue throughout pregnancy and for 180 days post delivery to replenish iron stores.
• Adequate Response to Oral Iron: Hb levels should increase by ≥ 19% after one month of treatment. For compliant patients, the dose of 2 tablets/day should be maintained. Inadequate responses require further assessment and may necessitate a switch to parenteral iron therapy.
• Reticulocyte Count: This is a preferred measure for assessing response to iron therapy as it indicates new red blood cell production.
• Therapeutic Decision Making: Iron supplementation is adjusted based on gestational age and the patient's response to treatment.

Therapeutic Decision Making for Anticoagulation During Pregnancy

• Warfarin: A dose of < 5mg/day can be continued with aspirin. For doses ≥ 5mg/day, switch to low molecular weight heparin (LMWH) plus aspirin.
• Delivery in Patients on Warfarin: Warfarin should be discontinued. Cesarean section is recommended to minimize the risk of fetal intracranial hemorrhage. Vitamin K should be administered to the mother and baby.

Disala Syndrome

• This syndrome is a rare but serious condition caused by warfarin use in pregnancy.

Fetal Anomalies Associated with Warfarin Use

• Chondrodysplasia: Features include a depressed nasal bridge and stippled epiphysis.
• Cataracts

Central Nervous System (CNS) Defects Associated with Warfarin Use

• Microcephaly: Reduced head size.
• Hydrocephalus: Abnormal accumulation of cerebrospinal fluid in the brain.
• Dandy-Walker malformation: This affects brain structure and can cause hydrocephalus.

Anti-epileptic Drugs in Pregnancy

• Teratogenicity: Valproic acid has the highest teratogenicity potential, followed by phenytoin, phenobarbital, carbamazepine, lamotrigine, and lastly levetiracetam.
• Valproic Acid Effects: Causes neural tube defects, CNS malformations, and urinary tract deformities.
• First Epileptic Attack in Pregnancy: Levetiracetam and lamotrigine are recommended.
• Epilepsy in Pregnancy: Continue the same medication at the lowest effective dose. Folic acid supplementation is essential.
  • ≥ 1 month before conception: 0.4 mg/day
  • After conception: 1 mg/day

RBC Indices and Anemia Diagnosis

• Mentzer Index: Used to differentiate between Iron Deficiency Anemia (IDA) and Thalassemia.
  • < 13: Thalassemia

  • 13: IDA

• Mean Corpuscular Volume (MCV): Used to classify anemias based on red blood cell size.
  • Microcytic Anemia (< 75 fL): IDA, Thalassemia, Sideroblastic Anemia, Lead poisoning, Anemia of chronic disease
  • Macrocytic Anemia (> 100 fL): Vit B12 deficiency, Folic acid deficiency, Anemia of liver disease, Thyrotoxicosis
• Serum Ferritin: The most sensitive and earliest indicator of iron stores.
  • Normal: 34-37%
  • IDA: < 30%
• Iron Study Parameters:
  • Serum Ferritin:

    • 100: Normal iron stores

    • < 20: Depletion of iron stores
    • < 40 mcg/dL: IDA
  • Serum Iron: < 40 mcg/dL: IDA
  • TIBC: 325-400 mcg/dL

    • 410: IDA

  • Transferrin Saturation:
    • Normal: 25-50%
    • < 10%: IDA
• IDA vs Anemia of Chronic Disease: Serum hepcidin is useful for differentiation. Bone marrow biopsy is the gold standard method but invasive.

Parenteral Iron Therapy

• Indications: Non-compliance to oral therapy, intolerance to oral iron, and specific gestational age considerations.
• Parenteral Iron Preparations: Iron dextran (1st generation), iron sucrose (2nd generation), ferric carboxy maltose (3rd generation).
• Route: Intravenous
• Dose: Calculated using the Ganzoni formula.
• Infusion Rate: Start with a slow rate (15-20 drops/min) and gradually increase to 80-90 drops/min if no allergic reaction occurs.

Blood Transfusion

• Indications: Thalassemia major, heart failure, acute hemorrhage, Hb < 5, Hb 5-6.9 at >34 weeks, bone marrow failure.
• Contraindications: 1st trimester, hemochromatosis, thalassemia major.
• Blood Product: One packed cell transfusion/day can increase Hb by 1%.
• Exceptions: Hemorrhage > 1g%/day and congestive heart failure.

Anemia in Pregnancy: Part 1

• Previous Pregnancy: Relevant information includes previous use of parenteral iron and blood transfusions.

Physical Examination

• Pallor: Sites assessed for pallor include conjunctiva, oral mucosa, and nail beds.
• Nails: Koilonychia (distorted nails), platonychia (flat nails), and yellowish discoloration (hemolytic anemia, IDA).
• Glossitis/Cheilosis: Indicates folic acid deficiency.
• Jugular Venous Pressure (JVP): Normally elevated in pregnancy, but abnormal elevations suggest congestive heart failure.

  • 8 cm of H₂O (3 cm above clavicle) indicates heart failure.

• Leg Ulcers: Suggestive of sickle cell anemia.
• Lymph Node Enlargement: To rule out chronic diseases such as tuberculosis and malignancy.

Laboratory Diagnosis

• Indian Guidelines: Hemoglobin levels should be checked four times during each antenatal visit. Screening threshold for anemia: Hb < 11 gm%.
  • 1. Complete Blood Count + Reticulocyte count
  • 2. Peripheral smear
  • 3. Hb electrophoresis (If sickle cell anemia or thalassemia is suspected)
• International Guidelines: Hemoglobin levels should be checked twice: at the first antenatal visit and again between 24-28 weeks of gestation.

Management of Heart Disease

Intrapartum Management (Vaginal Delivery)

• Spontaneous labor and induction of labor (as needed) are considered.
• For a ripe cervix, vaginal delivery is the preferred route.
• Prophylactic use of forceps/vacuum may be considered to shorten labor stages and reduce maternal effort.
• Monitor maternal and fetal heart rate, as well as fluid input and output.
• Semi-recumbent position with left lateral tilt is recommended.
• Restrict IV fluids to 75mL/hr.
• Epidural analgesia may be used.
• Limit pelvic exams to prevent infective endocarditis.
• Ampicillin + gentamicin is given when membranes rupture.

Postpartum Management

• Active Management of the Third Stage of Labor (AMSTL) is recommended.

Indicators for Cesarean Section

• Aortic Lesions: Increased risk of aortic dissection during vaginal delivery.
  • Severe aortic stenosis (AS)
  • Aortic aneurysm
  • Marfan syndrome with aortic root dilatation
  • Coarctation of aorta
• Patients on Warfarin: Within 2 weeks of delivery, there's an elevated risk of postpartum hemorrhage (PPH) and fetal intracranial hemorrhage.
• Refractory Heart Failure

Anesthesia

• Neuraxial anesthesia (epidural) is the preferred type for patients with heart disease.
• General Anesthesia (GA): Indicated for patients with:
• Intracardiac shunt
• Severe AS
• Heart Outcome/Complications (HOCT)

Postpartum Hemorrhage (PPH) in Heart Disease

• Oxytocin is the drug of choice for managing PPH.
• Methylergometrine can be considered as an alternative.

Preconceptional Counseling

• Ventricular Septal Defect (VSD): This has the highest risk of recurrence.
• Investigations: ECG and echocardiogram are essential.
• Surgery: If needed, should be performed before conception.

Indicators of Heart Disease

• Symptoms:
  • Progressive dyspnea
  • Orthopnea
  • Paroxysmal nocturnal dyspnea
  • Hemoptysis
  • Chest pain
  • Non-dependent edema/anasarca

Most Common Heart Disease (HD) in Pregnancy

• Rheumatic heart disease (especially mitral stenosis - ms) is the most common.
• Atrial septal defect (ASD) is the most common congenital HD.
• Tetralogy of Fallot (TOF) is the most common cyanotic HD.
• Mitral valve prolapse (MVP) is the most common congenital valvular HD.
• Eisenmenger syndrome: This carries the highest risk of maternal mortality.

Death due to Right Ventricular Failure

• Most common cause of death: Right ventricular failure.
• Time of death: During labor or within 1 week of delivery.
• Pregnancy is contraindicated in this condition.
• Mitral stenosis (mS) is the most frequent cause of maternal mortality.

WHO Class 4 Heart Disease

• Highest possibility of death due to pregnancy.
• Pregnancy is contraindicated.
• Medical termination of pregnancy (MTP) is advised.

Associated Conditions

• Pulmonary hypertension: Primary (1°) or secondary (2°)
• Severe mitral stenosis (mS)/aortic stenosis (AS)
• Left ventricular ejection fraction (LVEF) < 30%
• Chest X-ray: Marked cardiomegaly
• Arrhythmia

Heart Diseases with Good Prognosis in Pregnancy

• Congenital Heart Disease (CHD)
• Repaired VSD/ASD
• Corrected TOF, PDA, MVP

Heart Disease Prognosis in Pregnancy

• Worsens:
  • Stenotic lesions: Increased heart rate reduces the time for atrial blood to enter ventricles.
  • Symptom: Dyspnea on exertion
  • Management: Limit physical activity, and prescribe beta-blockers
• Improves:
  • Regurgitant lesions: Decreased diastolic blood pressure (DBP) reduces pressure gradient between chambers and decreases backflow of blood.
  • Acyanotic HD

HEART DISEASES IN PREGNANCY

Physiological Changes:

• Increased Parameters:
  • Cardiac Output (CO):
    • CO = Stroke Volume (SV) x Heart Rate (HR)
    • Increase begins at 5 weeks
    • Maximum at 28-32 weeks
    • Returns to normal: 10 days post-delivery
  • Femoral Venous Pressure:
    • Compression of inferior vena cava (IVC) by uterus
    • Peripheral pooling of blood
    • Increased risk: Varicose veins, vulval varicosities, hemorrhoids
• Decreased Parameters:
  • Peripheral Vascular Resistance (PVR):
    • Progesterone and Relaxin act as smooth muscle relaxants.
  • Blood Pressure:
    • Systolic BP
    • Diastolic BP: Maximum decrease
    • Mean Arterial Pressure: Maximum decrease
• Unchanged Parameters:
  • JVP
  • Pulmonary Capillary Wedge Pressure (PCWP)
  • Left Ventricular Ejection Fraction (LVEF)
• Best Position for Pregnant Women: Left Lateral > Right Lateral

Normal Pregnancy Symptoms:

• Easy fatiguability
• Decreased exercise tolerance
• Dyspnea on exertion
• Peripheral dependent edema

Clinical Indicators:

• Heart rate: Increased
• Pulse rate: Increased
• BP: Decreased
• JVP: Normal
• Heart Position Changes:
  • Heart is displaced upwards and outwards towards the left.
  • Apex beat: 4th intercostal space, 2.5 cm lateral to the mid-clavicular line.
  • Heart Sounds:
    • S1: Louder and more prominent split
    • S2: Normal
• S3: Easily audible
• Murmurs: Continuous/mammary murmur, ejection systolic murmur grade 2-3 (involving the aortic and pulmonary valves).

Drugs in Pregnancy

Antibiotics

• Safe: Cephalosporins, ampicillin, metronidazole, penicillin
• In the 1st Trimester:
  • Nitrofurantoin (DOC for asymptomatic bacteriuria)
  • Fluconazole
  • Trimethoprim
• Note:
  • G6PD deficiency: Avoid nitrofurantoin and sulphamethoxazole
  • Doxycycline: Tetracycline can be used only with a strong indication.
• Throughout Pregnancy: Avoid fluoroquinolones, aminoglycosides, and tetracyclines.

Anticoagulants

• Warfarin:
  • Advantages: Crosses the placenta
  • Disadvantages: Teratogenic, increases risk of postpartum hemorrhage and fetal intracranial hemorrhage when used at delivery time.
• Low Molecular Weight Heparin (LMWH):
  • Advantages: Does not cross the placenta
  • Disadvantages: Low potency anticoagulant
• Target Values:
  • Warfarin: INR 2.5-3
  • LMWH: Factor Xa 0.8-1.2
• Teratogenicity of Warfarin: Depends on:
  • Dose: ≥ 5mg/day (Teratogenic dose)
  • Gestational age: Maximum teratogenicity in the 1st trimester, particularly at 7-9 weeks.
• Note: LMWH can be replaced by unfractionated heparin (UFH) 1 week prior to delivery due to faster action and reversibility.

Valve Replacement

• Mechanical valve replacement: Anticoagulant + Aspirin (continue until 36 weeks)
• Bioprosthetic valve replacement: Aspirin only