Pharmacology of Obstetrics
Anemia in pregnancy (Hb <11 g/dL) is the most common medical disorder, with iron deficiency accounting for >90% of cases. Early detection and treatment prevent maternal and fetal complications.
Definition & Severity (WHO)
| Severity | Hb (g/dL) |
|---|---|
| Mild | 10–10.9 |
| Moderate | 7–9.9 |
| Severe | <7 |
| Very Severe | <4 |
Physiological vs. Pathological Anemia
Plasma ↑50%, RBC mass ↑25% → hemodilution → normal Hb ~10–11 g/dL
Pathological: actual RBC/Hb deficit
Types & Causes
| Type | Causes | Blood Picture |
|---|---|---|
| IDA | Diet, blood loss, hookworm | Microcytic, hypochromic |
| Megaloblastic | Folate/B12 deficiency | Macrocytic |
| Hemolytic | Sickle, malaria | Normocytic, ↑retic |
| Chronic disease | Infection | Normocytic |
Clinical Features
Symptoms
- Fatigue, SOB, palpitations
- Headache, dizziness
Signs
- Pallor (conjunctiva, tongue)
- Tachycardia, flow murmur
- Brittle nails, glossitis
Investigations
| Test | Finding |
|---|---|
| Serum ferritin | <15 µg/L = IDA |
| PBF | Microcytic, hypochromic |
| Stool | Hookworm ova |
Management
Oral Iron (Mainstay)
- Ferrous sulfate 200 mg TDS (60 mg Fe)
- Continue 3 months after Hb normal
Parenteral Iron
- Iron sucrose IV
- Ferric carboxymaltose (single dose)
Blood Transfusion
- Hb <6 g/dL + symptoms
- Goal: Hb ≥8–9 g/dL
Prevention
- 60 mg Fe + 400 µg folate daily from 14w
- Screen at booking, 28w, 36w
- Deworming (Mebendazole after 1st trimester)
Key Takeaways
- Hb <11 = anemia; IDA >90%
- Microcytic, hypochromic = IDA
- Ferritin <15 = gold standard
- Oral iron + folate first-line
- Transfusion if Hb <6 + symptoms
- Complications: PPH, IUGR, heart failure
Conclusion
Anemia is preventable and treatable. Routine supplementation and screening save lives.
Anemia in pregnancy is silent but deadly — screen and treat early.