This patient has Iron Deficiency Anemia (IDA) of pregnancy, indicated by:

• Low Hb: \(7.8\,\text{g/dL}\) (normal in pregnancy \(\geq 11\,\text{g/dL}\))
• Low MCV: \(72\,\text{fL}\) (microcytic; normal \(80{-}100\,\text{fL}\))
• Low ferritin: \(6\,\text{ng/mL}\) (normal \(>12\,\text{ng/mL}\))

With adequate oral iron supplementation (elemental iron \(100{-}200\,\text{mg/day}\)):

• Reticulocyte response begins in 3–5 days
• Hemoglobin rises approximately \(1\,\text{g/dL}\) per week or \(\approx 2\,\text{g/dL}\) in 3–4 weeks
• Full correction takes 6–8 weeks
• Iron stores replenished over 3–6 months

If Hb does not rise by \(\geq 1\,\text{g/dL}\) after 4 weeks, consider: non-compliance, malabsorption, wrong diagnosis, or continued blood loss. IV iron is indicated if oral not tolerated or \(<28\) weeks with severe anemia.