The physiologic anaemia of pregnancy is BEST explained by which mechanism?

• A Bone marrow suppression by rising progesterone levels
• B Plasma volume expansion proportionally greater than the rise in red cell mass ✓
• C Shortened red cell survival from splenic sequestration
• D Increased iron loss through placental transfer

Explanation

Plasma volume rises by roughly 40 to 50 percent while red cell mass rises by only about 20 to 30 percent, producing a fall in haemoglobin and haematocrit that reaches its nadir around 30 to 34 weeks. This dilutional picture lowers blood viscosity and may benefit placental perfusion. Red cell mass actually increases, marrow is stimulated rather than suppressed, and placental iron transfer does not deplete maternal haemoglobin in this manner.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.