Obstetrics and Gynecology - A. M. Gromova 2000

Changes in the female body during pregnancy
Hematological changes during pregnancy

As noted earlier, a normal Pregnancy is accompanied by an increase in circulating Blood volume. This expansion is driven by increases in both plasma volume and the mass of formed blood elements.

The number of circulating erythrocytes increases progressively throughout pregnancy. This is stimulated by Erythropoietin, which is synthesized by renal Tissues under METABOLISM/18.html">The Influence of progesterone. Enhanced hematopoiesis and the resulting increase in the absolute erythrocyte count lead to a higher total oxygen-carrying capacity of the blood, helping to meet the expectant mother's increased oxygen demand by accelerating Oxygen transport through the bloodstream.

However, the capacity of Hematopoietic Organs lags behind The rate of circulating fluid expansion; consequently, pregnancy induces autohemodilution, which manifests as decreased Hemoglobin concentration and red blood Cell counts per unit of blood volume. This constitutes a major factor contributing to The Development of anemia.

Leukocyte counts vary widely during pregnancy, ranging from 5х109/L to 12х109/L. On average, the count rises slightly, primarily due to an increase in neutrophilic granulocytes.

Platelet counts do not change significantly during pregnancy.

Starting from early pregnancy (12 weeks of gestation), There is a tendency toward enhanced blood coagulability. Plasma fibrinogen levels rise, with the most pronounced increase occurring during the final two months of pregnancy. From the 6th month of gestation onward, other shifts within the hemostatic system become apparent: the recalcification time shortens, plasma tolerance to heparin increases, and clot retraction and formation rates accelerate. Fibrinolytic activity decreases, particularly prior to delivery.

These shifts in the balance between procoagulant and anticoagulant blood properties toward hypercoagulability serve as a vital adaptive mechanism to prepare the body for blood loss during childbirth.



Last update: 08/08/2026

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