Why do women develop blood clots during and after pregnancy?
Pregnancy and the postpartum period are times of massive changes in a woman’s body. During pregnancy, hormonal changes prepare the woman’s body to support and provide oxygen and nutrients to the growing fetus. These hormonal changes also affect blood clotting and blood flow. During pregnancy, the woman’s body produces more blood clotting substances in order to limit blood loss during labor and delivery. A side effect of this change is that blood clots in the veins are more likely to form. Patterns of blood flow in the woman’s body also change during pregnancy. The volume of blood increases to supply the fetus, and as the uterus grows it puts pressure on the veins in the pelvis, causing blood to flow back to the heart more slowly. Slow-flowing blood is more likely to form clots. The changes of pregnancy take place gradually over a period of months as the fetus grows. After the baby is born, these changes are rapidly reversed as the body returns to normal. These fast changes in blood flo
