In plain words
Plasma volume expansion is the increase in the liquid part of your blood during pregnancy. It rises by about half by the end of pregnancy. This happens to support the baby and the placenta. The extra fluid can cause some swelling in the hands, feet, and face. It can also make you feel dizzy when you stand up quickly, and it can make your heart work harder. It is normal and not a sign that something is wrong. It settles after birth, when fluid shifts back. Tell your provider about sudden or severe swelling, since that needs checking.
The deeper version
Plasma volume rises by about 40 to 50 percent over gestation, with red cell mass increasing less, producing and a fall in hematocrit (Hytten, 1985). The mechanism involves progesterone-driven vasodilation, sodium retention through the renin-angiotensin-aldosterone system, and the metabolic cost of placentation. Plasma volume expansion explains a substantial part of the hemodynamic changes of pregnancy, including increased cardiac output and reduced systemic vascular resistance early in gestation. Its return to baseline postpartum shifts fluid and can contribute to and . Excess or sudden edema requires assessment for .
Where it comes up
- Exhaustion in the first trimesterPregnancy: Your Body
- Drinking enough waterPregnancy: Eating
- Swelling after birthPostpartum: Your Body
- Swelling: feet, ankles, hands, facePregnancy: Your Body
- What to eat in pregnancy: the short versionPregnancy: Eating
What mothers here say about plasma volume expansion
No one has posted under this term yet.
Sources
- Hytten F — Blood volume changes in normal pregnancy. Clinical Haematology, 1985
- Hytten F, Chamberlain G (editors) — Clinical Physiology in Obstetrics (1980)