# FETAL BLOOD VOLUME DYNAMICS AND CONTROL

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 1994 · $187,401

## Abstract

The proposed studies are designed to explore the dynamics and
control of blood volume in the chronically catheterized sheep fetus.  The
long-term objective is to generate an integrated understanding of the
various factors which are important in determining fetal blood volume
under normal as well as aberrant conditions.  The background to the
proposed studies is that the regulation of blood volume in fetus appears
dramatically different from that in the adult because fluid movements
within the fetus (eg, transcapillary, swallowing, urine flow, lymph flow)
are roughly an order of magnitude greater than in the adult (relative to
body weight).  In addition, fluids move by 3 pathways which are not
present in the adult (ie, across the placenta, out of the fluid filled
lungs, and across the intramembranous pathway) so blood volume regulation
in the fetus is more complex than in the adult.  Our proposed studies are
aimed at exploring cardiovascular, renal and placental mechanisms which
control the movement of fluid into and out of the fetal vascular
compartment.  We will test the following hypotheses: 1) the fetus, when
subjected to a long-term loss of blood, can produce only a minor
augmentation of its red cell production rate but can rapidly produce
large quantities of new plasma proteins; 2) a 3-5 fold elevation in fetal
lactate concentration will elevate blood volume and produce severe fetal
edema and/or polyhydramnios; and 3) elevations in plasma lactate will
produce more extensive fetal edema and/or hydramnios in anemic fetuses.
These studies will help us understand disease states such as
erythroblastosis fetalis, polyhydramnios, and hydrops fetalis in humans.
We will determine the mechanisms of isotonic fluid transfer from the
fetus to its mother land determine the changes in placental permeability
which occur with short-term vascular volume loading of isotonic fluid
into the fetus.  In addition, we will explore the developmental changes
in the filtration coefficient of the placenta and determine whether
selected hormones alter this placental permeability parameter.  These
studies will provide fundamental information which is needed in order to
understand what factors are involved in the control of the distribution
of fluid between the fetus and its mother and may provide a basis for the
treatment of oligohydramnios.  Collectively, results generated from the
proposed studies will significantly contribute to our understanding of
the regulation of blood volume in the ovine fetus.  This, in turn, may
lead to better treatment of fetal and neonatal disorders, thereby
reducing fetal and neonatal morbidity and mortality.

## Key facts

- **NIH application ID:** 2197989
- **Project number:** 5R01HD020295-10
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **SAM.gov UEI:** UYTTZT6G9DT1
- **Principal Investigator:** ROBERT A BRACE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $187,401
- **Award type:** 5
- **Project period:** 1984-12-01 → 1995-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2197989

## Citation

> US National Institutes of Health, RePORTER application 2197989, FETAL BLOOD VOLUME DYNAMICS AND CONTROL (5R01HD020295-10). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2197989. Licensed CC0.

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