PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 15914042

Pre-delivery changes in amniotic fluid volume and composition in sheep.

Robert A Brace·Cecilia Y Cheung
View original source ↗Export metadata ↓

Abstract

OBJECTIVE: To determine the changes in amniotic fluid (AF) volume and solute concentrations during the last 3 weeks of gestation in fetal sheep with a ligated urachus. METHODS: AF volume as well as solute concentrations of AF, fetal urine, fetal blood, and maternal blood were measured serially over the last 24 days of gestation in chronically catheterized fetal sheep. Statistical analyses included regression analysis and analysis of variance (ANOVA). RESULTS: Delivery occurred at 145.5 +/- 1.1 (SE) days (n = 11 animals). AF volume averaged 913 +/- 46 mL (n = 119 determinations total from 11 animals) and was unchanged with time when analyzed against either gestational age (P = .9) or time prior to delivery (P = .81). Amniotic osmolality, sodium, chloride, glucose, and calcium concentrations decreased as gestation progressed, while potassium and lactate concentrations increased. Only amniotic lactate underwent a pre-delivery increase in concentration. From multivariate regression, AF solute concentrations correlated positively with fetal blood and urine concentrations and negatively with gestational age. CONCLUSIONS: In fetal sheep with a ligated urachus, AF volume does not decrease prior to labor and delivery. This differs from the sharp pre-delivery decrease in AF volume that occurs in rats, mice, and pigs and is similar to the relatively constant AF volume in humans, baboons, and monkeys. Further, pre-delivery changes in AF lactate concentration may reflect the consequences of a low AF volume. Regression analysis suggests that fetal blood and urine independently contribute to AF solute concentrations and that gestational age-specific changes in intramembranous transport also may contribute.

Explore related subjects

Amniotic FluidAnimalsFemaleGestational AgeLigationPregnancyPregnancy, AnimalSheepUrachusJournal ArticleResearch Support, N.I.H., ExtramuralResearch Support, U.S. Gov't, P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Robert A Brace, Cecilia Y Cheung. 2005. Pre-delivery changes in amniotic fluid volume and composition in sheep.. https://doi.org/10.1016/j.jsgi.2005.04.004

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Perinatal outcomes of pregnancies with borderline amniotic fluid index.

OBJECTIVE: Our aim was to determine whether a borderline amniotic fluid index observed during antepartum testing confers a significant risk of adverse perinatal outcome. METHODS: Between April 2001 and May 2005, uncomplicated gestations with a singleton non-anomalous fetus, who underwent weekly monitoring of amniotic fluid index (AFI) until delivery during the last trimester and who gave birth at our hospital, were identified for our study. Normal amniotic fluid volume and borderline amniotic fluid were defined as AFI of >10 and <24 cm and >5 and <10 cm, respectively. The groups were compared on maternal data, mode of delivery and perinatal outcomes such as fetal distress, intrauterine growth restriction and meconium fluid. RESULTS: A total of 90 cases were identified as borderline amniotic fluid and 277 cases as normal AFI. We observed significant increased incidences of admission to neonatal intensive care unit, intrauterine growth restriction, meconium-stained amniotic fluid, intrapartum fetal distress in the group with borderline amniotic index (P < 0.05). CONCLUSIONS: A borderline amniotic fluid index observed in antepartum testing during the last trimester carries an increased risk of adverse perinatal outcomes. These patients should be followed up carefully during the antepartum and intrapartum period.

Amniotic Fluid↗
PubMed2007

Isolation of amniotic stem cell lines with potential for therapy.

Stem cells capable of differentiating to multiple lineages may be valuable for therapy. We report the isolation of human and rodent amniotic fluid-derived stem (AFS) cells that express embryonic and adult stem cell markers. Undifferentiated AFS cells expand extensively without feeders, double in 36 h and are not tumorigenic. Lines maintained for over 250 population doublings retained long telomeres and a normal karyotype. AFS cells are broadly multipotent. Clonal human lines verified by retroviral marking were induced to differentiate into cell types representing each embryonic germ layer, including cells of adipogenic, osteogenic, myogenic, endothelial, neuronal and hepatic lineages. Examples of differentiated cells derived from human AFS cells and displaying specialized functions include neuronal lineage cells secreting the neurotransmitter L-glutamate or expressing G-protein-gated inwardly rectifying potassium channels, hepatic lineage cells producing urea, and osteogenic lineage cells forming tissue-engineered bone.

Amniotic Fluid↗