Relationship between amniotic fluid and maternal blood nutrient levels

Abstract

To study the relationships between amniotic fluid and maternal blood nutrient concentrations, we obtained amniotic fluid and blood samples simultaneously from 76 pregnant women at around 17 weeks gestation. Folate and vitamin B-12 levels were measured by microbiological assay and radioassay, respectively, and zinc, copper and iron levels by atomic absorption spectrophotometry. Mean concentrations of plasma and red blood cell (RBC) folate and plasma copper of the pregnant women were 38 (+/- 1, SD), 1,501 (+/- 374) nmol/L, and 32.7 (+/- 4.8) mumol/L, respectively, all of which were higher than those of healthy non-pregnant controls (p < 0.001). Mean concentrations of plasma vitamin B-12, zinc and iron levels and RBC zinc were 320 (+/- 130) pmol/L, 12.2 (+/- 2.3), 21.7 (+/- 6.1) and 177 (+/- 30) mumol/L and these were similar to those of non-pregnant controls. Amniotic fluid folate, zinc, copper and iron concentrations were 21 (+/- 13) nmol/L, 1.4 (+/- 0.6), 1.7 (+/- 0.6) and 6.8 (+/- 2.1) mumol/L, respectively, which were significantly lower than plasma levels (p < 0.001). However, this relationship was reversed for vitamin B-12 (650 +/- 420 pmol/L). Significant correlations were found between amniotic fluid and maternal plasma and RBC for folate, and between amniotic fluid and maternal plasma for vitamin B-12 (p < 0.001). No such correlations were observed for zinc, copper and iron. There was no correlation between amniotic fluid and/or blood nutrient concentrations and pregnancy outcome including birth weight of infants.

Fetal and amniotic fluid iron homeostasis in healthy and complicated murine, macaque, and human pregnancy

“…In this study, we describe amniotic fluid and fetal iron homeostasis in healthy and complicated murine, rhesus macaque, and human pregnancy. In humans, iron concentrations in amniotic fluid were reported to be approximately 2-3 times lower than those in maternal plasma (31)(32)(33). In non-iron-supplemented pregnant women, iron concentrations in amniotic fluid do not correlate with those in maternal blood when assessed at 17 weeks of gestation (32).…”

“…In humans, iron concentrations in amniotic fluid were reported to be approximately 2-3 times lower than those in maternal plasma (31)(32)(33). In non-iron-supplemented pregnant women, iron concentrations in amniotic fluid do not correlate with those in maternal blood when assessed at 17 weeks of gestation (32). However, in iron-supplemented women in the second trimester, concentrations of iron in amniotic fluid were linearly correlated to concentrations in maternal blood (31), suggesting that iron in amniotic fluid can be increased through iron supplementation.…”

Analysis and identification of IS1548insertion targets inStreptococcus agalactiae

“…Zinc homeostasis is essential for bacteria because this element is indispensable for growth but becomes toxic at high concentrations. During neonatal meningitis, S. agalactiae has to cross subsequently several anatomic sites, which present very variable zinc concentrations: about 1.5 lM in the amniotic fluid, more than 14 lM in the blood, and 2.3 lM in the cerebrospinal fluid (Meret & Henkin, 1971;Tamura et al, 1994). Moreover, during infections, the host organisms react by increasing free zinc concentration, especially in their mucous membranes (McDevitt et al, 2011).…”