TY - JOUR
T1 - Thyroxine in human amniotic fluid
AU - Sack, Joseph
AU - Fisher, Delbert A.
AU - Hobel, Calvin J.
AU - Lam, Robert
N1 - Funding Information:
From the Departments of Pediatrics and Obstetrics and Gynecology and the Division of Endocrinology, UCLA-Harbor General Hospital. Supported by United States Public Health Service Grant HD-O4270 from the National Institute of',Child Health and Human Development of the National Institutes of Health, Bethesda, Md. *Reprint address: Division of Endoerinology, Harbor General Hospital, 1000 IV.. Carson St., Torrance, Calif. 90509.
PY - 1975/9
Y1 - 1975/9
N2 - Total and free T3 and T4 concentrations were measured in human amniotic fluid and in fetal and maternal blood. Before 20 weeks, the mean AF-T4 level was 0.24 μg/dl; there is a progressive increase in concentration with gestational age. At term, the mean AF total T4 level was much less (0.64 μg/ dl) than in fetal or maternal serum (9.3 and 11.3 μg/dl, respectively). Most of the T4 (99.4%) in AF is protein bound, presumably to TBG as in serum, but the mean FT4 concentration in AF at term (4.13 ng/dl) was significantly greater than the levels in fetal or maternal serum (2.67 or 2.56 ng/dl, respectively). The mean TBG level in AF at term was 0.26 mg/dl. T3 was not measurable in AF (<15 ng/dl). There were no significant correlations between the total or free T4 concentrations in maternal or fetal sera and in amniotic fluid. Thus AF thyroid hormone concentrations in the euthyroid fetus do not reliably reflect fetal serum T4 or T3 concentrations.
AB - Total and free T3 and T4 concentrations were measured in human amniotic fluid and in fetal and maternal blood. Before 20 weeks, the mean AF-T4 level was 0.24 μg/dl; there is a progressive increase in concentration with gestational age. At term, the mean AF total T4 level was much less (0.64 μg/ dl) than in fetal or maternal serum (9.3 and 11.3 μg/dl, respectively). Most of the T4 (99.4%) in AF is protein bound, presumably to TBG as in serum, but the mean FT4 concentration in AF at term (4.13 ng/dl) was significantly greater than the levels in fetal or maternal serum (2.67 or 2.56 ng/dl, respectively). The mean TBG level in AF at term was 0.26 mg/dl. T3 was not measurable in AF (<15 ng/dl). There were no significant correlations between the total or free T4 concentrations in maternal or fetal sera and in amniotic fluid. Thus AF thyroid hormone concentrations in the euthyroid fetus do not reliably reflect fetal serum T4 or T3 concentrations.
UR - http://www.scopus.com/inward/record.url?scp=0016817606&partnerID=8YFLogxK
U2 - 10.1016/S0022-3476(75)80636-6
DO - 10.1016/S0022-3476(75)80636-6
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AN - SCOPUS:0016817606
SN - 0022-3476
VL - 87
SP - 364
EP - 368
JO - Journal of Pediatrics
JF - Journal of Pediatrics
IS - 3
ER -