Maternal-to-fetal transfer of thyrotropin-releasing hormone in vivo

Bajoria, Rekha, Peek, Michael J. and Fisk, Nicholas M. (1998) Maternal-to-fetal transfer of thyrotropin-releasing hormone in vivo. American Journal of Obstetrics and Gynecology, 178 2: 264-269. doi:10.1016/S0002-9378(98)80011-2

Author Bajoria, Rekha
Peek, Michael J.
Fisk, Nicholas M.
Title Maternal-to-fetal transfer of thyrotropin-releasing hormone in vivo
Journal name American Journal of Obstetrics and Gynecology   Check publisher's open access policy
ISSN 0002-9378
Publication date 1998-02
Sub-type Article (original research)
DOI 10.1016/S0002-9378(98)80011-2
Volume 178
Issue 2
Start page 264
End page 269
Total pages 6
Place of publication Philadelphia, PA, United States
Publisher Mosby
Language eng
Formatted abstract
Our purpose was to determine the transplacental transfer of thyrotropin-releasing hormone at the time of fetal blood sampling.


Four hundred micrograms of thyrotropin-releasing hormone was given intravenously to 13 pregnant women between 24 and 35 weeks' gestation and maternal-to-fetal transfer of thyrotropin-releasing hormone was determined at fetal blood sampling 1 to 93 minutes later. The fetal thyrotropic response to thyrotropin-releasing hormone was determined by measuring thyroid-stimulating hormone, thyroxine, and prolactin. For comparison, endogenous fetal and maternal levels of thyrotropin-releasing hormone, thyroid-stimulating hormone, thyroxine, and prolactin levels were determined in a further 20 patients undergoing fetal blood sampling between 19 and 35 weeks' gestation. The concentration of thyrotrophin-releasing hormone was measured by radioimmunoassay and thyroid-stimulating hormone, thyroxine, and prolactin by chemiluminescence assay.


Thyrotropin-releasing hormone was undetectable in the maternal circulation, whereas endogenous levels were detectable in the fetus from 19 weeks' gestation (median 150; range 50 to 276 pmol/L) and did not correlate with gestational age. After thyrotropin- releasing hormone injection as an intravenous bolus, peak levels in the mother were attained at 3 minutes (50,000 pmol/L). Maximal transplacental transfer of thyrotropin-releasing hormone occurred within 5 minutes of maternal administration but accounted in fetal blood for only 0.01% of initial) dose administered (median 250; 30 to 550 pmol/L). Thyrotropin- releasing hormone-stimulated fetal peak thyroid-stimulating hormone levels occurred within 13 minutes and were higher then maternal values (p < 0.001). There was no change in fetal prolactin level with thyrotropin-releasing hormone therapy.

Although maternally administered thyrotropin- releasing hormone crosses the placenta sparingly, it still elicits a thyroid- stimulating hormone but not a prolactin response in the human fetus.
Keyword Thyrotropin-releasing hormone
Placental transfer
Respiratory distress syndrome
Preterm labor
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Faculty of Health and Behavioural Sciences -- Publications
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