Endocrine Abstracts

Background: The pregnancy-specific condition pre-eclampsia (PE) affects ~2% of women contributing to neonatal and maternal morbidity and has been linked with a deficiency in selenium. The iodothyronine deiodinases all contain selenium and play crucial roles in determining the circulating and intracellular levels of the active thyroid hormone. It is hypothesised that due to the role of deiodinases in extrathyroidal production of T3, thyroid-stimulating hormone (TSH) will be increased in PE to preserve free T3 (FT3) and T4 (FT4).

Objectives: To measure maternal and umbilical venous (UV) serum (TSH), (FT4) and (FT3) in Caucasian women with PE, normotensive controls (NC) and non-pregnant controls (NPC).

Design: Following ethical approval and informed consent, a single venous blood sample was taken at delivery from 22 NPC women, 24 PE and 26 NC women; UV samples were also obtained where possible. PE was defined as blood pressure of ≥140/90 mmHg in a previously normotensive woman, combined with proteinuria of ≥300 mg/l after 20 weeks gestation. (TSH), (FT4) and (FT3) were measured by immunoassays using the ADVIA Centaur system in the Clinical Chemistry laboratories, QMC, to whom we express our thanks.

Results: Conclusion: The raised UV (TSH) in PE may reflect an adaptive response by the fetus to increase (TSH) thus maximising iodide uptake thereby maintaining normal (FT4) and (FT3). The raised (TSH) may be a consequence of increased hypoxia placed on these babies due to inadequate placentation and possibly compensate for the selenium deficiency.