Endocrine Abstracts

Introduction: Normal thyroid function is necessary for normal body function. During pregnancy if the thyroid hormone deficiency, it will induce maternal and fetal hypothyroxinemia. And the vulnerable fetuses and neonates will suffer from irreversible deficit in the neuro-psycointellectual development including mental retardation. It is being established that albumin level decreases during pregnancy with recorded increase in urine microalbumin, An elevation in both thyroid stimulating hormone (TSH) and TBG levels was also described during pregnancy.

Therefore, the aim of this study was to investigate the relation between TSH and TBG changes and its correlation to reduced albumin during the three trimesters of pregnancy.

Method: Blood samples were collected from 20 healthy nonpregnant (control) and pregnant females at their first (n=32), second (n=29) and third trimesters (n=30). Serum albumin, thyroid stimulating hormone (TSH) and thyroid binding globulin (TBG) were measured as well as urine microalbumin.

Results: Albumin levels were a significantly reduced P<0.01, by the third trimester compared to control subjects. A small increase in urine microalbumin was noted with progression of pregnancy, however, not significant. Measurements of TBG and TSH showed a statistically significant increase in both parameters with the progression of pregnancy, and the changes in TBG levels were negatively correlated (r=−.08) with a similar percent of change noticed in albumin levels. This was manifested by the 43%, 52% and 56% increase in the TBG levels in the first, second and third trimesters compared to control respectively.

Conclusion: The albumin reduction during pregnancy is known to be resulting from the increased glomerular filtration rate. Albumin is also known as a minor carrier protein for thyroid hormones, therefore, we propose increased TBG levels is a response and compensatory to the reduction in albumin to meet the high demand for the fetus for the thyroid hormones.