Investigating maternal serum thyroid hormone,beta-human chorionic gonadotropin (beta-HCG) and free beta-HCG levels in hyperemesis gravidarum

Objective: To investigate the influence of thyroid hormones,beta human chorionic gonadotropin (β-HCG),and free β-HCG (fβ-HCG) in the etiology of hyperemesis gravidarum (HG) and to determine the main hormone that is responsible for the exacerbation of symptoms. Materials and Methods: Serum thyroid-stimulating hormone (TSH),free triiodothyronine (fT3),free thyroxine (fT4),β-HCG,and fβ-HCG levels were measured twice (before and after hospitalization) in 55 patients with HG and measured once in 64 healthy controls. Serum hormone levels were determined using enzyme-linked immunosorbent assay. Results: Decreased mean TSH and increased mean fT4 levels were found in the pre-treatment serum samples of the HG group compared with the control group. Both differences were statistically significant (p=0.020 and p=0.007,respectively). However,there was no statistically significant difference in mean fT3,β-HCG,and fβ-HCG levels between the pre-treatment serum samples of the HG group and control group. We could not demonstrate any correlation between the levels of β-HCG and thyroid hormones in the HG group; however,fβ-HCG moderately correlated with fT4 levels (r=0.494). Conclusion: The presence of hyperthyroidism was observed as the leading alteration in HG. In this study,fβ-HCG was demonstrated to have no direct effect on the etiology of HG; however,a possible indirect effect of fβ-HCG in relation with thyroid hormones was indicated. Hyperthyroidism was assessed to be primarily responsible for the symptoms in HG.