Are thyroid hormones or hCG responsible for hyperemesis gravidarum? A matched paired study in pregnant Chinese women.
OBJECTIVE
To determine the relative importance of thyroid hormones and human chorionic gonadotropin in the etiology of hyperemesis gravidarum.


METHODS
A prospective study comparing the hormonal status in women with hyperemesis gravidarum (5-18 weeks), with healthy pregnant controls, matched for gestational age. Sensitive thyroid stimulating hormone, free thyroxine, free triiodothyronine and total beta human chorionic gonadotropin were measured by immunoassays. The hormone results for hyperemesis gravidarum group (n=58) were compared with pregnant control women (n=58) using the Mann Whitney test. Stepwise logistic regression analysis was performed to determine which variables were significantly associated with hyperemesis gravidarum and to estimate the probability of each woman having hyperemesis gravidarum. The strength of the resulting association was tested by generating a receiver operating characteristic curve for predicting hyperemesis gravidarum using these probabilities.


RESULTS
Maternal age and all hormones were significantly different between the hyperemetic and control groups. However, logistic regression analysis demonstrated that only maternal age, free thyroxine and thyroid stimulating hormone were significant independent variables. The area beneath the receiver operating characteristic curve for prediction of hyperemesis gravidarum was 0.84.


CONCLUSIONS
Human chorionic gonadotropin is not independently involved in the etiology of hyperemesis gravidarum but may be indirectly involved by its ability to stimulate the thyroid. Differences in maternal age and thyroid function are highly discriminatory with regard to hyperemesis gravidarum.
Panesar
N S
NS
Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
Li
C Y
CY
Rogers
M S
MS
D000328:Adult; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D006063:Chorionic Gonadotropin / Q000032:analysis*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006939:Hyperemesis Gravidarum / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology*; D016015:Logistic Models; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011336:Probability; D011446:Prospective Studies; D012372:ROC Curve; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013963:Thyroid Hormones / Q000032:analysis*
D006063:Chorionic Gonadotropin; D013963:Thyroid Hormones