Leptin and Leptin Receptor Levels in Pregnant Women With Hyperemesis Gravidarum

Abstract

None of the many causes proposed for hyperemesis gravidarum have been established. Because serum levels of the peptide leptin increase rapidly in the first trimester of pregnancy and remain high throughout pregnancy, the investigators designed a prospective, controlled trial comparing concentrations of leptin, leptin receptor, and relevant hormones in 18 pregnant women with hyperemesis gravidarum and the same number of healthy pregnant women. Criteria for making this diagnosis included the inability to take oral nourishment in the first trimester, vomiting 4 or more times each day, and the presence of ketonuria. The 2 groups were similar in age, body mass index (BMI), and length of gestation. Women with hyperemesis had significantly higher leptin levels than their clinically normal counterparts, but there was no statistically significant difference in levels of leptin receptor. Leptin levels correlated significantly with BMI in the study group, but BMI did not relate significantly to leptin receptor levels in either group. No significant differences between groups were found in serum concentrations of human chorionic gonadotropin (hCG), cortisol, insulin, thyroid-stimulating hormone (TSH), free triiodothyronine, or free thyroxine. In women with hyperemesis gravidarum, there were inverse correlations between hCG and TSH, cortisol and leptin, insulin and leptin, and free triiodothyronine and hCG. These findings suggest that leptin may serve as a marker of hyperemesis gravidarum and also may play a role in its development.