Human chorionic gonadotropin and relaxin concentrations in early ectopic and normal pregnancies

The present study was performed to investigate whether determination of serum relaxin concentrations would allow assessment of the gestation further than that provided by determination of hCG. Serum relaxin concentrations were quantified in women with resorbing ectopic gestations (as documented by declining titers of beta-hCG). The control group consisted of individuals with intrauterine pregnancies. As an additional control, we studied pregnancies conceived through ovulation induction, which usually have an increased volume of relaxin-secreting luteal tissue. On days 39-70 of gestation, the mean serum relaxin concentrations were significantly lower in ten resorbing ectopic gestations (P less than .001, permutation test) than in the normal control group of 13 intrauterine pregnancies. The median serum relaxin concentrations in patients who had ovulation induction with Pergonal were substantially higher than the median for all normal controls; values in clomiphene citrate-treated patients were within the normal range. These data suggest that relaxin secretion correlates with luteal function in both normal and abnormal gestations and reflects the status of the pregnancy. Thus, relaxin may serve as a useful clinical marker.