IS OVARIAN RELAXIN A STIMULUS TO PLACENTAL PROTEIN-14 SECRETION IN PREGNANCY

The objective of this study was to investigate whether relaxin might b e involved in placental protein 14 (PP14) secretion by measuring serum levels of PP14 during labour and post partum in normal women with a t erm pregnancy given vaginal human recombinant relaxin (rhR1x) gel for induction of labour. A randomized double-blind controlled trial was co nducted on 11 women with a singleton pregnancy at term admitted for in duction of labour. Comparison of serum PP14 and relaxin concentrations in the control and treated groups of subjects revealed that there was an increase in serum relaxin concentrations in women receiving 3 mg o r 6 mg relaxin. There was no difference in serum PP14 levels between t he control and treatment groups. These findings do not support the hyp othesis that relaxin is involved in the control of PP14 secretion. How ever, the failure of any response might be a consequence of the very s mall increase in systemic levels of relaxin produced by topical vagina l administration of rhR1x. Furthermore, these measurements were made i n late pregnancy and hence may not relate to the events in early pregn ancy, when serum levels of PP14 are maximal.