CIRCULATING LEVELS OF RELAXIN ARE NORMAL IN PREGNANT-WOMEN WITH PELVIC PAIN

Objective: The hormone relaxin induces loosening of the pelvic ligamen ts and joints in several species. Previous studies have suggested a si milar role for relaxin during human pregnancy. Furthermore, a correlat ion has been noted between high circulating levels of this hormone and severe pelvic pain in pregnant women. The present study was designed to evaluate whether serum relaxin concentrations were elevated in preg nant women with clear subjective and objective evidence of pain attrib utable to relaxation of the pelvic ligaments. Study design: Serum rela xin was measured at week 33 of gestation in 455 pregnant women with cl early defined pain in their pelvic joints and 455 normal pregnant cont rols matched for age and parity. All participants underwent an examina tion consisting of a structured questionnaire and fifteen specific tes ts for pelvic joint pain. The group with pain was further subdivided i nto four subgroups with different levels of disability and prognosis. Relaxin concentrations were measured using enzyme-linked immunoassay. Results: There was no difference in serum relaxin concentration betwee n the control and study group, nor between the subgroups of women with pelvic pain. Conclusion: We failed to confirm an earlier claim that c irculating relaxin levels are related to pelvic girdle pain in pregnan t women. (C) 1997 Elsevier Science Ireland Ltd.