Trends in serum relaxin concentration among elite collegiate female athletes

Abstract

Purpose:This study was designed to investigate the relationship between serum relaxin concentration (SRC) and menstrual history and hormonal contraceptive use among elite collegiate female athletes. Evaluation of SRC in athletes is necessary, because relaxin has been associated with increased knee joint laxity and decreased anterior cruciate ligament (ACL) strength in animal models.Methods:National Collegiate Athletic Association Division I female athletes participating in sports at high risk for ACL tears – basketball, field hockey, gymnastics, lacrosse, soccer, and volleyball – were invited to participate. All participants completed a questionnaire about their menstrual history and hormonal contraceptive use. Venipuncture was performed to obtain samples of serum progesterone and relaxin. Samples were obtained during the mid-luteal phase from ovulating participants, and between the actual or projected cycle days 21 to 24, from anovulatory participants. Serum concentration of relaxin and progesterone was determined by ELISA and the data were analyzed using SPSS statistical software with significance set at P = 0.05.Results:169 female athletes participated. The mean SRC among all participants was 3.08 ± 6.66 pg/mL). The mean SRC differed significantly between those participants using hormonal contraceptives (1.41 pg/mL) and those not using hormonal contraceptives (3.08 pg/mL, P = 0.002). Mean SRC was lowest among amenorrheic participants (1.02 pg/mL) and highest among oligomenorrheic participants (3.71 pg/mL) and eumenorrheic participants (3.06 pg/mL); these differences were not significant (P = 0.53). Mean serum progesterone concentration (SPC) differed significantly between those participants using hormonal contraceptives (2.80 ng/mL), and those not using hormonal contraceptives (6.99 ng/mL, P < 0.0001).Conclusions:There is a positive correlation between serum progesterone and SRC and an attenuation of SRC with hormonal contraceptive use. Our results underscore the significant role that hormonal contraceptives can play in decreasing relaxin levels, if future investigations establish a link between relaxin levels and ligamentous injury among female athletes.

The Specificities of Elite Female Athletes: A Multidisciplinary Approach

“…In addition, women injure the knee anterior cruciate ligament (ACL) four to six times more often than men, which has prompted the suggestion that fluctuations in women’s endocrine environment might be a factor [ 78 ]. The presence of sex hormones or relaxing receptors in ACL might explain their effect on this structure, but other extrinsic or intrinsic factors may contribute to this process [ 79 , 80 ]. Recent reviews [ 81 , 82 ] seem to show a decreased risk of ACL injury during L vs. F and PeO, with increased ACL laxity in PeO at high E2 levels vs. other MC phases.…”

The effect of relaxin on the musculoskeletal system

“…Relaxin treatment in pregnant cattle increased pelvic width and height (Perezgrovas & Anderson, 1982 ; Musah et al., 1986 ), but not in other joints such as wrist and knee ( Weinberg, 1956 ; Marnach et al., 2003 ). Increase in serum relaxin concentration may also correlate with joint laxity ( Lubahn et al., 2006 ; Dragoo et al., 2011a , 2011b ), but this effect during pregnancy is controversial ( Forst et al., 1997 ). Some studies have reported higher relaxin levels in pregnant women with pelvic joint instability or hip joint laxity as compared with controls ( Saugstad, 1991 ; Steinetz et al., 2008 ), while other studies did not ( Ohtera et al., 2002 ).…”

Sex-Steroid Regulation of Relaxin Receptor Isoforms (RXFP1 & RXFP2) Expression in the Patella Tendon and Lateral Collateral Ligament of Female WKY Rats

“…While estrogen has been shown to affect ACL laxity in the animal model 43 , little is known with regards to the effect of progesterone and testosterone on knee ligament laxity. Dragoo et al, 57 measured serum relaxin concentration (SRC) in elite collegiate female athletes and had observed a positive correlation between SRC and serum progesterone concentration in athletes who are oligomenorrheic, eumenorrheic, not on oral contraceptive and have ovulatory cycle., In this study, serum progesterone level was measured to confirmed luteal phase measurement of relaxin as relaxin levels are known to be higher in this phase. Other studies involving female athletes have also indicated that knee laxity was increased during ovulation and in the luteal phase of the menstrual cycle 53 .…”