Aims: The cause of striae gravidarum is still unclear. The study objective was to test the hypothesis that relaxin is involved in the process of striae gravidarum appearance during pregnancy.
Methods: A prospective observational study in 32 pregnant women. Participants were observed at 12th, 24th and 36th gestational week. During each session, striae scoring was assessed and blood for relaxin estimation was withdrawn. The striae assessment was done according to Davey score. Serum relaxin was estimated using Relaxin ELISA kit (Immunodiagnostic AG, Bensheim, Germany).
Results: Serum relaxin levels decreased as the pregnancy advanced (585.9 ± 295.1, 424.2 ± 253.8, 402.1 ± 221.2 pg/ml, respectively) but this decrease did not attain statistical significance. Pregnant women with striae gravidarum had lower serum relaxin levels compared to those without striae gravidarum at 36th gestational weeks, 330.8 ± 175.2 vs 493.8 ± 245.8 pg/ml (P = 0.037), respectively. The severity of striae gravidarum during pregnancy did not correlate with serum relaxin levels.
Conclusion: Lower serum relaxin levels could contribute to the occurrence of striae gravidarum during pregnancy through decreased elasticity of the connective tissue.