The Association of Reproductive Hormones During the Menstrual Period with Primary Dysmenorrhea

OBJECTIVE: This study aimed to investigate the association of reproductive hormones with primary dysmenorrhea in Chinese women. METHODS: A case–control study was conducted and patients with primary dysmenorrhea and non-dysmenorrhea participants were recruited. Oxytocin, PGF(2α), vasopressin, estriol and estradiol were respectively measured in plasma collected three to five days after menstruation. Restricted cubic spline and multiple logistic regression models were adopted to analyze the association between hormones and primary dysmenorrhea. RESULTS: There were 604 participants enrolled in our study including 300 patients with primary dysmenorrhea. After adjustment for the potential confounders, oxytocin levels (Q(3): OR (95% CI) = 0.50 (0.27~0.95) (p=0.035); Q(4): 0.34 (0.17~0.66) (p=0.001)) and PGF(2α) levels (Q(3): 0.45 (0.24~0.87) (p=0.017); Q(4): 0.43 (0.22~0.84) (p=0.013)) were respectively associated with an decreased risk of primary dysmenorrhea, but estradiol (Q(2): 2.18 (1.13~4.19) (p=0.020); Q(3): 2.17 (1.12~4.19) (p=0.022)) and vasopressin (Q(3): 2.88 (1.48~5.63) (p=0.002); Q(4): 3.20 (1.65~6.22) (p<0.001)) with an increased risk of primary dysmenorrhea, respectively. Among patients with primary dysmenorrhea, the higher estriol level was associated with higher frequent dysmenorrhea (Q(2): 3.12 (1.32~7.34) (p=0.009); Q(3): 4.97 (2.08~11.85) (p<0.001)) and always dysmenorrhea (Q(2): 2.51 (1.03~6.11) (p=0.041); Q(3): 3.10 (1.25~7.73) (p=0.015)). Similarly, high estriol levels were associated with the higher degree of pain significantly only when hormone levels were at a high level (Q3: 2.06 (1.03~4.18) (p=0.043)). CONCLUSION: Higher serum vasopressin and estradiol concentrations as well as lower oxytocin and PGF(2α) levels were associated with higher risk of primary dysmenorrhea. Estrogen showed a reverse U-shape association on the frequency and degree of pain among patients with primary dysmenorrhea.