Age at menarche and pregnancy-related pelvic pain.

Aim: Menarcheal age is a predictor of several complications related to pregnancy and diseases later in life. We aimed to study if menarcheal age is a risk factor for pregnancy-related pelvic pain.

Material And Methods: A nested case-control study was conducted within the Danish National Birth Cohort, a cohort of pregnant women, recruited during 1996-2002, and their children. In the second trimester of pregnancy the women provided information about age at menarche and potential confounders. Selection of cases (n = 2227) was based on self-reported pelvic pain during pregnancy from an interview done 6 months post-partum. The controls (n = 2588) were randomly selected among women who did not report pelvic pain. We used logistic regression analysis to calculate odds ratios (OR) for pregnancy-related pelvic pain according to age at menarche.

Results: In the cohort, 18.5% of all pregnant women reported pregnancy-related pelvic pain. Compared to women who were 12-14 years old at menarche, the adjusted OR for overall pelvic pain were 1.4 (95% confidence interval [CI] 1.1-1.7) in women 11 years or younger and 0.8 (95%CI 0.6-0.9) in women 15 years or older. The corresponding adjusted OR for severe pelvic pain were 1.6 (95%CI 1.3-2.0) and 0.7 (95%CI 0.6-0.9). When age was analyzed as a continuous variable, the odds for overall and severe pelvic pain decreased with 14% and 16%, respectively, for each increasing year.

Conclusions: The risk of pregnancy-related pelvic pain decreased with increasing menarcheal age in an 'exposure-response' pattern. A low menarcheal age is a risk indicator and may be a risk factor for pregnancy-related pelvic pain.