Irregular menstruation and hyperandrogenaemia in adolescence are associated with polycystic ovary syndrome and infertility in later life: Northern Finland Birth Cohort 1986 study

study question: Do teenage girls with a history of menstrual irregularity and/or elevated androgen levels in adolescence exhibit an increased risk of polycystic ovary syndrome (PCOS) and/or infertility later on in adulthood? summary answer: Our results suggest that menstrual irregularity and/or elevated androgen levels at 16 years are still associated with symptoms of PCOS at 26 years as well as infertility problems at 26 years but not with decreased pregnancy or delivery rates at 26 years. what is known already: Hyperandrogenaemia is associated with menstrual irregularity, hirsutism, acne and potentially higher risk for PCOS, but there are fewfollow- up studies investigating whether adolescent hyperandrogenaemia and/or menstrual irregularity are an early sign of PCOS. study design, size, duration: A prospective population-based cohort study was conducted using two postal questionnaires targeting girls in the Northern Finland BirthCohort 1986 (NFBC1986, n = 4567). The NFBC1986 comprises all expected births from the year 1986 in the two northernmost provinces of Finland. Collection of the database was performed at the age of 16 and 26. The 16-year and 26-year questionnaires included one question about the regularity and length of the menstrual cycle. The 26-year questionnaire also included questions about symptoms of PCOS, reproduction and infertility problems. participants, setting, methods: The response rates for the questionnaires were 80% (n = 3669) at 16 years and50% (n = 2270) at 26 years. At 15-16 years, of 2448 girls, 709 (29%) girls reported menstrual irregularity ( symptomatic girls) and 1739 ( 71%) had regular periods (non-symptomatic girls). After combining data fromthe two questionnaires a total of 2033 girlswere included in the analyses. Thex 2 and Student's t-test was used to compare reproductive outcome and prevalence of clinical hyperandrogenaemia, PCOS and infertility at 26 years between the study groups. Univariate and multivariate logistic regression models were employed to estimate the association of menstrual irregularity at 16 years with clinical hyperandrogenaemia, PCOS and infertility at 26 years. main results and the role of chance: At follow-up, the proportion of symptomatic girlswho had conceived at least once (68.0 versus 67.9%) and had delivered at least one child ( 25.7 versus 28.1%) was similar to the non-symptomatic women and the groups had similarmiscarriagerates (11.6versus12.1%). Logistic regressionanalyses indicatedthatmenstrual irregularityat16yearswas associatedwithanincreasedriskof