Predictive value of menstrual cycle pattern, body mass index, hormone levels and polycystic ovaries at age 15 years for oligo-amenorrhoea at age 18 years.

BACKGROUND: On the question of how to counsel adolescents with irregular menstrual cycles or oligomenorrhoea, no clear answer has been given. Adolescents with oligomenorrhoea especially show endocrine abnormalities and may be at risk for ovulatory dysfunction and the polycystic ovary syndrome in adulthood.
METHODS: We followed a cohort of adolescents to document changes in menstrual cycle pattern between ages 15 and 18 years in the general population.
RESULTS: Two per cent (2/128) of adolescents with regular menstrual cycles developed oligomenorrhoea, and 12% (17/148) of those with irregular menstrual cycles did so. Fifty-one per cent (34/67) of the oligomenorrhoeic adolescents remained oligomenorrhoeic. Increase in body mass index (BMI), concentration of LH, androstenedione or testosterone, and polycystic ovaries (PCO) were associated with persistence of oligomenorrhoea. In multivariate analysis only a normal to high BMI (>19.6 kg/m(2)) consistently contributed significantly to predict persistent oligomenorrhoea. Glucose:insulin ratio as a marker for insulin resistance was not associated with an increased risk for oligomenorrhoea.
CONCLUSIONS: Oligomenorrhoea at age 18 years is better predicted by menstrual cycle pattern at age 15 years than by LH or androgen concentrations or PCO at this age. Not only obese, but also normal weight oligomenorrhoeic, adolescents have a high risk of remaining oligomenorrhoeic.