# Menstrual cycle among adolescents: girls’ awareness and influence of age at menarche and overweight

## TL;DR

This study examines menstrual cycle patterns and disorders among adolescent girls in Lisbon, finding that early menarche is linked to more menstrual issues, but BMI is not.

## Contribution

The study identifies early menarche as a risk factor for menstrual disorders in adolescents, independent of BMI.

## Key findings

- 88% of girls experienced dysmenorrhea, with 49% using pain medication.
- Early menarche (<12 years) is associated with longer menstrual flow and higher dysmenorrhea risk.
- No significant link was found between BMI and menstrual cycle variables.

## Abstract

To characterize the menstrual cycle (regularity and menstrual flow length), the prevalence of dysmenorrhea and self-monitoring of the cycle in students from Lisbon region, and explore the effect of chronological age, age at menarche and body mass index (BMI) on menstrual disorders.

This is a cross-sectional study with 848 girls aged 12–18 years. A questionnaire about the sociodemographic context and characteristics of the menstrual cycle, and weight and height measures were assessed. BMI was classified according to International Obesity Taskforce criteria. A descriptive analysis of the variables was made, and Odds Ratios (ORs) and 95% confidence intervals (95%CIs) were determined.

Mean age at menarche was 12.4 years and mean BMI was 22.0kg/m2. Among adolescents, 59% have regular menstrual cycle, 83% have menstrual flow length of ≤6 days. 88% suffered from dysmenorrhea, among which 8,7% declare absenteeism from school and 49% took pain medication, and 65% self-monitor their menstrual cycle. Higher maternal education was associated with a higher self-monitoring of menstrual cycle among the sample (OR 1.60; 95%CI 1.15–2.17). Girls with menarche <12 years-of-age are more likely to have menstrual flow length of >6 days (OR 1.73; 95%CI 1.19–2.51) and dysmenorrhea (OR 1.87; 95%CI 1.11–3.16) than those with menarche ≥12 years-of-age. No significant association between BMI and menstrual cycle variables was observed.

The results suggest that menstrual disorders are frequent and may be associated with early menarche, but not with BMI. It is important to encourage self-monitoring of the menstrual cycle to detect menstrual disorders timely and promote health and well-being.