Objective: The relationship between intrauterine growth retardation and sexual maturation has not been completely established. The aim of the present study was to compare menarche in 14-year-old Polish girls of low and normal birthweight, along with an evaluation of the impact of socio-economic status and body mass index (BMI).
Methods: We studied 1060 girls (177 pre- and 883 post-menarche) aged 13.5−14.5 years. These girls attended the 7th grade of randomly selected primary schools in Wroclaw, Poland. The BMI was used as a measurement of general adiposity. The cut-off value of the 10th percentile of birthweight for gestational age was used to differentiate between girls born small for gestational age (SGA) and girls with a birthweight appropriate to gestational age (AGA). Parental education level and other measures were used to assess socio-economic status (SES).
Results: Birthweight (OR = 2.54; 95% CI 1.22−5.28) and BMI at the age of 14 years (OR = 7.93; 95%CI 4.67−13.48) were factors affecting the onset of menarche among the 14-year-old girls.
Conclusion: Polish girls born small for gestational age are more likely to have experienced menarche by the age of 14 years, compared with their peers of normal weight at birth. These findings seem to be consistent with the hypothesis that the age of menarche is, to some extent, set by patterns of gonadotropin release, established prior to birth. Additionally, the age of menarche varies depending on levels of fat accumulation during childhood and adolescence.