Deardorff J, Gonzales NA, Christopher FS, Roosa MW, Millsap RE. Pediatrics. 2005 Dec;116(6):1451-6.

OBJECTIVE: Early pubertal timing predicts deleterious outcomes for young girls, including substance use, risky sexual behavior, and pregnancy. In turn, adolescent pregnancy predicts long-term negative consequences such as reduced educational attainment and income-earning potential. Despite evidence of the direct links between early puberty and negative outcomes, this study is the first to examine the role that alcohol plays in the timing of sexual intercourse and pregnancy among early-maturing females.

DESIGN: Participants were 666 females, aged 18 to 22 years, from 4 major ethnic groups in Arizona (non-Hispanic white, black, Latino, and Native American). All women included in the sample had experienced a pregnancy in their teens or early 20s. Participants completed a self-administered questionnaire that inquired about their timing of menarche, sexual initiation, first alcohol use, and age at first pregnancy. A mediating model predicting age at pregnancy was tested by using path modeling.

RESULTS: Early puberty was found to be associated with earlier age of alcohol use and sexual initiation, which in turn predicted early pregnancy. Age at first sexual intercourse and age at first substance use significantly mediated the relation between age at menarche and age at first pregnancy. The results did not vary by ethnic group.

CONCLUSIONS: Girls who mature early are more likely to engage in early substance use and sexual intercourse, which in turn puts them at greater risk for adolescent pregnancy. It is important that health care providers are sensitive to the risks associated with early maturation among young girls and provide preventive screening, education, and counseling related to alcohol use and sexual initiation for this group.