Menarche, sexual practices, and pregnancy: model testing.
Rates of adolescent pregnancy and childbearing, while in slight decline in the United States since 1992, remain high enough to warrant significant national concern. Birth rates, however, remain particularly high for minority adolescents. One hundred fifty-two records of African American and Latina adolescents receiving prenatal care from nurse midwives at an inner city university clinic were reviewed to partially test a developmental maturity model of pregnancy using logistic regression. The relationships between age at menarche to sexual practices and age at first pregnancy were examined. Mean age of the sample was 16.5 years, mean age at menarche was 12.2 years, at first coitus was 14.6 years, and at first pregnancy was 15.6 years. Thirty percent of the girls were experiencing second pregnancies. Birth control use by the adolescents was inconsistent, with only 20 percent using birth control at first coitus. Multiple regression analyses produced a model explaining 50 percent of the variance in age at first pregnancy. The predictor variables in the model were age at first coitus, age at menarche, race/ethnicity, and use of birth control at first coitus. Further analyses indicate that for childbearing adolescents, age at first coitus is a classic intervening variable between age at menarche and age at first pregnancy. Early physiologic maturers appear to lack the psychological and cognitive maturity required to cope with their emerging sexuality resulting in early unprotected coitus and pregnancy. Findings provide guidance to healthcare providers for the development of interventions to prevent unplanned pregnancies.