morbidity-mortality.2 The LBW rate represented about
8% of all live births in Brazil in 2005,a as opposed to
a mean 4 to 5% rate of all live births in developed
countries.12
Higher percentages of LBW are observed in children
of adolescent mothers, as was the case in the city of
São Luís, Northeastern Brazil, 1997/98, with 13.2%
and 11.7% rates among mothers < 18 and 18 to 19
years old, respectively.21 The incidence of LBW
among adolescents is more than double that in adult
women, and neonatal mortality (zero to 28 days) is
approximately three times higher, increasing the risk
of morbidity-mortality during the fi rst year of life.2
According to Strobino et al,22 three different hypotheses
can be raised to explain higher LBW rates among children
of adolescent mothers in the United States: social disadvantage,
biological immaturity and unhealthy behavior
during pregnancy. However, after controlling for variables
directly related to unfavorable living conditions,
no differences in birth weight were observed between
adolescent mothers and mothers of other age ranges.