A rise in the number of pregnant adolescents in the last century is a cause of concern in public health (1), considering that lower maternal age has been associated with a higher prevalence of low birth-weight (LBW), maternal and neonatal morbidity and mortality. However, maternal age is not an independent determinant of intrauterine growth or gestational duration, but may indirectly influence nutrition and other important risk markers of LBW (2).
Pregnancy in adolescence means an increase in nutritional requirements for the growth of the foetus and for the mother herself and is a potential determinant of lower weight gain (3). However, the biological mechanism that underlies the relationship between women's nutritional status and reproductive outcomes is not fully understood, except in extreme situations (e.g. famine) (4).
In developing countries, many children with mild-to-moderate malnutrition survive to reach adolescence, when malnutrition tends to remain mild but chronic, being detectable only by anthropometric measurements. On the other hand, relatively well-nourished children may develop malnutrition in adolescence as a result of acquired dietary habits, influenced by obsession with thinness (5-9). Several studies, mainly from developed countries, have demonstrated that, despite the increasing trends in the prevalence of overweight and obesity, fatness phobia is common during female adolescence (10-14).
Brazil has been passing through a nutritional transition, with a dramatic shift towards obesity (15,16). Studies have shown a coexistence of malnutrition and obesity in low-income Brazilian communities (17), sometimes with these two conditions existing in the same household (18).
To examine only the nutritional aspects of pregnancy in adolescence is to take a limited approach, considering that the psychological consequences are of equal importance and may have an impact on the nutritional status of this population and on their babies (19). Adolescents are prepared neither physically nor emotionally for pregnancy. The World Health Organization considers adolescence to be the period between 10 and 20 years during which individuals undergo significant psychosexual and psychosocial development (5).
The relationship between the nutritional and the psychological status of pregnant adolescents also includes the possibility that it can be confounded by socioeconomic, demographic and obstetric factors. Stress/distress is likely to occur among adolescents who expect serious social disapproval when their condition becomes known. In this case, pregnancy is usually kept secret as long as possible, and antenatal care delayed. Even when these adolescents attend antenatal care services, a sense of shame, guilt, or inadequacy may grow, and further damage them, if they are not married. Usually, younger and poorer adolescents are the ones who are more in need of proper nutrition and psychological assistance (5). In addition, the relationship between their nutritional and psychological status may be influenced by unhealthy habits, such as smoking, alcohol or coffee consumption.
The objectives of this study were (1) to compare the toxic exposure and nutritional, psychological, socioeconomic, obstetric and demographic aspects of pregnant adolescents and non-adolescents and (2) to examine the association between the nutritional and the psychological status of pregnant adolescents and non-adolescents at the three interviews (gestational age [less than or equal to] 16 weeks, 20-26 weeks, and 30-36 weeks).
MATERIALS AND METHODS
This study is part of a large cohort study on risk factors for low birth-weight, prematurity and intrauterine growth retardation (19). It initially involved 1,182 pregnant women who attended for antenatal care during September 1997-August 2000 at 12 health centres and 5 hospitals in Jundiai, Southeast Brazil. The participants were insured by the "Sistema Unico de Saude"-SUS (the national health service that assists low-income families) and were interviewed at three different periods of pregnancy--at gestational age [less than or equal to] 16 weeks, 20-26 weeks, and 30-36 weeks. …