Controlled trial of zinc supplementation in Chilean pregnant adolescents

Objective. The aim of this study was to analyze the effect of zinc suppleme ntation on pregnancy outcome of Chilean adolescents from low socio-economic status (LSES); they often have low zinc intakes which may affect normal gr owth. Study design. A double blind randomised zinc supplementation trial wa s conducted with 804 healthy pregnant adolescents of LSES (age 16 +/- 1.3 y .). Individuals were randomly assigned to Zn supplemented (S, n = 401) or P lacebo (P, n = 403) groups. During the follow-up 297 were excluded. The S g roup received 20 mg Zn/d and the P group received a placebo, starting befor e 20 weeks of gestation. Results. On admission, both groups were comparable in age, rate of underweight, gestational age (12.5 vs 12.8 weeks), and die tary zinc intakes (7.3 vs 7.6 mg/d). At delivery, the S group presented a b irthweight of 3,319 +/- 460 g compared with 3,250 +/- 514 g in the P group (NS). The proportion of low birthweight (<2,500 g) in the S group was signi ficantly lower than in the P group (6/249 vs 16/258, p = 0.036). Prematurit y rate was lower in S than P (14/249 vs 30/258, p = 0.016). Multiple regres sions found a significant effect of maternal nutritional status (p = 0.011) and zinc supplementation (p = 0.05) on birthweight, No effects on pregnanc y complications, RBC or plasma alkaline phosphatase were found. Conclusions . Oral zinc supplementation affects favourably the pregnancy outcomes in Ch ilean adolescents from low socioeconomic status. (C) 2001 Elsevier Science Inc. All rights reserved.