RESUMEN
Objectives: We evaluated the effect of multivitamin supplementation on delivery complications that can arise from maternal-fetal disproportion. Methods: We used data from a double-blind, randomized controlled trial among 8286 HIVnegative pregnant women in Dar es Salaam, Tanzania. From August 2001 to July 2004, eligible women were randomly assigned to receive daily multivitamins or placebo between 12 and 27 gestational weeks. All women received prenatal iron and folic acid supplementation. Results: Women in the multivitamin group experienced a 50% higher risk of prolonged labor requiring cesarean section or forceps delivery compared to the women in the placebo group (relative risk 1.52, 95% CI: 1.12-2.07; p=0.007). There was also a non-significant increase in the incidence of vaginal tear (RR-1.11 95% CI 0.99-1.24, p=0.06 ) in the multivitamin group. We found no difference in the risks of need for newborn resuscitation, low APGAR score and signs of fetal distress among the infants born to women receiving multivitamin and placebo. Increases in birth weight and head circumference of the newborn mediated 63% (95% CI- 33- 85%; P <0.0001) of the effect of the multivitamins on prolonged labor. In addition, maternal short stature (height <150 cm) and obesity (BMI≥30) were independently associated with significantly increased risks of prolonged labor. Conclusions: Multivitamin supplementation increased the risk of prolonged labor among HIVnegative pregnant women in Dar es Salaam. However, this risk did not result in any increased adverse fetal outcome. Routine multivitamin supplementation is best integrated in programs that provide emergency obstetric care for women at high risk for prolonged labor.