The association between third trimester multivitamin/mineral supplements and gestational length in uncomplicated pregnancies

BackgroundWidespread use of maternal micronutrient supplements have been correlated to gestational length and outcome in women predisposed to pre-eclampsia and preterm birth. However, research is yet to be conducted examining the influence of micronutrient supplements on outcomes at term in uncomplicated pregnancies.AimTo analyse the relationship between third trimester micronutrient supplementation and gestation length at birth, demographics and maternal birthing outcomes in well women at term in a South East Queensland representative population.MethodsThis research retrospectively analysed existing data pertaining to 427 uncomplicated, pregnancies birthing at the Gold Coast and Logan Hospitals using information gathered through the Environments for Healthy Living Study and Queensland perinatal data collection. Data were analysed using SPSS v20 by Chi square, ANOVA and regression analysis.FindingsWomen in the third trimester taking individual zinc, folic acid or iron supplements in combination with a multivitamin were twice as likely to birth beyond 41 completed weeks (AOR 2.054, 95% CI 1.310–7.383, p = 0.038) then those who did not take any supplement when controlled for established confounders. Non supplement users were found to experience a lower rate of post dates labour and requirements for induction (AOR 0.483, 95% CI 0.278–0.840, p = 0.01).ConclusionLength of gestation demonstrates significant associations with micronutrient supplementation practices. Well women consuming third trimester individual micronutrient supplements in addition to multivitamins experienced a longer gestation at term compared to women taking no micronutrients, increasing their risk for postdates induction of labour.