Differing effects of low and high bulk maternal dietary supplements during pregnancy. Zinc supplementation during pregnancy in low-income teenagers of Mexican descent: effects on selected blood constituents and on progress and outcome of pregnancy. Zinc supplementation during pregnancy: a double blind randomised controlled trial. Zinc supplementation during pregnancy: a double blind randomised controlled trial. Zinc supplementation during pregnancy: effects on selected blood constituents and on progress and outcome of pregnancy in low-income women of Mexican descent. Effects of alternative maternal micronutrient supplements on low birth weight in rural Nepal: double blind randomised community trial. Effects of zinc supplementation during pregnancy on pregnancy outcome in women with history of preterm delivery: a double-blind randomized, placebo-controlled trial. Adding zinc to prenatal iron and folate supplements improves maternal and neonatal zinc status in a Peruvian population. Oral zinc supplementation in pregnant women and its effect on birth weight: a randomised controlled trial. A randomized, placebo-controlled trial of the effect of zinc supplementation during pregnancy on pregnancy outcome in Bangladeshi urban poor. Zinc supplementation during pregnancy. Randomized controlled trial of prenatal zinc supplementation and the development of fetal heart rate. Adolescent pregnancy: associations among body weight, zinc nutriture, and pregnancy outcome. Effect of prenatal zinc supplementation on birthweight.
The study attempted to determine if the bulk of dietary supplements given to pregnant women after midgestation affects fetal growth. 127 Zulu women were randomly assigned to four groups, two of which received daily food supplements designed to raise their energy, protein and vitamin intakes to levels recommended by the U.S. Food and Nutrition Board. One of these supplements had a high bulk, the other a low bulk. The third supplement contained only zinc and the fourth a placebo. Women in all four groups had a similar weight gain and length of gestation. Birth weights were from 6.5 to 9.5% greater with the low bulk than with the other supplements. As a follow-up of our study of pregnant women, we report effects of zinc supplementation during pregnancy in another population of 138 Hispanic teenagers in Los Angeles. Teenagers were randomized (double-blind) to a control or zinc-supplemented group and received similar daily vitamin and mineral supplements except for 20 mg zinc added to the zinc-supplemented group's capsules. Initially, mean dietary zinc intakes of both groups were about 50% of the Recommended Dietary Allowance and their mean serum zinc levels did not differ significantly (69.8 +/- 11.2 micrograms/dl in control and 69.0 +/- 11.4 micrograms/dl in zinc-supplemented group). Zinc supplementation did not maintain mean serum zinc levels during pregnancy but, as in our earlier study, it reduced (p = 0.018) the number of low serum zinc values (less than or equal to 53 micrograms/dl) in late pregnancy. Zinc supplementation did not affect outcome of pregnancy but serum zinc levels were lower (p = 0.038) in teenagers with pregnancy-induced hypertension than in normotensives. To investigate whether zinc supplementation during pregnancy improves maternal and fetal outcome.
                Controlled clinical trial started at registration until discharge of mother and child from hospital. Two thousand volunteer mothers were randomly assigned to receive zinc supplementation or placebo in a double blind trial.
                Women less than 20 weeks pregnant at the first visit who agreed to take part in the study. One thousand two hundred and six mothers were available for study.
                Volunteers were randomly selected to receive two tablets of zinc (44 mg zinc in total) or two placebo tablets containing inert substances, indistinguishable in appearance and taste from the zinc tablets.
                Large for gestational age (LGA), small for gestational age (SGA), premature rupture of the membrane (PROM), preterm labor (PL), preeclampsia and bleeding in the second or third trimester.
                There were no differences between mothers given zinc supplementation concerning the outcome parameters and those given placebo.
                Zinc supplementation in pregnancy in a normal healthy middle class population in Denmark does not seem to offer any benefits to the mother or her fetus. To see whether zinc supplementation during pregnancy improves maternal and fetal outcome.
                Prospective study started at booking and continued till discharge of mother and baby from the maternity hospital. Mothers were randomly assigned to receive zinc supplementation or placebo in a double blind trial.
                Mothers booking at one hospital.
                Women booking before 20 weeks of gestation who agreed to take part in the study. 494 Mothers were followed up till the end of pregnancy. There was no difference between the groups given zinc and placebo in their social or medical backgrounds.
                Mothers in the active treatment group received one capsule of 20 mg elemental zinc daily and those in the placebo treated group a capsule identical in appearance and taste with the active capsule but which contained inert substances.
                Various adverse outcomes were tested, including maternal bleeding, hypertension, complications of labour and delivery, gestational age, Apgar scores, and neonatal abnormalities. The main outcome measure was birth weight.
                There were no differences whatsoever between mothers given a zinc supplement and those given a placebo.
                Zinc supplementation in pregnancy in the United Kingdom does not seem to offer any benefits to the mother or her fetus. The effects of zinc supplementation on levels of various blood constituents and the outcome of pregnancy in 213 Hispanic women attending a prenatal clinic in Los Angeles was assessed in this double-blind study. The women were randomized into either a control (C) or a zinc-supplemented (Z) group and received similar vitamin and mineral supplements except that 20 mg zinc was added to the Z group's capsules. At the final interview, women (C + Z) with low serum Zn levels (less than or equal to 53 micrograms/dl) had higher (p less than 0.01) mean ribonuclease activity and lower (p less than 0.01) mean delta-aminolevulinic acid dehydratase activity than women with acceptable serum zinc levels. The incidence of pregnancy-induced hypertension was higher (p less than 0.003) in the C than in the Z group, but pregnancy-induced hypertension was not associated with low serum zinc levels at either the initial or final interview. The expected increase in serum copper levels was greater (less than 0.001) in women with pregnancy-induced hypertension (C + Z) than in normotensives. Except for pregnancy-induced hypertension, there was a higher incidence of abnormal outcomes of pregnancy in the noncompliers than in the compliers (C + Z). To assess the impact on birth size and risk of low birth weight of alternative combinations of micronutrients given to pregnant women.
                Double blind cluster randomised controlled trial.
                Rural community in south eastern Nepal.
                4926 pregnant women and 4130 live born infants.
                426 communities were randomised to five regimens in which pregnant women received daily supplements of folic acid, folic acid-iron, folic acid-iron-zinc, or multiple micronutrients all given with vitamin A, or vitamin A alone (control).
                Birth weight, length, and head and chest circumference assessed within 72 hours of birth. Low birth weight was defined <2500 g.
                Supplementation with maternal folic acid alone had no effect on birth size. Folic acid-iron increased mean birth weight by 37 g (95% confidence interval -16 g to 90 g) and reduced the percentage of low birthweight babies (<2500 g) from 43% to 34% (16%; relative risk=0.84, 0.72 to 0.99). Folic acid-iron-zinc had no effect on birth size compared with controls. Multiple micronutrient supplementation increased birth weight by 64 g (12 g to 115 g) and reduced the percentage of low birthweight babies by 14% (0.86, 0.74 to 0.99). None of the supplement combinations reduced the incidence of preterm births. Folic acid-iron and multiple micronutrients increased head and chest circumference of babies, but not length.
                Antenatal folic acid-iron supplements modestly reduce the risk of low birth weight. Multiple micronutrients confer no additional benefit over folic acid-iron in reducing this risk. The aim of this study was to assess the effect of high dose zinc (Zn) supplement during pregnancy in pregnancy outcome in healthy pregnant women with a previous preterm delivery in Isfahan, Iran.
                A double-blind placebo-controlled randomized clinical trial was conducted between January 2007 and June 2008. Eighty-four pregnant women with a previous preterm delivery age 19 to 35 years were randomly allocated to receive either 50 mg/day Zn as Zn sulfate or placebo from 12 to 16 weeks of gestation till delivery. Pregnancy outcome was assessed in term of incidence of intrauterine growth retardation (IUGR), birth weight, crown-heel length, head circumference, Apgar score, and gestational age at delivery.
                The mean birth head circumference was higher in Zn supplemented group than in the placebo group (35.0 cm vs. 33.7 cm, P < 0.05). Although gestational age at delivery (37.1 week vs. 36.7 week) and birth weight (2960.6 g vs. 2819.0 g) of babies born in Zn supplemented group was slightly higher than placebo group, it was not statistically significant. No significant differences were seen for infant length, Apgar score, and IUGR.
                Adding Zn supplementation during pregnancy to routine care of women with a previous preterm delivery had no significant effect on the gestational age at delivery and birth weight but increased the birth head circumference. Maternal zinc deficiency during pregnancy may be widespread among women in developing countries, but few data are available on whether prenatal zinc supplementation improves maternal and neonatal zinc status.
                We studied whether maternal zinc supplementation improved the zinc status of mothers and neonates participating in a supplementation trial in a shantytown in Lima, Peru.
                Beginning at gestation week 10-24, 1295 mothers were randomly assigned to receive prenatal supplements containing 60 mg Fe and 250 microg folate, with or without 15 mg Zn. Venous blood and urine samples were collected at enrollment, at gestation week 28-30, and at gestation week 37-38. At birth, a sample of cord vein blood was collected. We measured serum zinc concentrations in 538 women, urinary zinc concentrations in 521 women, and cord zinc concentrations in 252 neonates.
                At 28-30 and 37-38 wk, mothers receiving zinc supplements had higher serum zinc concentrations than mothers who did not receive zinc (8.8 +/- 1.9 compared with 8.4 +/- 1.5 micromol/L and 8.6 +/- 1.5 compared with 8.3 +/- 1.4 micromol/L, respectively). Urinary zinc concentrations were also higher in mothers who received supplemental zinc (P < 0.05). After adjustment for covariates and confounding factors, neonates of mothers receiving zinc supplements had higher cord zinc concentrations than neonates of mothers who did not receive zinc (12.7 +/- 2.3 compared with 12.1 +/- 2.1 micromol/L). Despite supplementation, maternal and neonatal zinc concentrations remained lower than values reported for well-nourished populations.
                Adding zinc to prenatal iron and folate tablets improved maternal and neonatal zinc status, but higher doses of zinc are likely needed to further improve maternal and neonatal zinc status in this population. Pakistan lies in a zinc deficient area where oral zinc supplementation has been advocated for various reasons. A double blind, randomised case-control study was carried out on pregnant women to evaluate the effects of oral zinc supplementation on the weights of newborns. No significant difference was found in the birth weights between the cases supplemented with 20 mg elemental zinc and controls receiving oral placebos (p=0.57). Maternal zinc supplementation has been suggested as a potential intervention to reduce the incidence of low birth weight in developing countries. To date, placebo-controlled trials have all been performed in industrialized countries and the results are inconsistent.
                The objective of this study was to evaluate whether zinc supplementation in Bangladeshi urban poor during the last 2 trimesters of pregnancy was associated with pregnancy outcome.
                We conducted a double-blind, placebo-controlled trial in which 559 women from Dhaka slums, stratified by parity between 12 and 16 wk of gestation, were randomly assigned to receive 30 mg elemental Zn/d (n = 269) or placebo (n = 290). Supplementation continued until delivery. Serum zinc was estimated at baseline and at 7 mo of gestation. Dietary intake was assessed at baseline and anthropometric measurements were made monthly. Weight, length, and gestational ages of 410 singleton newborns were measured within 72 h of birth.
                At 7 mo of gestation, serum zinc concentrations tended to be higher in the zinc-supplemented group than in the placebo group (15.9 +/- 4.4 compared with 15.2 +/- 4.3 micromol/L). No significant effect of treatment was observed on infant birth weight (2513 +/- 390 compared with 2554 +/- 393 g; NS) or on gestational age, infant length, or head, chest, or midupper arm circumference. The incidence and distribution of low birth weight, prematurity, and smallness for gestational age also did not differ significantly after zinc supplementation.
                Supplementation with 30 mg elemental Zn during the last 2 trimesters of pregnancy did not improve birth outcome in Bangladeshi urban poor. These results indicate that interventions with zinc supplementation alone are unlikely to reduce the incidence of low birth weight in Bangladesh. nan This study was undertaken to evaluate whether prenatal zinc supplementation affects maturation of fetal cardiac patterns.
                A randomized double-blind controlled trial among 242 low-income Peruvian women was performed. Beginning at 10 to 16 weeks' gestation, women received supplements containing 60 mg iron, 250 microg folic acid with or without 25 mg zinc. Fetal heart rate (mean FHR, variability [HRV], number of accelerations) and movements (number and amplitude of movement bouts, time spent moving) were electronically monitored monthly from 20 weeks' gestation. Developmental trends were evaluated by supplement type among 195 women who completed the trial and had no serious complications of pregnancy.
                Zinc supplementation was associated with lower FHR, greater number of accelerations, and greater HRV. Supplementation effects on HRV and accelerations were more pronounced after 28 weeks' gestation. No differences in motor activity were observed.
                Prenatal supplementation of zinc-deficient mothers may be beneficial to fetal neurobehavioral development. In a double-blind zinc trial in low-income, pregnant adolescents thought to be at risk for poor zinc nutriture, subjects were randomly assigned to receive 30 mg zinc (gluconate) or placebo. Response to zinc was related to maternal weight. Infants of normal-weight mothers given zinc had reduced rates of prematurity (p = 0.05) and assisted respiration (p = 0.006). Underweight multiparas given zinc had longer gestational lengths (p = 0.008) than did subjects given the placebo. Multiple stepwise regression analysis, used to identify predictors of infant size, revealed that 14-26% more variance was accounted for in the zinc than in the placebo group. Except for gestational age, the predictors selected were entirely different in the two groups. The zinc group had a positive toxemia screen more often, which did not appear to affect outcome. Zinc supplementation improved pregnancy outcome in normal-weight women and in underweight multiparas. The nonresponse in underweight primiparas was perhaps due to multiple limiting factors. Although iron and zinc deficiencies are known to occur together and also appear to be high in Ghana, a few supplementation studies addressed this concurrently in pregnancy. In a double-blind, randomized controlled trial, 600 pregnant women in Ghana were randomly assigned to receive either a combined supplement of 40 mg of zinc as zinc gluconate and 40 mg of iron as ferrous sulphate or 40 mg of elemental iron as ferrous sulphate. Overall, there was no detectable difference in the mean birthweight between the study groups, although the effect of iron-zinc supplementation on the mean birthweight was masked by a strong interaction between the type of supplement and the iron status of participants [F (1,179) = 5.614, p = 0.019]. Prenatal iron-zinc supplementation was effective in increasing the mean birthweight among anaemic and iron-deficient women but not among women with elevated iron stores in early pregnancy.
The evidence for a 14% relative reduction in preterm birth for zinc compared with placebo was primarily represented by trials involving women of low income and this has some relevance in areas of high perinatal mortality. There was no convincing evidence that zinc supplementation during pregnancy results in other useful and important benefits. Since the preterm association could well reflect poor nutrition, studies to address ways of improving the overall nutritional status of populations in impoverished areas, rather than focusing on micronutrient and or zinc supplementation in isolation, should be an urgent priority.