A randomized, placebo-controlled trial of the effect of zinc supplementation during pregnancy on pregnancy outcome in Bangladeshi urban poor. Effects of zinc supplementation during pregnancy on pregnancy outcome in women with history of preterm delivery: a double-blind randomized, placebo-controlled trial. Randomized controlled trial of prenatal zinc supplementation and the development of fetal heart rate. Zinc supplementation during pregnancy: a double blind randomised controlled trial. Adolescent pregnancy: associations among body weight, zinc nutriture, and pregnancy outcome. Trial of zinc supplements in relation to pregnancy outcomes, hematologic indicators, and T cell counts among HIV-1-infected women in Tanzania. Effect of prenatal zinc supplementation on birthweight. Adding zinc to prenatal iron and folate supplements improves maternal and neonatal zinc status in a Peruvian population. Zinc supplementation, mental development and behaviour in low birth weight term infants in northeast Brazil. Zinc supplementation during pregnancy: a double blind randomised controlled trial. World Health Organization randomized trial of calcium supplementation among low calcium intake pregnant women. Zinc supplementation during pregnancy: effects on selected blood constituents and on progress and outcome of pregnancy in low-income women of Mexican descent. A randomised, double-blind placebo-controlled trial of ascorbic acid supplementation for the prevention of preterm labour. Effect of zinc supplementation on development and growth of Chilean infants.
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. 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. 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. 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. 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. In observational studies, the zinc status of HIV-infected persons has been associated with both positive and adverse clinical outcomes. Such endpoints may affect the risk of adverse birth outcomes among HIV-infected women.
                We examined the effects of zinc supplements on birth outcomes, hematologic indicators, and counts of T lymphocyte subsets among 400 HIV-infected pregnant women.
                Eligible women between 12 and 27 wk of gestation were randomly assigned to daily oral supplementation with either 25 mg Zn or placebo between recruitment and 6 wk after delivery. All women received iron, folic acid, and multivitamin supplements irrespective of the experimental assignment.
                We observed no significant differences in birth weight, duration of gestation, or fetal and neonatal mortality between women in the zinc and placebo groups. Hemoglobin concentrations increased between baseline and 6 wk postpartum in both groups. However, the rise in hemoglobin over this period was significantly lower (P = 0.03) in the zinc group (x +/- SD: 11.5 +/- 17.9 g/L) than in the placebo group (15.2 +/- 18.6 g/L). Similarly, the changes in red blood cell count and in packed cell volume over the same period were significantly lower in the zinc group (P < 0.01 and P = 0.01, respectively). Zinc had no effect on CD4(+), CD8(+), or CD3(+) cell counts during the follow-up period.
                Because of the lack of beneficial effects of zinc on adverse pregnancy outcomes and the likelihood of negative effects on hemoglobin concentrations, no compelling evidence exists to support the addition of zinc to prenatal supplements intended for pregnant HIV-infected women. 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. 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. To test whether zinc supplementation reduces the deficits in mental development and behaviour that are found in term infants of low birth weight in the study population.
                A prospective double-blind, part-randomised efficacy trial.
                A low-income population in Pernambuco, northeast Brazil, where the economy is largely dependent on sugar-cane production, and where over 90% of deliveries occur in health facilities.
                During a 20-month period, all singleton, term infants weighing 1500-2499 g born to families of low income ( < US $280/month) were enrolled at birth (n = 205). At 6 and 12-months, the numbers tested were 163 and 138 respectively.
                Infants born from January 1993-January 1994 were randomly assigned to receive daily, except Sundays, a placebo (n = 66) or 1 mg zinc (n = 68). Those born February-August 1994 were given 5 mg zinc (n = 71). Supplementation was for eight weeks, starting at birth. Field workers visited each infant at home to administer the supplement.
                At 6 and 12-months, mental and psychomotor development was assessed with the Bayley Scales of Infant Development and no significant differences in the scores of the three groups were found. At 12-months, behaviour was also assessed on 5 ratings. Ratings were highest in infants given 5 mg zinc (P = 0.042).
                Zinc supplementation (5 mg/d) for eight weeks may reverse some of the poor behaviours, particularly responsiveness, exhibited by low birth weight infants. No amelioration of their mental and psychomotor deficits was found. 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 purpose of this trial was to determine whether calcium supplementation of pregnant women with low calcium intake reduces preeclampsia and preterm delivery.
                Randomized placebo-controlled, double-blinded trial in nulliparous normotensive women from populations with dietary calcium < 600 mg/d. Women who were recruited before gestational week 20 received supplements (1.5 g calcium/d or placebo) throughout pregnancy. Primary outcomes were preeclampsia and preterm delivery; secondary outcomes focused on severe morbidity and maternal and neonatal mortality rates.
                The groups comprised 8325 women who were assigned randomly. Both groups had similar gestational ages, demographic characteristics, and blood pressure levels at entry. Compliance were both 85% and follow-up losses (calcium, 3.4%; placebo, 3.7%). Calcium supplementation was associated with a non-statistically significant small reduction in preeclampsia (4.1% vs 4.5%) that was evident by 35 weeks of gestation (1.2% vs 2.8%; P = .04). Eclampsia (risk ratio, 0.68: 95% CI, 0.48-0.97) and severe gestational hypertension (risk ratio, 0.71; 95% CI, 0.61-0.82) were significantly lower in the calcium group. Overall, there was a reduction in the severe preeclamptic complications index (risk ratio, 0.76; 95% CI, 0.66-0.89; life-table analysis, log rank test; P = .04). The severe maternal morbidity and mortality index was also reduced in the supplementation group (risk ratio, 0.80; 95% CI, 0.70-0.91). Preterm delivery (the neonatal primary outcome) and early preterm delivery tended to be reduced among women who were < or = 20 years of age (risk ratio, 0.82; 95% CI, 0.67-1.01; risk ratio, 0.64; 95% CI, 0.42-0.98, respectively). The neonatal mortality rate was lower (risk ratio, 0.70; 95% CI, 0.56-0.88) in the calcium group.
                A 1.5-g calcium/day supplement did not prevent preeclampsia but did reduce its severity, maternal morbidity, and neonatal mortality, albeit these were secondary outcomes. 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). In a previous study from this institution, patients at high risk for preterm labour were screened for the presence of bacterial vaginosis (BV). When BV was present, they were randomised to receive either treatment (metronidazole) or placebo (vitamin C). There were significantly more patients with preterm labour in the metronidazole group. The aim of this double-blind randomised placebo-controlled trial study was to determine whether vitamin C could indeed reduce the recurrence risk of preterm labour. Patients with a history of preterm labour in a preceding pregnancy were randomised to receive 250 mg vitamin C or a matching placebo twice daily until 34 weeks' gestation. They attended a dedicated premature labour clinic. Significantly more women delivered before term in the group that received vitamin C, but there was no difference in the outcome of the babies between the two groups. Supplementation with vitamin C did not prevent premature labour. To evaluate the effect of zinc supplementation on growth and development during infancy.
                We randomized 150 term neonates of low socioeconomic status to receive supplemental zinc 5 mg/d (SG) or a lactose placebo (PG); 112 completed a 1-year follow-up. All were breast-fed and given cow milk formula after weaning; solid foods and iron were added at 5 months. Anthropometry measured monthly, psychomotor development (PDI), mental development (MDI), and behavior including motor quality factor were assessed by Bayley Scales at 6 and 12 months. The groups were comparable in maternal characteristics, birth weight, home environment, and mother-infant interaction.
                No effects of zinc on weight, length, and weight for length at 12 months were found controlling for sex and breast-feeding. The mean PDI (SG: 84.5 +/- 11.5 vs PG: 87.6 +/- 9.9) and MDI (90.9 +/- 10.5 vs 88.9 +/- 9.1) were similar; however, 46 of 52 infants in the PG scored <100 in MDI vs 42 of 57 in the SG (P <.05). A smaller proportion of the SG, 2 of 57, scored low in motor quality factor at 6 months compared with the PG, 8 of 52 (P =.02). The mean at 12 months for the SG was 31.9 +/- 2.8 and for the PG 30.8 +/- 2.9 (P <.05); zinc supplementation entered the multiple regression at 12 months (P =.037).
                Zinc supplementation may have a beneficial effect on mental development and motor quality behavior of healthy term infants.
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.