Zinc deficiency in pregnancy and fetal outcome

Maternal zinc deficiency during pregnancy has been related to adverse effects on progeny, and there are data showing that mild to moderate zinc deficiency (as assessed by available indicators) is quite common in the developing world. Observational data relating zinc deficiency to adverse fetal outcome have produced conflicting results, mainly because of the lack of a valid indicator of zinc deficiency in pregnancy. Studies of human pregnancy and zinc supplementation, including those from developing countries, have failed to document a consistent beneficial effect on fetal growth, duration of gestation, and early neonatal survival. Preliminary results from unpublished studies in developing countries have also proven to be discouraging. However, recent data and some preliminary findings indicate a beneficial effect of maternal zinc supplementation on neonatal immune status and infant morbidity from infectious diseases, and there is also preliminary evidence that, zinc supplementation may prevent congenital malformations (cleft lip/palate). With respect to neurobehavioral development, the evidence is conflicting, with only one study reporting a positive outcome. More research is required to assess the benefits of the large-scale introduction of zinc supplementation during pregnancy on congenital malformations, immune functions, neurobehavior, and overall neonatal survival in countries where zinc deficiency is a problem. Currently available information does not support the routine use of zinc supplementation to improve pregnancy outcome.     

Effect of maternal protein and/or energy deficiency during pregnancy on catecholamines and serotonin in fetal rat brain.

An investigation was made of the effect of maternal protein and/or energy deficiency during pregnancy on developmental changes in the levels of catecholamines and serotonin in fetal brain. Pregnant rats were fed on a 20%, 6% or 0% casein diet from day 1 of pregnancy to the day of autopsy (day 18, 20 or 22 of pregnancy). In the control group, the catecholamine content of the brain increased during pregnancy, being 21 ng on day 18, 48 ng on day 20 and 52 ng on day 22. A similar increase was found in the group on a 6% casein diet. In contrast, with complete protein deprivation there was no developmental increase in catecholamine. A slight increase in serotonin and a marked increase in 5-hydroxyindole acetic acid occurred during late pregnancy, irrespective of the maternal diet. At term, the levels of norepinephrine and dopamine and the tyrosine hydroxylase activity in the forebrain, cerebellum and brain stem of the fetuses in the group on a 0% casein diet were significantly less than those in the groups on 20% and 6% casein diets. The free tyrosine concentrations (mumol/g) in the brain of fetuses in the groups on 20%, 6% and 0% casein diets were 0.701, 0.213 and 0.661, respectively. From the above results it is concluded that the low catecholamine content of the brain in fetuses in the group on a 0% casein diet was due to disturbance of the system for catecholamine synthesis, rather than to deficiency of precursors.     

High caffeine consumption in the third trimester of pregnancy: gender-specific effects on fetal growth

It has been suggested that a high caffeine intake in pregnancy may be a risk factor for fetal growth retardation. We have tested this hypothesis in a population-based case-control study. Caffeine intake among 111 mothers of small-for-gestational-age (SGA) infants (56 boys, 55 girls) was compared with the intake among 747 mothers of non-SGA infants (368 boys, 379 girls). Food records for 3 days were collected in the second (week 17-20) and in the third (week 33) trimester, and caffeine intake from coffee, tea, soft drinks and chocolate was calculated and dichotomised as low or high, based upon the median value. Mothers of SGA infants had higher mean intake of caffeine [281 +/- 210 (SD) mg/day] in the third trimester than mothers of non-SGA infants (212 +/- 150 mg/day; P < 0.001). The risk of SGA birth was nearly doubled if the mother had a high rather than a low caffeine intake in the third trimester [odds ratio (OR) 1.8; 95% confidence intervals (CI) 1.2, 2.5]. The increased risk was mainly found in boys (OR 2.8; 95% CI 1.5, 5.2), and not in girls (OR 1.2; 95% CI 0.7, 2.1). The increased risk for boys persisted after adjustment for cigarette smoking alone, or for smoking and various other SGA risk factors together. Our results suggest that a high caffeine intake in the third trimester may be a risk factor for fetal growth retardation, in particular if the fetus is a boy.     

晚期妊娠羊水过少与胎儿窘迫的相关性分析

目的:分析临床诊断的晚期妊娠羊水过少与胎儿窘迫的关系,指导临床治疗,降低围生儿死亡率。方法:对2005年4月～2008年9月普爱医院收治晚期妊娠羊水过少孕妇220例进行回顾性分析。结果:羊水过少合并胎儿窘迫发生率呈时间相关性,随着孕周的增加其羊水过少合并胎儿窘迫发生比率增高。结论:晚期妊娠羊水过少与胎儿窘迫有一定的相关性,都应加以重视,一旦确诊羊水过少,甚至合并胎儿窘迫若胎儿已足月,除有畸形外,可尽早剖宫产终止妊娠。     

160例妊娠晚期亚临床甲状腺功能减退症孕妇的妊娠及胎儿结局分析

目的分析160例妊娠晚期亚临床甲状腺功能减退症(SCH)孕妇的妊娠及胎儿结局,为临床防治SCH提供参考依据。方法选取2014年1月-2016年10月银川市妇幼保健院收治的160例预行分娩的SCH孕妇作为观察组,另选取同期来院预行分娩的120例妊娠晚期无SCH的正常孕妇作为对照组。观察并比较两组孕妇的妊娠结局及胎儿结局。结果两组孕妇的贫血、妊娠期高血压疾病、妊娠期糖尿病、胎膜早破、先兆流产发生率比较,差异均有统计学意义(均P0.05);两组孕妇的前置胎盘、低蛋白血症、胎盘早剥、肝内胆汁淤积症、产后出血发生率比较,差异均无统计学意义(均P0.05)。两组胎儿宫内窘迫、早产发生率比较,差异均有统计学意义(均P0.05);两组出生体质量、胎龄、胎儿宫内生长受限、胎儿畸形、新生儿窒息、死胎发生率比较,差异均无统计学意义(均P0.05)。妊娠晚期合并SCH是孕妇贫血、妊娠期高血压疾病、妊娠期糖尿病、胎膜早破、先兆流产、胎儿宫内窘迫、早产等不良妊娠结局的危险因素。结论妊娠晚期SCH是导致不良妊娠结局的危险因素,孕妇发生贫血、妊娠期高血压疾病、妊娠期糖尿病、胎膜早破及先兆流产的风险较高,易引起胎儿宫内窘迫与早产。妊娠晚期SCH孕妇需及早接受干预治疗,以改善妊娠结局。     

Pyrithiamine-induced thiamine deficiency: effects on rat myelination.

Pyrithiamine was administered to newborn rats throughout the vulnerable period for myelinogenesis. A major metabolic defect was produced in the cerebral activities of the thiamine-dependent enzymes, transketolase and pyruvate decarboxylase. In spite of a defect in carbohydrate metabolism which is lethal in adult rats, overall development, and myelination as indicated by biochemical and morphological criteria, proceeded at an essentially normal rate. These findings indicate alternative metabolic pathways may be operational in newborn rat brain enabling it to circumvent major blockage in thiamine-dependent reactions.     

Zinc deficiency in pregnant rhesus monkeys: effects on behavior of infants.

Zinc deprivation from day 110 to 150 of gestation in rhesus monkeys resulted in rash, alopecia, anorexia, decreased feed efficiency, and low plasma zinc in the mothers. Infants of the dams that had been deprived of zinc during gestation displayed a more rapid postnatal growth rate than infants of the control mothers. Infants of the zinc-deprived dams played and explored less than the control infants. They also associated with their mothers a greater percentage of the time and were less active. This study has shown that third trimester maternal zinc deprivation in nonhuman primates can impair behavioral development of offspring.     

孕期亚临床维生素A缺乏对胎鼠肺形态发育的影响

【目的】 探讨孕期亚临床维生素A(vitamin A,VA)缺乏对胎鼠肺形态发育的影响。 【方法】 建立孕期VA正常(vitamin A normal,VAN)和亚临床缺乏(marginal vitamin A deficiency,MVAD)动物模型,每组均于孕19 d剖宫取胎鼠,比较其体重、肺重、肝重和肺组织VA含量及其肺视黄酸受体(retinoic acid receptor,RAR)mRNAs的表达,HE染色光镜观察胎鼠肺的形态结构。 【结果】 1)胎鼠基本情况的比较 体重、肺重和肝重三个指标VAN组均显著高于MVAD组(P<0.05);2)胎肺大体形态比较 低倍镜(×200)与高倍镜(×400)下观察结果显示,VAN组肺泡样结构分布较规则,肺泡间隔较薄,肺实质发育较好,肺间质毛细血管较丰富,肺泡2型细胞较明显,大多处于小管期;而MVAD组上述指标均相对较差,发育幼稚,局部为小管期,大多为假腺体期;3)胎鼠肺单位组织VA水平 VAN组>MVAD组,差异均有统计学意义(P<0.05);4)胎鼠肺RAR-α、RAR-γ和RAR-β mRNAs表达水平VAN组P<0.05)。 【结论】 孕期VA水平不同能影响胎鼠基本发育、胎肺形态结构、肺单位组织VA水平及其RAR mRNAs的表达;孕期MVAD时其胎肺发育相对较差。     

Essential fatty acid deficiency during pregnancy in the rat: influence of dietary carbohydrates

We investigated the role of gestation in the development of essential fatty acids (EFA) deficiency by comparing four groups of nonpregnant rats and four groups of pregnant rats fed either glucose or sucrose as carbohydrate source (61.5% kJ) and either corn oil (EFA) or hydrogenated coconut oil [saturated fat (SF)] as fat source (5% kJ). Pregnancy was a crucial period for the onset of EFA deficiency in sucrose-fed rats. The arachidonic acid content of plasma lipids and liver microsomes was lower in SF-sucrose pregnant rats than in SF-sucrose nonpregnant rats. The liver microsome delta 6- and delta 5-desaturase activities were higher in sucrose pregnant rats than in sucrose nonpregnant rats. In glucose-fed rats the EFA deficiency was less severe. delta 6- and delta 5-desaturase activities were higher in SF-glucose rats than in EFA-glucose rats, except for delta 5-desaturase of the pregnant rats, in which activity was high in both glucose-fed groups. This might explain the effect of glucose in preventing the onset of EFA-deficiency in pregnant rats fed an SF diet.     

Caffeine consumption during pregnancy and fetal growth.

BACKGROUND: The purpose of this study was to examine the association between maternal caffeine consumption and low birthweight, intrauterine growth retardation, and prematurity, adjusting for multiple confounders. METHODS: Data obtained from birth certificates and interviews on 1,230 women with singleton live births were analyzed to evaluate the potential influence of caffeine consumption during the first trimester on fetal growth. RESULTS: The crude odds ratio for intrauterine growth retardation in infants of women reporting heavy caffeine consumption (greater than 300 mg/day) was 3.86 (95% CI = 1.80, 8.40) which decreased to 2.90 (95% CI = 1.23, 6.87) after controlling for confounding factors. The adjusted odds ratio for low birthweight and heavy maternal caffeine consumption was also elevated (OR = 2.05; 95% CI = 0.86, 4.88). Women who reduced their caffeine intake from greater than 300 mg/day to less than that early in pregnancy had lower risks of delivering infants with either intrauterine growth retardation or low birthweight than women who continued to consume that amount. Preterm delivery appeared to be unrelated to caffeine consumption. CONCLUSIONS: Taken together with studies reporting similar findings, these results suggest that heavy caffeine consumption increases the risk for fetal growth retardation.     

Severe vomiting during pregnancy: antenatal correlates and fetal outcomes.

Neither the cause nor the effect of severe vomiting during pregnancy is well understood. This study examines possible causes of severe vomiting and associations between this disorder and fetal outcomes. One thousand eight hundred sixty-seven women with normal singleton live births were included in the analysis. The cumulative incidence of severe vomiting during pregnancy was 10.8%. Women with chronic liver disease had a threefold increased risk of severe vomiting during pregnancy. Paternal smoking was associated with a twofold increased risk of maternal vomiting. A modest association between severe vomiting and fetal growth retardation was identified (OR = 1.4, 95% CI: 0.9-2.3). Severe vomiting was also found to be associated with preeclampsia (OR = 1.5, 95% CI: 1.0-2.4). Our study indicates that passive smoking is a risk factor for vomiting during pregnancy, which may, in turn, increase the risk of fetal growth retardation.     

Vitam A deficiency and fetal growth and development in the rat.

Studies were conducted to examine in detail the effects of vitamin A deficiency on fetal growth and development in the rat. The gradations of deficiency were examined in two studies. The first included total vitamin A depletion followed by retinoic acid supplements, and the second included three different levels of restricted intake of retinyl acetate (42, 16, or 8 mug of retinol equivalents/day/kg of body weight) in vitamin A-depleted rats. In the first study, extensive fetal resorption and death were observed in retinoic acid-fed females after day 14 of gestation. These findings confirmed the morphological studies of Thompson and associates (Proc. Roy. Soc. London, Ser. B 159, 510-535, 1964) who found the earliest Detectable histological lesions to be in the placentas at days 15-16 of pregnancy. Analyses were carried out of the total weight, the DNA, RNA, and protein contents of fetuses and placentas of different gestational ages in retinyl ester-fed and retinoic acid-fed females. Biochemical changes indicative of a reduced rate of cell division were observed in both fetus and placenta by day 14 in the retinoic acid-fed rats. The few live fetuses in this group maintained a growth rate of only 60-70% of that of the fetuses of retinyl ester-fed dams after day 14. By contrast, the growth rate of the placentas (of live fetuses) after day 14 of gestation was not as consistently affected by retinol deficiency. Restriction of retinyl acetate intake (in the second study) significantly reduced both the total litter size and the number of live pups per litter. Most of the females in the retinyl acetate-restricted groups delivered pups that had normal body weight and appeared normal on visual inspection. Significant differences from normal controls were seen only in the neonates from dams given 8 mug of retinol equivalents (per kg of body weight per day), which had smaller livers and kidneys than the control neonates. In contrast, the weights of the brains of the neonates in all three retinyl acetate-restricted groups showed no differences from control values. Vitamin A assays on maternal and neonatal sera and livers indicated that the transport of vitamin A across the placenta was well regulated, and suggested that this transport is maintained with high priority in the presence of maternal deficiency. The effects of vitamin A deficiency on fetal growth and development might reflect primary effects on the placenta, with secondary effects on the fetus, or primary direct effects on the fetus itself. The mechanisms of the observed effects remain to be explained.     

Zinc supplementation during pregnancy: effects on selected blood constituents and on progress and outcome of pregnancy in low-income women of Mexican descent

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).     

Zinc supplementation during pregnancy in low-income teenagers of Mexican descent: effects on selected blood constituents and on progress and outcome of pregnancy

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.     

Protein-energy malnutrition in rats during pregnancy modifies the effects of caffeine on fetal bones

The mandibles and long bones of newborn rats were analyzed for the effects of maternal caffeine consumption and protein-energy malnutrition. On d 13 of gestation, dams were randomly picked and divided into four groups. Group 1 received a 20% protein diet ad libitum. Group 2 was pair-fed with group 1 a 20% protein diet with a caffeine supplement (2 mg/100 g body wt). Group 3 received a 6% protein diet ad libitum. Group 4 was pair-fed with group 3 a 6% protein diet with caffeine. Within 8 h of delivery, all pups were weighted. Randomly selected pups were injected with 14C proline to study collagen synthesis of bones. Other pups were injected with 45Ca to study mineralization of bones. Although the average litter size from the 20% protein groups with or without caffeine did not show much variation, fetal resorption and stillbirths were higher in litters from group 4 compared to those from group 3. The mandibular weights of pups from group 2 was less than those from group 1, whereas weight of long bones of those from group 4 was heavier. The rate of collagen synthesis and calcium content of the mandible of group 4 and 45Ca uptake of the mandible of groups 2 and 4 were greater than that of the corresponding noncaffeine group. The rate of collagen synthesis, hydroxyproline content, 45Ca uptake and calcium content of the long bones of groups 2 and 4 were greater than that of the noncaffeine groups. The findings suggest that nutritional factors and the effects of caffeine are closely interrelated in the growth and development of the fetus and bone in newborn rats.