Plasma zinc in hypertension/toxemia and other reproductive variables in adolescent pregnancy

Analysis of serum calcium, sodium, potassium, zinc, and iron in patients with pre-eclampsia in Bangladesh: A case-control study

Background and Aims

Pre-eclampsia is a particular type of pregnancy condition. Although the primary etiology of pre-eclampsia is unclear, it hypothesizes that the alteration of trace elements and macro-minerals may play a crucial function in the pathogenesis of Pre-eclampsia. Therefore, our research sought to ascertain the serum level of trace elements (zinc, iron) and macro-minerals (sodium, calcium, potassium) and their possible association with pre-eclampsia.

Methods

The present study was conducted with 74 pre-eclampsia pregnant women (case) and 118 pregnant women having normal blood pressure (controls). Atomic Absorption Spectroscopy determined the serum level of trace components and electrolytes.

Results

The researchers discovered notable differences in maternal age, gestational period, body mass index, systolic and diastolic blood pressure, hemoglobin, and creatinine level. Results of serum analysis revealed that calcium (52.06 ± 3.71 mg/L vs. 65.93 ± 2.57 mg/L, p < 0.05) and potassium (63.44 ± 5.33 mg/L vs. 102.54 ± 4.25 mg/L, p < 0.001) concentrations were substantially lower in the patient group than in control. Serum zinc (0.34 ± 0.02 mg/L vs. 0.52 ± 0.02 mg/L, p < 0.001) and iron (0.38 ± 0.03 mg/L vs. 0.46 ± 0.02 mg/L, p < 0.05) concentration were also considerably decreased in pre-eclampsia participants compared with a pregnant normotensive group. Pearson's correlation research results in the patient group revealed a connection between trace elements or macro minerals. In addition, the systolic blood pressure was positively correlated with sodium (r = 0.392, p < 0.01) and negatively correlated with potassium (r = -0.257, p < 0.05) in the control group.

Conclusions

This study concludes that calcium, potassium, iron, and zinc levels were lower, whereas sodium levels were higher in Bangladeshi pre-eclampsia patients compared to controls. These findings with Pearson's correlation and the inter-element relationship between the patient and a control subject results can act as critical indication factors for patients with pre-eclampsia in Bangladesh and, as a result, may require a higher intake of calcium, potassium, iron, and zinc for effective therapeutic intervention and reduce the intake of sodium.

Is the Tradeoff between Folic Acid or/and Multivitamin Supplementation against Birth Defects in Early Pregnancy Reconsidered? Evidence Based on a Chinese Birth Cohort Study

BACKGROUND

Several studies have reported conflicting results on the association between maternal exposure to folic acid (FA) and/or multivitamin (MV) supplements and the risk of birth defects (BDs), especially for different subtypes of BDs. The present study aimed to identify the association between maternal exposure to FA or/and MV and BDs in offspring.

METHODS

In the Chinese Birth Cohort Study initiated from 20 November 2017, 120,652 pregnant women completed follow-up until 20 August 2021. The participants were classified into four groups: without exposure to FA and MV, exposure to only FA, exposure to only MV, and exposure to FA and MV. Birth defects were coded by the International Classification of Diseases (ICD)-10. In order to explore the structural relationship between maternal FA or MV supplements and BDs, directed acyclic graphs were drawn. Then, an inverse probability treatment weighting was utilized to reduce the systematic differences in the baseline characteristics among the different groups. Lastly, a two-level mixed-effect log binomial regression analysis was used to estimate the relative risk (RR) value of the different subtypes of BDs under different exposures to FA and/or MV.

RESULTS

Compared with the maternal group without exposure to FA and MV, the RR values of nervous system defects, face, ear, and neck defects, limb defects, and CHDs in the maternal group with only FA supplementation were less than 1.0, but they were not statistically significant. The RR values of genitourinary defects, abnormal chromosomes, and oral clefts were more than 1.0, and they were also not statistically significant. However, the risk of genitourinary defects (RR: 3.22, 95% CI: 1.42-7.29) and chromosomal abnormalities (RR: 2.57, 95% CI: 1.16-5.73) in the maternal group with only MV supplementation increased more than those in the maternal group without exposure to FA and MV. In addition, the RR values of all subtypes of BDs in the maternal group with exposure to FA and MV were closer to 1.0 than those in maternal group with exposure to only MV, but they were not statistically significant.

CONCLUSIONS

It was indicated that the simultaneous supplementation of FA and MV in early pregnancy may have an interaction for the prevention of BDs and may have inconsistent effects for different subtypes of BDs. At the same time, excessive FA supplementation in pregnant women may increase the risk of BDs in their offspring. Although the mechanism is not clear, this evidence reminded us that more trade-offs are necessary for formulating strategies for the prevention of BDs with FA and/or MV supplementation in early pregnancy.

Association of selenium, zinc and copper concentrations during pregnancy with birth weight: A systematic review and meta-analysis

BACKGROUND

Normal fetal growth is associated with maternal nutrition. Trace elements play important roles in fetus growth. This review aims to provide a summary of the literature evaluating the relation between selenium, zinc and copper levels during pregnancy with birth weight.

METHOD

A systematic literature search was conducted in Medline database (PubMed), Scopus, Web of science and Google scholar up to September 2020. Fifty observational studies were included in the final analyses. The desired pooled effect size was considered as standardized mean differences with 95 % CI or correlation. Cochran's Q statistic was used to test the heterogeneity between the included studies (I²).

RESULT

A significant differences were found between pooled standardized mean differences (SMD) of umbilical cord blood copper levels in small-for-gestational age birth weight (SGA) and appropriate-for-gestational age birth weight (AGA) (SMD: 0.34 μg/L, 95 % CI: 0.13 to 0.56). There was a significant pooled correlation between umbilical cord blood selenium concentrations and birth weight (r: 0.08, 95 % CI: 0.01 to 0.16). A significant pooled correlation was found between umbilical cord blood zinc concentrations and birth weight (r: 0.09, 95 % CI: 0.04 to 0.15), with significant heterogeneity (I² % = 0.63). There was significant positive association between maternal blood zinc concentrations and birth weight.

CONCLUSION

Findings showed the association of trace elements including selenium, zinc and copper during pregnancy with birth weight. There was significant correlation between umbilical cord and maternal blood selenium and zinc levels with birth weight. The umbilical cord blood copper levels in SGA birth weight was higher than copper levels in AGA birth weight.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy, such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although these associations have not yet been established. This is an update of a review first published in 1997 and subsequently updated in 2007, 2012 and 2015.

OBJECTIVES

1. To compare the effects on maternal, fetal, neonatal and infant outcomes in healthy pregnant women receiving zinc supplementation versus no zinc supplementation, or placebo. 2. To assess the above outcomes in a subgroup analysis reviewing studies performed in women who are, or are likely to be, zinc-deficient.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (3 July 2020), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation versus no zinc supplementation or placebo administration during pregnancy, earlier than 27 weeks' gestation. We excluded quasi-randomised controlled trials. We intended to include studies presented only as abstracts, if they provided enough information or, if necessary, by contacting authors to analyse them against our criteria; we did not find any such studies.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

For this update, we included 25 randomised controlled trials (RCTs) involving over 18,000 women and their babies. The overall risk of bias was low in half of the studies. The evidence suggests that zinc supplementation may result in little or no difference in reducing preterm births (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.74 to 1.03; 21 studies, 9851 participants; low-certainty evidence). Further, zinc supplementation may make little or no difference in reducing the risk of stillbirth (RR 1.22, 95% CI 0.80 to 1.88; 7 studies, 3295 participants; low-certainty evidence), or perinatal deaths (RR 1.10, 95% CI 0.81 to 1.51; 2 studies, 2489 participants; low-certainty evidence). It is unclear whether zinc supplementation reduces neonatal death, because the certainty of the evidence is very low. Finally, for other birth outcomes, zinc supplementation may make little or no difference to mean birthweight (MD 13.83, 95% CI -15.81 to 43.46; 22 studies, 7977 participants; low-certainty evidence), and probably makes little or no difference in reducing the risk of low birthweight (RR 0.94, 95% CI 0.79 to 1.13; 17 studies, 7399 participants; moderate-certainty evidence) and small-for-gestational age babies when compared to placebo or no zinc supplementation (RR 1.02, 95% CI 0.92 to 1.12; 9 studies, 5330 participants; moderate-certainty evidence). We did not conduct subgroup analyses, as very few studies used normal zinc populations.

AUTHORS' CONCLUSIONS

There is not enough evidence that zinc supplementation during pregnancy results in improvements in maternal or neonatal outcomes. Future research to address ways of improving the overall nutritional status of pregnant women, particularly in low-income regions, and not looking at zinc in isolation, should be an urgent priority.

Zinc Levels and Birth Weight in Pregnant Women with Gestational Diabetes Mellitus: A Matched Cohort Study in China

BACKGROUND

Zinc (Zn) has been suggested to impact fetal growth. However, the effect may be complicated by gestational diabetes mellitus (GDM) due to its impact on fetal growth and placental transport. This study aims to investigate whether GDM modifies the association between Zn levels and birth weight.

METHOD

A cohort matched by GDM was established in Taiyuan, China, between 2012 and 2016, including 752 women with GDM and 744 women without. Dietary Zn intake was assessed during pregnancy. Maternal blood (MB) and cord blood (CB) Zn levels were measured at birth. Birth weight was standardized as the z score and categorized as high (HBW, >4000 g) and low (LBW, <2500 g) groups. Multivariate linear regression and multinomial logistic regression were used to examine the association between Zn levels and birth weight in offspring born to women with or without GDM.

RESULTS

88.8% (N = 1328) of the population had inadequate Zn intake during pregnancy. In women with GDM, MB Zn level was inversely associated with birth weight (β = -.17; 95% confidence interval (CI), -0.34 to -0.01), while CB Zn level was positively associated with birth weight (β = .38; 95% CI, 0.06-0.70); suggestive associations were observed between MB Zn level and LBW (odds ratio 2.01; 95% CI, 0.95-4.24) and between CB Zn level and HBW (odds ratio 2.37; 95% CI, 1.08-5.21).

CONCLUSIONS

GDM may modify the associations between MB and CB Zn levels and birth weight in this population characterized by insufficient Zn intake. These findings suggest a previously unidentified path of adverse effects of GDM.

Combined Effects of Gestational Phthalate Exposure and Zinc Deficiency on Steroid Metabolism and Growth

Disruption of steroid hormone signaling has been implicated independently in the developmental abnormalities resulting from maternal phthalate plasticizer exposure and developmental zinc deficiency. This study investigated if secondary zinc deficiency may result from dietary exposure to a low level of di-2-ethylhexyl phthalate (DEHP) through gestation and if this could be associated with altered steroid metabolism. The interaction between marginal zinc nutrition and DEHP exposure to affect pregnancy outcome, zinc status, and steroid metabolism was also assessed. For this purpose, rats were fed a diet containing an adequate (25 mg/kg) or marginal (10 mg/kg) level of zinc without or with DEHP (300 mg/kg) from gestation day (GD) 0 until GD 19. Steroid profiles were measured in dam liver, plasma, adrenal glands, and in fetal liver by UPLC/MS-MS. In dams fed the adequate zinc diet, DEHP exposure decreased maternal weight gain and led to hepatic acute-phase response and zinc accumulation. The latter could compromise zinc availability to the fetus. DEHP and marginal zinc deficiency caused several adverse effects on the maternal and fetal steroid profiles. Interactions between DEHP exposure and marginal zinc deficient nutrition affected 17OH pregnenolone and corticosterone, while pregnenolone levels were specifically affected by DEHP exposure. Maternal marginal zinc deficiency specifically affected maternal progesterone and aldosterone, and presented evidence of increased androgen aromatization activity in maternal and fetal tissues. Results stress the potential major impact of mild DEHP exposure on maternal/fetal steroid metabolism that can be potentiated by nutritional and chronic disease states leading to zinc deficiency.

Alterations in Lipid Profile, Zinc and Copper Levels and Superoxide Dismutase Activities in Normal Pregnancy and Preeclampsia

BACKGROUND

Increased oxidative stress (OS) and lipid peroxidation may be involved in the pathogenesis of preeclampsia (PE). We conducted a case-control study to evaluate the levels of plasma lipids and trace elements as well as activity of superoxide dismutase (SOD) in PE.

MATERIALS AND METHODS

The study consisted of 100 patients who had been diagnosed with PE and 100 normotensive pregnant women who underwent medical checkups that served as the control group. Lipid profile, zinc (Zn) and copper (Cu) levels and SOD activities were measured in the plasma of all subjects.

RESULTS

Our results showed that the plasma levels of triglycerides and SOD activity were significantly elevated and the levels of Zn and Cu were significantly reduced in patients with PE compared with healthy controls. Increased levels of SOD may indicate antioxidant protective mechanisms against OS in PE-complicated pregnancies. This finding may suggest an involvement of OS in the pathophysiology of PE.

CONCLUSION

This study demonstrated a significant negative correlation between SOD activity and levels of trace elements. Furthermore, we suggest that higher triglyceride levels and SOD activity combined with lower Zn and Cu levels may be associated with an increased risk of PE.

Association between Maternal Zinc Status, Dietary Zinc Intake and Pregnancy Complications: A Systematic Review

Adequate zinc stores in the body are extremely important during periods of accelerated growth. However, zinc deficiency is common in developing countries and low maternal circulating zinc concentrations have previously been associated with pregnancy complications. We reviewed current literature assessing circulating zinc and dietary zinc intake during pregnancy and the associations with preeclampsia (PE); spontaneous preterm birth (sPTB); low birthweight (LBW); and gestational diabetes (GDM). Searches of MEDLINE; CINAHL and Scopus databases identified 639 articles and 64 studies were reviewed. In 10 out of 16 studies a difference was reported with respect to circulating zinc between women who gave birth to a LBW infant (≤2500 g) and those who gave birth to an infant of adequate weight (>2500 g), particularly in populations where inadequate zinc intake is prevalent. In 16 of our 33 studies an association was found between hypertensive disorders of pregnancy and circulating zinc; particularly in women with severe PE (blood pressure ≥160/110 mmHg). No association between maternal zinc status and sPTB or GDM was seen; however; direct comparisons between the studies was difficult. Furthermore; only a small number of studies were based on women from populations where there is a high risk of zinc deficiency. Therefore; the link between maternal zinc status and pregnancy success in these populations cannot be established. Future studies should focus on those vulnerable to zinc deficiency and include dietary zinc intake as a measure of zinc status.

Evaluation of lead and essential elements in whole blood during pregnancy: a cross-sectional study

AIM

Physiological concentrations of some elements fluctuate during pregnancy due to the increased requirements of growing fetus and changes in the maternal physiology. The aim of the study is to evaluate the distribution at different stages of pregnancy in healthy Chinese women and to show the association between trace elements and gestational age-specific reference intervals.

METHODS

A cross-sectional study was performed in 1089 pregnant women and 677 nonpregnant control women. Five element concentrations, including Cu, Zn, Ca, Mg, Pb in the blood were determined by atomic absorption spectrometry. Spearman's rank correlation test was used to assess the relationship between weeks of gestation and blood element concentrations.

RESULTS

The mean levels of Cu and Mg were 23.64 ± 4.69 μmol/L and 1.36 ± 0.12 mmol/L, respectively, in the control women. While 0.68 % of all pregnant women showed Cu levels below the normal ranges, the levels of Mg were comparable in different groups. Though the overall mean blood zinc and Ca concentrations (83.84 ± 17.50 μmol/L and 1.60 ± 0.15 mmol/L, respectively) increased gradually with the progress of gestation, the Zn and Ca deficiency levels (16.6 and 3.6 %, respectively) decreased with the advance of gestation. Compared with nonpregnant group, the concentrations of Cu, Zn, Ca, Mg, Pb during the different stages of pregnancy, as a whole, were significantly different. Positive correlations were observed between weeks of gestation and blood Cu, Ca, Pb concentrations (r = 0.301, 0.221, 0.223; P < 0.05). There was a negative correlation blood Mg concentrations and weeks of gestation (r = -0.321; P < 0.05). A weak positive correlation was noted between Zn concentrations and weeks of gestation (r = 0.125; P < 0.05).

CONCLUSION

The importance of Cu and Mg deficiency and supplementation is well realized, but, Zn/Ca deficiency and Pb exposure is still exist; the overall deficiency of pregnant women was not so optimistic. During pregnancy, the established reference values will provide an important guidance for the reasonable supplementation of essential elements and surveillance of lead overexposure.

Fluctuation of potential zinc status biomarkers throughout a reproductive cycle of primiparous and multiparous sows

Fluctuations in Zn metabolism throughout gestation and lactation might affect Zn requirements. However, scientific data on Zn requirements for breeding sows are limited. The objective of the present study was to assess the Zn status of primiparous and multiparous sows using different Zn status biomarkers, to identify periods of critical Zn status throughout the reproductive cycle at different parities. Blood samples were taken after overnight fasting before feeding in the morning from five primiparous and ten multiparous sows at fixed time intervals during gestation (days - 5, 0 (insemination), 21, 42, 63 and 84), around parturition (days 108, 112, 115 (parturition) and 118) and during lactation (days 122, 129 and 143 (weaning)). At parturition, blood samples were collected from two randomly selected piglets per sow before colostrum intake. Plasma was analysed for Zn and Cu contents, whereas serum was analysed for alkaline phosphatase, metallothionein and albumin concentrations. Independently of parity, all biomarkers fluctuated differently during gestation and lactation (P< 0·050). This reflects their different roles in Zn metabolism, and suggests that the choice of a Zn status biomarker necessitates careful consideration. Low average plasma Zn concentration at the end of gestation and throughout lactation seem to be replenished towards weaning.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although many of these associations have not yet been established.

OBJECTIVES

To assess the effects of zinc supplementation in pregnancy on maternal, fetal, neonatal and infant outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2014) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation in pregnancy. We excluded quasi-randomised controlled trials.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

We included 21 randomised controlled trials (RCTs) reported in 54 papers involving over 17,000 women and their babies. One trial did not contribute data. Trials were generally at low risk of bias. Zinc supplementation resulted in a small reduction in preterm birth (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.76 to 0.97 in 16 RCTs; 16 trials of 7637 women). This was not accompanied by a similar reduction in numbers of babies with low birthweight (RR 0.93, 95% CI 0.78 to 1.12; 14 trials of 5643 women). No clear differences were seen between the zinc and no zinc groups for any of the other primary maternal or neonatal outcomes, except for induction of labour in a single trial. No differing patterns were evident in the subgroups of women with low versus normal zinc and nutrition levels or in women who complied with their treatment versus those who did not. The GRADE quality of the evidence was moderate for preterm birth, small-for-gestational age, and low birthweight, and low for stillbirth or neonatal death and birthweight.

AUTHORS' CONCLUSIONS

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.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although many of these associations have not yet been established.

OBJECTIVES

To assess the effects of zinc supplementation in pregnancy on maternal, fetal, neonatal and infant outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2011) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation in pregnancy. We excluded quasi-randomised controlled trials.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information.

MAIN RESULTS

We included 20 randomised controlled trials (RCTs) reported in 51 papers involving over 15,000 women and their babies. Trials were generally at low risk of bias. Zinc supplementation resulted in a small but significant reduction in preterm birth (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.76 to 0.97 in 16 RCTs; 16 trials of 7637 women). This was not accompanied by a similar reduction in numbers of babies with low birthweight (RR 0.93, 95% CI 0.78 to 1.12; 14 trials of 5643 women). No significant differences were seen between the zinc and no zinc groups for any of the other primary maternal or neonatal outcomes, except for induction of labour in a single trial. No differing patterns were evident in the subgroups of women with low versus normal zinc and nutrition levels or in women who complied with their treatment versus those who did not.

AUTHORS' CONCLUSIONS

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.

The importance of antioxidant micronutrients in pregnancy

Pregnancy places increased demands on the mother to provide adequate nutrition to the growing conceptus. A number of micronutrients function as essential cofactors for or themselves acting as antioxidants. Oxidative stress is generated during normal placental development; however, when supply of antioxidant micronutrients is limited, exaggerated oxidative stress within both the placenta and maternal circulation occurs, resulting in adverse pregnancy outcomes. The present paper summarises the current understanding of selected micronutrient antioxidants selenium, copper, zinc, manganese, and vitamins C and E in pregnancy. To summarise antioxidant activity of selenium is via its incorporation into the glutathione peroxidase enzymes, levels of which have been shown to be reduced in miscarriage and preeclampsia. Copper, zinc, and manganese are all essential cofactors for superoxide dismutases, which has reduced activity in pathological pregnancy. Larger intervention trials are required to reinforce or refute a beneficial role of micronutrient supplementation in disorders of pregnancies.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although many of these associations have not yet been established.

OBJECTIVES

To assess the effects of zinc supplementation in pregnancy on maternal, fetal, neonatal and infant outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (February 2007).

SELECTION CRITERIA

Randomised or quasi-randomised trials of zinc supplementation in pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, study authors were contacted for additional information.

MAIN RESULTS

We included 17 randomised controlled trials (RCTs) involving over 9000 women and their babies. Zinc supplementation resulted in a small but significant reduction in preterm birth (relative risk (RR) 0.86, 95% confidence interval (CI) 0.76 to 0.98 in 13 RCTs; 6854 women). This was not accompanied by a similar reduction in numbers of babies with low birthweight (RR 1.05 95% CI 0.94 to 1.17; 11 studies of 4941 women). No significant differences were seen between the zinc and no zinc groups for any of the other primary maternal or neonatal outcomes, except for a small effect favouring zinc for caesarean section (four trials with high heterogeneity) and for induction of labour in a single trial. No differing patterns were evident in the subgroups of women with low versus normal zinc and nutrition levels or in women who complied with their treatment versus those who did not.

AUTHORS' CONCLUSIONS

The 14% relative reduction in preterm birth for zinc compared with placebo was primarily in the group of studies 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.

Zinc and copper metabolism in pregnancy and lactation of adolescent women

OBJECTIVE

Pregnant and lactating adolescent women are at risk of zinc and copper deficiency but their capacity for metabolic adaptation is poorly known. This study investigated the effect of pregnancy and lactation on zinc and copper metabolism in adolescent women by comparing biochemical indices between groups in different reproductive states.

METHODS

Habitual dietary intake and biochemical indices (zinc, copper, alkaline phosphatase, and ceruloplasmin in plasma; zinc [E-Zn], metallothionein [E-MT], and superoxide dismutase [E-SOD] in erythrocytes) and their relation were compared among non-pregnant non-lactating adolescents (NPNLs; n = 26), third-trimester pregnant adolescents (PAs; n = 26), and lactating adolescents up to 3 mo postpartum (LAs; n = 21).

RESULTS

Zinc and copper intakes were not different across groups (on average, 8.7 and 1.0 mg/d, respectively). PAs had lower plasma zinc but higher plasma copper, alkaline phosphatase, and ceruloplasmin levels than did LAs and NPNLs (P < 0.05). E-SOD and E-Zn were similar in all groups but E-MT was higher in the PA and LA groups than in the NPNL group (P < 0.05). Correlations between plasma copper and ceruloplasmin and between E-MT and E-Zn were observed in the LA and NPNL groups (r > or = 0.64, P < 0.01) but not in the PA group. In contrast, correlations between plasma alkaline phosphatase and plasma zinc, between E-MT and plasma zinc, and between E-SOD and E-Zn were observed only in the PA group (r > or = 0.46, P < 0.05).

CONCLUSION

Zinc and copper biochemical responses to pregnancy and lactation in the adolescent women studied appeared qualitatively similar to those described in previous studies in adult women. However, the significant correlations observed between the activity of zinc-dependent enzymes and plasma (or erythrocyte) zinc suggest that a poor maternal zinc status may limit the metabolic adaptation capacity of these adolescent women especially during pregnancy.

Updating of normal levels of copper, zinc and selenium in serum of pregnant women

Selenium, copper and zinc status is important in pregnant women. The aim of this study was to establish updated normal ranges for these elements in serum of pregnant women from the Spanish region of Aragon, and to study variation in levels with respect to gestational period and maternal age. The study group consisted of 159 pregnant women who did not suffer from serious pathologies. These samples were classified into four gestational-period groups. Zn and Cu determinations were obtained by flame atomic absorption spectroscopy in a Perkin-Elmer 1100B apparatus, and Se was determined by electrothermal atomic absorption spectrometry with Zeeman correction, in a Perkin-Elmer 4110 ZL apparatus. The concentrations of Cu, Zn and Se averaged 73.61+/-43.67 microg/dL, 65.37+/-12.87 microg/dL and 99.59+/-21.74 microg/L, respectively. The Cu/Zn ratio increased from first trimester to the third trimester (2.07-3.49). There was no significant correlation between Zn and Se levels, but a significant correlation was found between Cu and Se levels (p<0.05) and between Cu and Zn levels (p<0.001). Serum Zn and Se levels decreased over gestation, while serum Cu concentrations increased; in all cases the variation occurred mostly in the first 3 or 4 months, with mean levels then remaining fairly stable until the end of pregnancy. Maternal age did not influence levels of any of the three metals.

Adverse pregnancy outcomes associated with maternal enalapril antihypertensive treatment

BACKGROUND

Adverse pregnancy outcomes following the use of angiotensin-converting enzyme (ACE) inhibitors, including enalapril, have been reported in descriptive studies. However, no analytical studies on the relationship between the adverse outcomes and enalapril gestational exposures are available.

OBJECTIVES

To explore the association between enalapril exposure and adverse outcomes in pregnancy, taking into account other possible risk factors.

METHODS

We analyzed a series of all usable cases reported to the FDA between 1986 and 2000 in which enalapril was a suspect drug for the observed adverse outcomes (N = 110). Parameters of exposure and reported outcomes as well as information on potentially confounding variables were systematically abstracted from this series by a single physician. Because exposure to ACE inhibitors after the first trimester of pregnancy had been associated with adverse outcomes in the existing literature, we divided the cases into those exposed in the first trimester only (considered as the baseline group) and cases exposed beyond or after this time. Frequency of reported adverse outcomes in the second group was compared with those in the baseline group; odds ratios were computed, taking account of potentially confounding variables by logistic regression where appropriate.

RESULTS

Exposure to enalapril after the first trimester of pregnancy was strongly associated with oligohydramnios and specific adverse outcomes thought to be secondary to reduced amniotic fluid volume (limb deformities, cranial ossification deficits, lung hypoplasia), as well as with neonatal renal failure. The relationship did not change after taking numerous potential confounders into account, including duration of exposure, concomitant drug use, maternal age, concurrent disease, neonatal gender, and gestational age at birth. Such a pattern of abnormalities is considered to be a consequence of the effect of ACE inhibition on fetal renal function that develops after the first trimester.

CONCLUSION

The specificity and temporality of the observed adverse manifestations suggest a causal relationship to enalapril exposure.

The changes of trace elements, malondialdehyde levels and superoxide dismutase activities in pregnancy with or without preeclampsia

OBJECTIVES

Increased free radical activity and lipid peroxidation may be implicated in the pathogenesis of preeclampsia. This study was initiated to assess antioxidant enzyme and trace metals's status in preeclampsia.

DESIGN AND METHODS

The comparison was made between the pregnant women with or without preeclampsia and healthy controls in this study. Samples were obtained from 24 normal nonpregnant (controls), 30 normal pregnant and 21 preeclamptic women in the third trimester. Lipid peroxidation end product, malondialdehyde (MDA), free radical scavenging enzyme activity, superoxide dismutase (SOD) and serum zinc (Zn), copper (Cu) levels were measured in either plasma/serum or erythrocytes of patients. Data were analyzed statistically using Student's t-test.

RESULTS

In the preeclamptic group malondialdehyde, Cu levels were significantly increased, while Zn and SOD levels were significantly decreased compared to normal control group and healthy pregnant women.

CONCLUSIONS

Our findings give support that radical scavenging SOD is consumed by the increased lipid peroxidation in preeclampsia. This data may indicate an involvement of free radicals in the pathophysiology of preeclampsia. This study suggests a relationship between increased MDA, Cu levels and decreased SOD, Zn levels in pregnancy and preeclampsia.

Micronutrient status during pregnancy and outcomes for newborn infants in developing countries

More than 9 million neonatal deaths occur each year, 98% of them in developing countries. Neonatal deaths account for two-thirds of deaths in infancy and 40% of deaths before age 5 y. The major direct causes of neonatal death are infections, preterm delivery and asphyxia. Important indirect causes include low birth weight and hypothermia. The present body of work on multiple micronutrient interventions is not sufficient for us to draw conclusions on their effects on neonatal well-being. Because studies have generally concentrated on single micronutrients and a range of outcomes, this paper reviews the findings for individual nutrients and then summarizes the situation. The evidence for the contribution of micronutrient deficiencies to perinatal mortality and duration of gestation is limited, and the evidence base for individual micronutrient effects on neonatal mortality and morbidity is patchy. To translate knowledge into policy, community evaluations of effect and an expanded evidence base that includes affordability, acceptability and scalability are also required. A balance between supply-side and demand-side interventions must be struck, with an emphasis on effect and sustainability. Among the key requirements are randomized, controlled community effectiveness trials of the effect of micronutrient supplementation in pregnancy on perinatal mortality and neurodevelopment, studies on improving adherence and studies on the relation between micronutrient deficiencies and sepsis and neonatal encephalopathy. It would also be helpful to look at mechanisms for bringing the periconceptional period within the ambit of trials.

Effect of gestational age on cord blood plasma copper, zinc, magnesium and albumin

BACKGROUND

The transport of essential trace elements from mother to fetus varies throughout gestation, and the role of transport proteins in the neonate and the mother may change during pregnancy. Magnesium, often used as tocolytic agent, may reach the fetus and appear in cord blood at higher than normal concentrations.

AIMS

To determine cord blood plasma zinc, copper and magnesium concentrations, as well as plasma albumin in premature and full-term newborns, and correlate these values with those of maternal blood plasma at birth. Also, to examine whether cord blood plasma concentration of these elements varies with gestational age.

SUBJECTS

The 35 mother-infant pairs included: 11 in the 38-42-week gestational age (GA), 9 in the 34-37-week GA, 11 in the 29-33-week GA group and 4 in the 24-28-week GA. Magnesium for tocolysis was given to five of the mothers in the 29-33-week GA cohort and two of the women giving birth at 24-28-week GA.

RESULTS

Trend analysis showed that while cord plasma zinc decreased with GA at birth, the reverse was observed for copper. There were no differences with GA either in maternal plasma zinc or copper. However, maternal ceruloplasmin tended to decrease with GA (P=0.0174). Maternal and cord blood plasma magnesium exhibited a strong correlation (r=0.942, P<0.001), as well as between cord plasma magnesium and zinc (r=0.448, P<0.01).

CONCLUSIONS

While the vigorous mother-to-fetus uphill zinc transfer is clear throughout the last trimester, copper remains in cord blood plasma at much lower concentrations than in the mother, suggesting that prematurity may place the newborn infant at a greater risk than the term infant to copper deficiency. This situation, together with a reduced synthesis in the fetus of the transport protein ceruloplasmin, creates another potential challenge in the nutritional support of the premature infant.

Effect of gestational zinc deficiency on pregnancy outcomes: summary of observation studies and zinc supplementation trials

The lack of a valid indicator precludes a true estimate of zinc deficiency in pregnancy in various populations. However, it is possible that mild to moderate deficiency (as assessed by available indicators) may be common in the developing world. Animal experiments indicate that zinc deficiency can result in adverse maternal and fetal consequences. Human data, particularly from prenatal zinc supplementation trials, has failed to document a consistent maternal or infant benefit on evaluated outcome measures including pregnancy induced hypertension, preterm/post-term labour, premature rupture of membranes, maternal infection, postpartum haemorrhage, perinatal mortality, congenital malformations and fetal growth and gestation. Preliminary data suggest a beneficial effect of prenatal zinc supplementation on infants' neurobehavioural development and immune function (evaluated by diarrhoeal and ARI morbidity incidence in the first year of life). Future research should focus on these functional consequences and congenital malformations (with adequate sample sizes), and simultaneously address the safety issue, particularly in relation to micronutrient interactions. In the light of the currently available information, routine zinc supplementation can not be advocated to improve pregnancy outcome.

Maternal plasma zinc concentrations and pregnancy outcome

BACKGROUND

There is no consensus in the literature as to whether maternal zinc nutriture is associated with pregnancy outcome or fetal growth.

OBJECTIVE

We evaluated the associations between plasma zinc concentrations during pregnancy and various measures of pregnancy outcome and neonatal conditions at birth.

DESIGN

We measured zinc concentrations in plasma samples obtained at a mean of 16 wk of gestation (range: 6-34 wk) from 3448 women who were screened for a trial designed to evaluate the effect of zinc supplementation on fetal growth. Subjects were from low socioeconomic backgrounds and attended a public health clinic for their prenatal care. Plasma zinc concentrations were compared with pregnancy outcome, including complications during pregnancy and delivery, and anthropometric measures and Apgar scores of neonates.

RESULTS

Plasma zinc concentrations declined as gestation progressed. After plasma zinc concentrations were adjusted for gestational age, they were not significantly associated with any measure of pregnancy outcome or neonatal condition.

CONCLUSION

We conclude that plasma zinc concentrations during the late first trimester to the early third trimester do not predict pregnancy outcomes in women of a low socioeconomic background.

Factors influencing plasma zinc levels in low-income pregnant women

Plasma zinc (Zn) concentrations were measured in 4376 indigent women (86% African-American), at at mean (+/- SD) gestational age of 15 (+/- 7.8) wk to determine the relationship between various maternal characteristics and plasma Zn levels during pregnancy. Mean Plasma An levels were lower in African-American women than in Caucasian women, in multiparous women than in primiparous women, and in women with body weight > 69.9 kg than in those with body weight < or = 69.9 kg (p < or = 0.001 for each comparison). There were no significant differences related to maternal age, marital status, education, or smoking habit. Multiple regression analysis, including maternal prepregnancy weight, race, age, parity, smoking habit, education, and marital status indicated that race, parity, and pregnancy weight were significantly associated with maternal plasma Zn levels, adjusted for gestational age. Maternal race was the best predictor of plasma Zn concentrations among the population of pregnant women studied A significant proportion of variance in maternal plasma Zn levels. remained unexplained after taking into account various maternal characteristics. The reasons for lower plasma Zn levels in African-American women, compared to Caucasian women, during pregnancy are unknown.

Role of arsenic as a reproductive toxin with particular attention to neural tube defects

Arsenic has been recognized as a human toxicant for over 2000 years. More recently it has been readily accepted as a human carcinogen. Animal research has demonstrated arsenic's ability to have profound detrimental effects on the developing embryo in avian and mammalian species. This article comprehensively reviews the human and animal literature on the subject of the reproductive toxicity of arsenic. A variety of endpoints are considered, including spontaneous abortion, cardiovascular defects, and arsenic's role in the causation of neural tube defects (NTDs). A summary of the literature that has examined the various postulated mechanisms by which arsenic may produce NTDs is also considered. In addition, a discussion of literature relative to the presence of arsenic in the general environment and in the workplace is presented. This article reaches the conclusion that while further research is clearly needed, particularly on the potential toxicity of organic arsenical compounds, the current literature suggests it may be prudent and appropriate to treat inorganic arsenic as a probable human reproductive toxin.

Relationship between elevated lipid peroxides, vitamin E deficiency and hypertension in preeclampsia

Preeclampsia or pregnancy-induced hypertension is a major cause of both maternal and fetal-neonatal morbidity and mortality. The deficiency of vitamin E can cause accumulation of lipid peroxidation products, which, in turn, can induce vasoconstriction. This study has examined any evidence of increased cellular lipid peroxidation and accumulation of malonydialdehyde (MDA, an end product of lipid peroxidation) in pregnancy-induced hypertension and any relationship between the elevated MDA and lower vitamin E levels with hypertension in pregnant women. EDTA-Blood was collected from pregnant women at the time of delivery. Plasma vitamin E was determined by HPLC; MDA by the thiobarbituric acid-reactivity. Subjects with diastolic blood pressure (DBP) > or = 90 mm Hg were considered hypertensive (HT) and with < 90 mm Hg normotensive (NT). Data (Mean +/- SE) from 49 NT and 11 HT women show that HT has significantly lower vitamin E (22 +/- 1 vs 27 +/- 1 nmole/ml, p < 0.03) and elevated MDA levels (0.56 +/- 0.06 vs 0.43 +/- 0.02 nmole/ml, p < 0.03) compared to NT; the ages and gestational ages of women were similar. Among all women, there was a significant positive relationship between DBP and MDA levels (r = 0.27, p < 0.05), and a significant negative relationship between vitamin E levels and DBP (-0.36, p < 0.005), and a significant negative relationship between MDA and vitamin E levels (r = 0.27, p < 0.05). Thus, HT women's plasma has significantly lower E and higher MDA levels, and DBP significantly correlates with the extent of vitamin E deficiency and increased MDA levels. This study suggests a relationship between elevated lipid peroxidation and lower vitamin E levels and hypertension in pregnancy (preeclampsia).

Zinc, copper and selenium in reproduction

Of the nine biological trace elements, zinc, copper and selenium are important in reproduction in males and females. Zinc content is high in the adult testis, and the prostate has a higher concentration of zinc than any other organ of the body. Zinc deficiency first impairs angiotensin converting enzyme (ACE) activity, and this in turn leads to depletion of testosterone and inhibition of spermatogenesis. Defects in spermatozoa are frequently observed in the zinc-deficient rat. Zinc is thought to help to extend the functional life span of the ejaculated spermatozoa. Zinc deficiency in the female can lead to such problems as impaired synthesis/secretion of (FSH) and (LH), abnormal ovarian development, disruption of the estrous cycle, frequent abortion, a prolonged gestation period, teratogenicity, stillbirths, difficulty in parturition, pre-eclampsia, toxemia and low birth weights of infants. The level of testosterone in the male has been suggested to play a role in the severity of copper deficiency. Copper-deficient female rats are protected against mortality due to copper deficiency, and the protection has been suggested to be provided by estrogens, since estrogens alter the subcellular distribution of copper in the liver and increase plasma copper levels by inducing ceruloplasmin synthesis. The selenium content of male gonads increases during pubertal maturation. Selenium is localized in the mitochondrial capsule protein (MCP) of the midpiece. Maximal incorporation in MCP occurs at steps 7 and 12 of spermatogenesis and uptake decreases by step 15. Selenium deficiency in females results in infertility, abortions and retention of the placenta. The newborns from a selenium-deficient mother suffer from muscular weakness, but the concentration of selenium during pregnancy does not have any effect on the weight of the baby or length of pregnancy. The selenium requirements of a pregnant and lactating mother are increased as a result of selenium transport to the fetus via the placenta and to the infant via breast milk.

Altered maternal zinc metabolism following exposure to diverse developmental toxicants

It has been hypothesized that one mechanism contributing to the developmental toxicity of some xenobiotics is an embryonic/fetal zinc (Zn) deficiency that occurs secondary to toxicant-induced changes in maternal Zn metabolism. We studied the influence of diverse toxicants (urethane, ethanol, melphalan, arsenic, and alpha-hederin) on maternal-embryonic Zn metabolism and maternal liver metallothionein (MT) induction in Sprague-Dawley rats given a 65Zn-labelled meal by gavage 8 h after toxicant exposure and killed 10 h later on gestation day 12.5. Exposure to the toxicants resulted in increases in maternal hepatic MT concentrations that generally exceeded that which could be accounted for by reductions in food intake. 65Zinc retention was higher in maternal liver and lower in the products of conception in the toxicant-exposed groups. Strong linear relationships were found; as maternal liver MT concentrations increased, 65Zn retention in maternal liver was increased and 65Zn distribution to the conceptuses was decreased. These results support the hypothesis that diverse insults can produce developmental toxicity, in part, by altering maternal and embryonic Zn metabolism.

Hair zinc and dietary zinc intake during pregnancy and puerperium

A longitudinal study of hair zinc concentration was carried out in 36 pregnant women at 12 and 36 weeks of gestation and 40 days postpartum. A progressive decrease in hair zinc concentration was noted through pregnancy; the decline between 12 and 36 weeks of gestation was statistically significant (P < 0.005) remaining without significant changes in the postpartum. Nutrient intakes were calculated from 3-day weighed food records at the same periods and at 20 weeks of gestation. Zinc, energy and protein intakes decreased during pregnancy. Mean zinc intake at 20 and 36 weeks of gestation was about 66% of the recommended dietary allowance (RDA) (9.8 and 10 mg, respectively) and about 52% of the RDA in the postpartum (9.8 mg). Although hair zinc levels do decline in pregnancy and zinc intake was lower than RDA, the study revealed that zinc nutriture was adequate for normal growth and development of fetus.

The role of zinc in reproduction. Hormonal mechanisms

Zinc is a very important element in the reproductive cycle of species. In humans, it is necessary for the formation and maturation of spermatozoa, for ovulation, and for fertilization. During pregnancy, zinc deficiency causes a number of anomalies: spontaneous abortion, pregnancy-related toxemia, extended pregnancy or prematurity, malformations, and retarded growth. Delivery is adversely affected by deficiency. These different effects of zinc can be explained by its multiple action on the metabolism of androgen hormones, estrogen and progesterone, together with the prostaglandins. Nuclear receptors for steroids are all zinc finger proteins. Zinc supplementation has already proven beneficial in male sterility and in reducing complications during pregnancy. However, it would be worth conducting larger-scale trials to confirm these beneficial effects.

Effects of a multivitamin mineral supplement on zinc and copper status during pregnancy

The effect of a multivitamin-mineral supplement was investigated during pregnancy according to a double-blind protocol by determining zinc and copper in maternal plasma, mononuclear and polynuclear zinc and copper at the third, sixth, eighth, and ninth months of gestation. The subjects were supplemented from the first trimester until delivery. A significant decrease was observed in plasma zinc that varied from 11.5 mumol/L to 10.8 mumol/L in the supplemented group (n = 29) and from 11 mumol/L to 10 mumol/L in the placebo group (n = 33) at 3 and 9 mo of gestation, respectively. In contrast, plasma copper levels increased in a way depending upon the stage of gestation in both groups: from 24.7 to 28.2 mumol/L in the treated group and from 24.9 to 30.9 mumol/L in the placebo group at 3 and 9 mo of gestation, respectively, but the difference was only significant in the placebo group. No difference between groups was observed in mononuclear and polynuclear zinc or copper levels. These trace elements were also determined in cord blood at delivery. There were no statistically significant differences in zinc and copper concentration found in placebo group and supplemented group. Finally, the beneficial effect of supplementation on muscular cramps and appearance of vergetures was noted.

The relationship between maternal serum zinc levels during pregnancy and birthweight

A retrospective follow-up study to ascertain the relationship between the level of serum zinc and its rate of change during gestation and birthweight was conducted in 476 women of lower socioeconomic status. Serum zinc concentrations measured at approximately 16 (early) and 32 weeks (later) in gestation were both found to be significant predictors of birthweight. Even after controlling for gestational age at birth and other determinants of birthweight, for each microgram/dl increase in serum zinc early and later in pregnancy, birthweight increased by 5.8 and 8.6 g, respectively. Furthermore, after adjustment for initial zinc levels both the total change (beta = -7.0, P = 0.0007) and the rate of change (beta = -60.8, P = 0.007) in serum zinc during pregnancy were inversely associated with birthweight, i.e., the larger the fall in serum zinc during pregnancy, the smaller the infant. Low serum zinc level (less than 60 micrograms/dl) late in pregnancy was associated with greater than a five-fold increase in the odds (OR = 5.8, 95% CI = 1.8, 16.4) of giving birth to a low birthweight infant. The results of this study suggest a threshold for maternal serum zinc below which the prevalence of low birthweight increases rapidly.

The influence of dietary folate supplementation on the incidence of teratogenesis in zinc-deficient rats

Two studies were conducted to investigate the possibility that pteroylmonoglutamic acid supplementation would alleviate teratogenesis in zinc-deficient rats. Pregnant rats of the Wistar strain were fed on Zn-deficient (less than 0.5 mg Zn/kg) or Zn-supplemented (75 or 95 mg Zn/kg) diets from mating until day 18.5 of gestation. The basal level of pteroylmonoglutamic acid added to all diets (0.56 mg/kg) was supplemented with 30-200 mg/kg in selected diets. Dietary Zn deprivation resulted in fetal resorption, fetal growth retardation and reduced concentrations of Zn in fetuses and maternal plasma and tibia. Low maternal body-weight at conception emerged as an important determinant of risk of resorption in Zn-deficient rats. Dietary Zn deficiency resulted in reduced maternal plasma folate concentrations and these values were inversely correlated with litter size or weight in Zn-deficient rats. Pteroylmonoglutamic acid supplementation increased maternal plasma folate concentrations, but did not reduce the high incidence of teratogenesis which occurred in Zn-deficient rats. Supplementation of Zn-deficient rats with pteroylmonoglutamic acid significantly increased the incidence of clubbed foot and tended to increase the incidence of brain or meningeal abnormalities, or both, and cleft palate, but did not reduce maternal or fetal Zn status. Pteroylmonoglutamic acid supplementation also increased the weights of Zn-supplemented control fetuses.

Plasma and erythrocyte zinc and birth weight in pre-eclamptic pregnancies

Plasma and erythrocyte zinc concentrations in 45 proteinuric pre-eclamptic Chinese women were measured. There was no difference in either the plasma or erythrocyte zinc concentration between pre-eclamptic patients with and without intrauterine growth retardation. There was no correlation between either plasma or erythrocyte zinc concentration with the gestation at delivery, birth weight, mean arterial pressure and plasma albumin concentration. On the other hand, both plasma albumin concentration and mean arterial pressure were significantly correlated to birth weight, and the mean arterial pressure was also significantly higher in patients with intrauterine growth retardation. Plasma and erythrocyte zinc are not useful as indices of severity in pre-eclampsia.

[Preeclampsia: physiopathology and prospects for early detection]

Preeclampsia is a complication of pregnancy characterized by hypertension, edema and proteinuria, beginning after 20 weeks of gestation. Six percent of the pregnant women in North America develop this disease, which is associated with increased morbidity and mortality for the mother and her baby. The physiopathology remains uncertain despite many research efforts. Actual hypotheses seek to explain the vasospasm that characterizes the disease. Among the many factors influencing vascular reactivity and possibly implicated are: the renin-angiotensin system, prostaglandins, progesterone and its metabolites, calcium, magnesium, digoxin-like immunoreactive substance(s), auricular natriuretic factor, substances secreted by platelets and leukotrienes. Prevention of the disease is limited by the absence of a biological or clinical marker with good sensitivity and appropriate specificity. Many biochemical or hematological parameters have been reported: uric acid, calcium, magnesium, proteinuria, blood iron, hematocrit, platelet count, antithrombin III, estrogen and progesterone. The combination of several tests could be superior to the use of each test individually, providing a better sensitivity and improving the positive predictive value. With early detection, new therapies for the prevention of the disease could be experimented on the higher risk women before the apparition of clinical symptoms or signs. Furthermore, those tests could be used in the study of the pathophysiology and in the choice of the best therapy.

Zinc supplementation during pregnancy: a double blind randomised controlled trial

OBJECTIVE

To see whether zinc supplementation during pregnancy improves maternal and fetal outcome.

DESIGN

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.

SETTING

Mothers booking at one hospital.

PATIENTS

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.

INTERVENTIONS

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.

MAIN OUTCOME MEASURE

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.

RESULTS

There were no differences whatsoever between mothers given a zinc supplement and those given a placebo.

CONCLUSION

Zinc supplementation in pregnancy in the United Kingdom does not seem to offer any benefits to the mother or her fetus.

Zinc, cadmium, and hypertension in parturient women

Zinc deficiency and cadmium toxicity have both been implicated in hypertension during pregnancy. The goals of this study were twofold: first, to assess the different zinc indices (plasma, red blood cell zinc, heat-labile alkaline phosphatase, and placental zinc) in normotensive and hypertensive parturients to determine whether they are altered in the different types of hypertension that occur during pregnancy; second, to assess whole-blood cadmium and placental cadmium with regard to hypertension and zinc status. Patients were diagnosed as having chronic hypertension or preeclamptic toxemia and were then further divided into groups on the basis of smoking status. Each patient was matched with a normal control subject based on age, parity, and smoking status. Forty-three hypertensive patients and their matched control subjects were studied. No differences were found in the various zinc indices between chronic hypertensive parturients and normal control subjects. However, in parturients with preeclamptic toxemia, the plasma zinc level was 19% lower than in control subjects (p less than 0.02); these patients had the lowest plasma zinc level of the three groups. Placental zinc was also 12% lower in patients with preeclamptic toxemia than in control subjects (p less than 0.04). Whole-blood cadmium and placental cadmium levels did not differ between control subjects or hypertensive patients. However, a significant positive correlation was found between whole-blood cadmium and plasma zinc levels in preeclamptic toxemia (r = 0.53; p less than 0.05). The results support a marginal zinc deficiency in parturients with preeclamptic toxemia but not in those with chronic hypertension. The role of cadmium in the cause of preeclamptic toxemia remains unclear.

Plasma and erythrocyte zinc concentrations in pre-eclampsia

Plasma and erythrocyte zinc concentrations were measured in 28 Chinese pre-eclamptic women and 28 controls matched for parity, race and gestation. There were no differences in either the plasma or erythrocyte zinc concentrations between pre-eclamptic and control groups, although the mean birth weight (p less than 0.001) and period of gestation (p less than 0.001) at delivery in the control group were significantly higher. In the pre-eclamptic patients, those delivering before 37 weeks or those who gave birth to low birth weight (less than 2500 g), babies had a significantly higher plasma urate concentration (p less than 0.02) compared to the pre-eclamptic patients with better fetal outcome. However, the plasma and erythrocyte zinc concentrations between these subgroups were not significantly different. Our results suggest that zinc deficiency is unlikely to play a significant role in pre-eclampsia in our patients, and that measurement of plasma and erythrocyte zinc concentrations is of doubtful clinical value in the management of pre-eclampsia.

Serum zinc and copper concentrations in maternal and umbilical cord blood. Relation to course and outcome of pregnancy

Abnormal serum zinc and copper concentrations in pregnant women have been associated with a number of maternal and foetal complications during pregnancy and delivery. However, the results of previous studies are contradictory and few large scale studies have been reported. In this study we measured serum zinc and copper concentrations in maternal and umbilical cord blood from 500 Danish mothers at delivery, looking for an association between serum zinc and copper levels and various maternal and foetal complications. Preterm infants (n = 30) had significantly lower serum copper concentrations than reference infants (n = 346) (p = 0.01), whereas there was no difference in serum zinc concentrations. Mothers of preterm infants (n = 34) did not differ in serum zinc or copper concentrations from reference mothers (n = 220). Small for date infants (n = 37) and mothers of small for date infants (n = 47) had higher serum copper levels than reference infants and mothers (p = 0.02 and p = 0.04, respectively), whereas there was no difference in serum zinc concentrations. Serum zinc and copper concentrations in malformed infants (n = 14) and their mothers (n = 17) did not differ from concentrations in reference infants and mothers. Serum zinc and copper concentrations in mothers with various other complications during pregnancy and delivery did not differ from values in mothers with normal pregnancies and deliveries.