Complications of pregnancy in relation to maternal lipid peroxides, glutathione, and exposure to metals

Potential pathological mechanisms and pharmacological interventions for cadmium-induced miscarriage

The prevalence of cadmium (Cd) contamination has emerged as a significant global concern. Exposure to Cd during pregnancy is associated with adverse pregnancy outcomes, including miscarriage. However, there is currently a lack of comprehensive summaries on Cd-induced miscarriage. Therefore, it is imperative to further strengthen research into in vivo studies, clinical status, pathological mechanisms, and pharmacological interventions for Cd-induced miscarriage. This study systematically presents the current knowledge on animal models and clinical trials investigating Cd exposure-induced miscarriage. The underlying mechanisms involving oxidative stress, inflammation, endocrine disruption, and placental dysfunction caused by Cd-induced miscarriage are also extensively discussed. Additionally, potential drug interventions such as melatonin, vitamin C, and vitamin E are highlighted for their pharmacological role in mitigating adverse pregnancy outcomes induced by Cd.

Rolling back the gains: Maternal stress undermines pregnancy health after Flint's water switch

Environmental disasters impact disadvantaged communities disproportionately both through the epidemiological challenge of exposure, but also by undermining the progress of public health efforts. This paper studies changes to smoking cessation, breastfeeding, and weight gain during pregnancy in the period following the switch in water supply in Flint, Michigan, in April 2014. As the switch resulted in immediate and significant deterioration in water quality, eventually leading to its contamination with lead, we estimate a 10.5 percentage point increase in smoking and a 2.1 percentage point decrease in breastfeeding. We show evidence that these changes in maternal behavior are linked to increased stress due to changing water quality. We estimate that the increase in smoking alone is responsible for most of the increase in incidence of low birthweight among infants in Flint, resulting in $700 additional costs per birth. Increased smoking during pregnancy and lower breastfeeding rates in Flint roll back years of public health efforts, resulting in lifetime higher rates of cardiovascular disease, diabetes, and cancer for mothers in the community.

Peripheral Polymorphonuclear Leukocyte Priming Contributes to Oxidative Stress in Early Pregnancy

OBJECTIVE

The cause of elevated blood leukocyte count in pregnancy is unknown. We hypothesized that priming of peripheral polymorphonuclear leukocytes (PMNL) caused this elevation.

METHODS

Eleven women in the first trimester of pregnancy were included in this prospective study. Peripheral venous blood was drawn twice from each woman, before and after a medical abortion (pregnant and nonpregnant, respectively). Complete blood cell count, plasma alkaline phosphatase (ALP), and rate of superoxide release from separated phobrol 12-myristate-13-acetate (PMA)-stimulated PMNL were determined.

RESULTS

The PMNL count in early pregnancy was significantly higher, with a significant increase in the PMNL rate of superoxide release compared to the nonpregnant state. A linear correlation between the rates of superoxide release and PMNL counts before and during pregnancy was found. ALP levels were significantly elevated in early pregnancy.

CONCLUSION

The increased PMNL count is probably a compensatory response to PMNL priming. The increased rate of superoxide release from primed PMNL may contribute to oxidative stress in early pregnancy.

Appropriate Exposure Routes and Doses in Studies Designed to Assess Developmental Toxicity: A Case Study of Inorganic Arsenic

Assessment of risks to human health from chemical agents is a complex process that requires the assembly, careful analysis, and integration of human and animal data collected from studies performed at different times, for disparate purposes, and under varying conditions. The application of risk assessment methods to data without consideration of the relevance of critical experimental parameters such as route of exposure or magnitude of dose can lead to specious determinations of the risk posed by exposure to environmental agents. A case study of the purported risk of developmental toxicity from inorganic arsenic is presented to illustrate (1) the nature of the problem, (2) how extant data from all studies are useful, (3) how appropriately designed modern studies can clarify the situation, and (4) how conflicted data should be evaluated in terms of appropriateness for use in risk assessment.

A Proposed Molecular Mechanism of High-Dose Vitamin D3 Supplementation in Prevention and Treatment of Preeclampsia

A randomized prospective clinical study performed on a group of 74 pregnant women (43 presenting with severe preeclampsia) proved that urinary levels of 15-F(2t)-isoprostane were significantly higher in preeclamptic patients relative to the control (3.05 vs. 2.00 ng/mg creatinine). Surprisingly enough, plasma levels of 25-hydroxyvitamin D3 in both study groups were below the clinical reference range with no significant difference between the groups. In vitro study performed on isolated placental mitochondria and placental cell line showed that suicidal self-oxidation of cytochrome P450scc may lead to structural disintegration of heme, potentially contributing to enhancement of oxidative stress phenomena in the course of preeclampsia. As placental cytochrome P450scc pleiotropic activity is implicated in the metabolism of free radical mediated arachidonic acid derivatives as well as multiple Vitamin D3 hydroxylations and progesterone synthesis, we propose that Vitamin D3 might act as a competitive inhibitor of placental cytochrome P450scc preventing the production of lipid peroxides or excess progesterone synthesis, both of which may contribute to the etiopathogenesis of preeclampsia. The proposed molecular mechanism is in accord with the preliminary clinical observations on the surprisingly high efficacy of high-dose Vitamin D3 supplementation in prevention and treatment of preeclampsia.

Chinese herbal medicines for threatened miscarriage

BACKGROUND

Threatened miscarriage occurs in 10% to 15% of all pregnancies. Vaginal spotting or bleeding during early gestation is common, with nearly half of those pregnancies resulting in pregnancy loss. To date, there is no effective preventive treatment for threatened miscarriage. Chinese herbal medicines have been widely used in Asian countries for centuries and have become a popular alternative to Western medicines in recent years. Many studies claim to show that they can prevent miscarriage. However, there has been no systematic evaluation of the effectiveness of Chinese herbal medicines for threatened miscarriage.

OBJECTIVES

To review the therapeutic effects of Chinese herbal medicines for the treatment of threatened miscarriage.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2012), Chinese Biomedical Database (1978 to 31 January 2012), China Journal Net (1915 to 31 January 2012), China National Knowledge Infrastructure (1915 to 31 January 2012), WanFang Database (1980 to 31 January 2012), Chinese Clinical Trial Registry (31 January 2012), EMBASE (1980 to 31 January 2012), CINAHL (31 January 2012), PubMed (1980 to 31 January 2012), Wiley InterScience (1966 to 31 January 2012), International Clinical Trials Registry Platform (31 January 2012) and reference lists of retrieved studies. We also contacted organisations, individual experts working in the field, and medicinal herb manufacturers.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared Chinese herbal medicines (alone or combined with other pharmaceuticals) with placebo, no treatment (including bed rest), or other pharmaceuticals as treatments for threatened miscarriage.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all the studies for inclusion in the review, assessed risk of bias and extracted the data. Data were checked for accuracy.

MAIN RESULTS

In total, we included 44 randomised clinical trials with 5100 participants in the review.We did not identify any trials which used placebo or no treatment (including bed rest) as a control.The rate of effectiveness (continuation of pregnancy after 28 weeks of gestation) was not significantly different between the Chinese herbal medicines alone group compared with the group of women receiving Western medicines alone (average risk ratio (RR) 1.23; 95% confidence interval (CI) 0.96 to 1.57; one trial, 60 women).Chinese herbal medicines combined with Western medicines were more effective than Western medicines alone to continue the pregnancy beyond 28 weeks of gestation (average RR 1.28; 95% CI 1.18 to 1.38; five trials, 550 women).

AUTHORS' CONCLUSIONS

There was insufficient evidence to assess the effectiveness of Chinese herbal medicines alone for treating threatened miscarriage.A combination of Chinese herbal and Western medicines was more effective than Western medicines alone for treating threatened miscarriage. However, the quality of the included studies was poor. More high quality studies are necessary to further evaluate the effectiveness of Chinese herbal medicines for threatened miscarriage.

Mushroom lectin protects arsenic induced apoptosis in hepatocytes of rodents

Acute and chronic arsenic exposure result in toxicity both in human and animal beings and cause many hepatic and renal manifestations. The present study stated that mushroom lectin prevents arsenic-induced apoptosis. Apoptosis was measured by morphological alterations, cell proliferation index (CPI), phagocytic activity (nitro blue tetrazolium index; NBT), nitric oxide (NO) production, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, DNA fragmentation and caspase-3 activity. Arsenic exposure at 5 μM in the form of sodium arsenite resulted in significant elevation of deformed cells, NO production, TUNEL stained nuclei of hepatocytes, DNA fragmentation and caspase-3 activity. But the CPI and NBT index were significantly declined in arsenic-treated hepatocytes. The beneficial effect of mushroom lectin at 10 μg/mL, 20 μg/mL and 50 μg/mL) showed increased CPI and phagocytic activity. Mushroom lectin at those concentrations reduced deformed cells, NO production, DNA fragmentation and caspase-3 activity of hepatocytes. But significant better protection was observed in 50 μg/mL mushroom lectin-treated hepatocytes. This finding may be of therapeutic benefit in people suffering from chronic arsenic exposure.

Short-term exposure of female rats to industrial metal salts: Effect on implantation and pregnancy

Aim: The objective of this study was to characterize the adverse effects of industrial metal salts during the early stages of pregnancy. Methods: Successfully mated female rats were exposed to the following metal salts via intragastric intubation; manganese sulfate, lead acetate, aluminum chloride, ferrous chloride and ferric chloride in doses of 50 mg/kg body weight and chromium chloride and potassium dichromate in doses of 25 mg/kg body weight on days l-3 or 4-6 of pregnancy. Female rats were killed on day 20 of gestation and the pregnancy outcome was determined. Results: The administration of manganese sulfate, chromium chloride, potassium dichromate and ferric chloride to female rats on days 1-3 of pregnancy caused pregnancy failure. However, the administration of manganese sulfate and potassium dichromate reduced the number of implantations. The administration of manganese sulfate, potassium dichromate and ferric chloride reduced the number of viable fetuses. The total number of resorptions increased in the lead acetate, aluminum chloride, ferrous chloride and ferric chloride exposed groups. In contrast, the administration of manganese sulfate, aluminum chloride and ferric chloride on days 4-6 of pregnancy caused pregnancy failure. However, the administration of ferric chloride reduced the number of implantations. The administration of manganese sulfate, aluminum chloride, potassium dichromate, ferrous chloride and ferric chloride reduced the number of viable fetuses. The total number of resorptions increased in the manganese sulfate, lead acetate, aluminum chloride, potassium dichromate, ferrous chloride and ferric chloride exposed groups. Conclusion: This work demonstrates that the short-term exposure of female rats to industrial metal salts during the early stages of gestation would cause failure of pregnancy and produce fetotoxic or fetal resorptive potentials. (Reprod Med Biol 2007; 6: 179-183).

Arsenic exposure from drinking water and birth weight

BACKGROUND

Arsenic exposures from drinking water increase the risk of various cancers and noncancer health endpoints. Limited evidence suggests that arsenic may have adverse human reproductive effects. We investigated the association between drinking water arsenic exposure and fetal growth, as manifest in birth weight.

METHODS

We conducted a prospective cohort study in two Chilean cities with contrasting drinking water arsenic levels: Antofagasta (40 micro g/L) and Valparaíso (<1 micro g/L). Study subjects completed in-depth interviews and provided urine samples for exposure analysis. We obtained pregnancy and birth information from medical records. The birth weight analysis was restricted to liveborn, singleton infants born between December 1998 and February 2000.

RESULTS

The final study group consisted of 424 infants from Antofagasta and 420 from Valparaíso. After controlling for confounders, results of the multivariable analysis indicated that Antofagasta infants had lower mean birth weight (-57 g; 95% confidence interval = -123 to 9).

CONCLUSION

This study suggests that moderate arsenic exposures from drinking water (<50 micro g/L) during pregnancy are associated with reduction in birth weight, similar in magnitude to that resulting from other environmental exposures such as environmental tobacco smoke and benzene.

Causes of oxidative stress in the pre- and perinatal period

Oxidative stress may be defined as an imbalance between pro-oxidant and antioxidant forces resulting in an overall pro-oxidant insult. Pregnancy is a physiological state accompanied by a high energy demand of many bodily functions and an increased oxygen requirement. Because of the increased intake and utilization of oxygen, augmented levels of oxidative stress would be expected. Arguments for a role of oxidative stress/oxidative lipid derivatives in the pathogenesis of preeclampsia are documented in many papers and evidence continues to accumulate that oxidative stress is a mediator of endothelial dysfunction and thus contributes to the cardiovascular complications of preeclampsia. Also other conditions, such as toxic substance exposure, smoking and asphyxia likewise induce oxidative stress. The oxidized lipid products generated as a consequence of these conditions are highly reactive and cause damage to cells and cell membranes. Thus, increased oxidative stress accompanied by reduced endogenous defences may play a role in the pathogenesis of a number of diseases in the newborn.

Effects of maternal exposure to cadmium on pregnancy outcome and breast milk

OBJECTIVE

The effects of cadmium (Cd) on birth weight have been discussed in the scientific literature. However, investigations on the effects of maternal body burden of Cd on the next generation during pregnancy and lactation have been limited. The relation between maternal exposure to Cd and pregnancy outcome or Cd in breast milk in Japanese mothers was investigated.

METHODS

Cd concentrations in urine and colostrum milk samples of 57 mothers were measured by atomic absorption spectrophotometery. The relations between maternal urinary Cd and infant growth, gestational age at birth, and Cd in breast milk were investigated.

RESULTS

The rate of perterm deliveries of mothers with higher urinary Cd (> or =2 nmol/mmol creatinine (Cr)) was higher than that of mothers with lower urinary Cd (<2 nmol/mmol Cr). The gestational age was significantly correlated with urinary Cd even after adjustment for maternal age. The height and weight of newborn infants of mothers with higher urinary Cd were significantly lower than those of the newborn infants of mothers with lower urinary Cd, but these decreases were ascribed to early delivery induced by Cd. The Cd in breast milk of mothers with higher urinary Cd was significantly higher than that of mothers with lower urinary Cd. A significant positive correlation was found between maternal urinary Cd and Cd in breast milk.

CONCLUSION

Maternal exposure to Cd seems to increase early delivery, which leads to a lower birth weight. Also, the Cd is transferred in part to the next generation through breast milk after birth.

Occupational and environmental risks of spontaneous abortions around a smelter

BACKGROUND

This study represents part of a follow-up study on reproductive outcome around a smelter in Sweden.

METHODS

Employees at the smelter, a random sample including neighbors of the smelter and referents were analyzed by a register study, covering 1982-1990, a questionnaire study performed in 1992 and a case-referent study with cases of spontaneous abortions and live borns as referents. Risk factors were studied by logistic regression. A validity-study between register and questionnaire data on spontaneous abortions and legal abortions was completed.

RESULTS

The studies showed no risk increase for the exposed groups of smelter workers and neighbors compared to the reference group, 10, 11, and 12%, respectively. A validation of the data on abortions between register and questionnaire data showed good agreement.

CONCLUSIONS

We found no increase of spontaneous abortion associated to smelter work or to living close to the smelter which could be a result of radically reduced emissions.

Teratogen update: inorganic arsenic

BACKGROUND

Inorganic arsenic has been used by many laboratories to study the pathogenesis of exencephaly in rodents. These studies, which used predominantly injection exposures, coupled with the paucity of epidemiology data, resulted in the erroneous inference that inorganic arsenic should be considered a human teratogen.

METHODS

This study assembles and assesses literature analyses of older human and animal investigations together with the results of new experimental studies. These recent studies were performed according to modern regulatory guidelines, and relevant exposure routes (inhalation and ingestion) were used to evaluate the potential risk of developmental effects in humans.

RESULTS

The existing epidemiological data are inadequate to support risk assessment because of the failure to confirm or measure arsenic exposure during early gestation and the deficiencies in accounting for potential confounding factors. The animal data revealed that inorganic arsenic caused malformations in offspring only when it was injected into the veins or peritoneal cavity of pregnant animals during early gestation. Exposure via inhalation or oral ingestion, even at concentrations that were nearly fatal to pregnant females, caused no arsenic-related malformations.

CONCLUSIONS

Inorganic arsenic poses virtually no danger to developing offspring when maternal exposure occurs by relevant routes (oral and inhalation) at concentrations that are likely to be experienced in the environment or in the workplace.

Changes in maternal lipid peroxidation levels and antioxidant enzymatic activities before and after delivery

OBJECTIVE

Our goal was to characterize the changes in maternal lipid peroxidation levels and antioxidant enzymatic activities before and after delivery.

METHODS

Predelivery and 1, 24, and 48 hours post-partum plasma concentrations of malondialdehyde, erythrocyte enzyme superoxide dismutase, glutathione peroxidase and catalase were measured in uncomplicated pregnancies.

RESULTS

Malondialdehyde levels increased slightly from predelivery to 24 hours post-partum and then decreased significantly at 48 hours post-partum. At one hour post-partum superoxide dismutase and catalase levels increased significantly to about 125% and 170% of predelivery levels, respectively. Thereafter, these values decreased significantly from one hour to 48 hours post-partum. The relative changes in superoxide dismutase and catalase levels at one hour post-partum compared to predelivery values correlated significantly with the duration of labor.

CONCLUSION

The results suggest that the uncontrolled lipid peroxidation caused by reactive oxygen species, which are produced in consequence of tissue reoxygenation, may occur during labor and that prolonged labor, may cause maternal oxidative stress.

Appropriate use of animal models in the assessment of risk during prenatal development: an illustration using inorganic arsenic

BACKGROUND

Assessing risks to human development from chemical exposure typically requires integrating findings from laboratory animal and human studies.

METHODS

Using a case study approach, we present a program designed to assess the risk of the occurrence of malformations from inorganic arsenic exposure. We discuss how epidemiological data should be evaluated for quality and criteria for determining whether an association is causal. In this case study, adequate epidemiological data were not available for evaluating the potential effect of arsenic on development. Consequently, results from appropriately designed, conducted, and interpreted developmental toxicity studies, which have been shown to be predictive of human risk under numerous scenarios, were used. In our case study, the existing animal data were not designed appropriately to assess risk from environmental exposures, although such studies may be useful for hazard identification. Because the human and animal databases were deficient, a research program comprising modern guideline toxicological studies was designed and conducted.

RESULTS

The results of those studies in rats, mice, and rabbits indicate that oral and inhalational exposures to inorganic arsenic do not cause structural malformations, and inhalational exposures produced no developmental effects at all. The new study results are discussed in conjunction with considerations of metabolism, toxicokinetics, and maternal toxicity.

CONCLUSIONS

Based on the available experimental data, and absent contrary findings from adequately conducted epidemiological studies, we conclude that exposure to inorganic arsenic by environmentally relevant routes poses no risk of the occurrence of malformations and little risk of other prenatal developmental toxicity in developing humans without concomitant and near-lethal toxicological effects in mothers.

Effect of lead on erythrocytic antioxidant defence, lipid peroxide level and thiol groups in calves

Fifteen crossbred male calves were exposed to lead for a period of 28 days orally at the dose rate of 7.5 mg of lead acetate as 0.75 per cent solution kg(-1)body weight to study its effect on erythrocytic antioxidant defense, lipid peroxide level and thiol groups. Five calves were given no treatment and served as unexposed controls. Blood samples were collected before exposure to lead and thereafter at weekly intervals (ie. on day 7, 14, 21 and 28). Erythrocyte haemolysate (10 per cent) was prepared and analysed for lipid peroxide level, activity of Superoxide dismutase (SOD) and catalase. Total, protein-bound and non protein-bound thiol groups were also measured. Exposure to lead significantly (P < 0.05) reduced the erythrocytic SOD activity by day 7 and it remained lower until day 21 followed by a marginal increase on day 28. Catalase activity declined after an initial compensatory rise on day 7. Erythrocytic lipid peroxide level was recorded to be significantly (P < 0.05) higher by day 21 and 28 of exposure. Total, protein-bound and non protein-bound -SH content of erythrocytes declined. It was concluded that oral exposure of lead reduced the erythrocytic thiol content and antioxidant defence indicating possible role of free radicals in pathogenesis of lead toxicity.

Levels of lipid peroxides in uncomplicated pregnancy: a review of the literature

The literature on lipid peroxide levels in uncomplicated pregnancy is limited, but some reasonable conclusions are possible. Despite the lack of precision in the predominant measure of lipid oxidation, there is agreement across a large number of studies that the level of lipid peroxides in blood is generally higher in pregnant women than in nonpregnant women. During gestation, elevations appear by the second trimester and may taper off later in gestation, decreasing further after delivery. Lipid peroxides also are produced in placenta, but their pattern of change over the course of pregnancy is unclear. Lipid peroxides are important because their uncontrolled production can result in oxidative stress, with significant damage to cell integrity. There is a growing literature that associates oxidative stress with preeclampsia, a major cause of maternal and fetal morbidity. The higher levels of lipid peroxides seen in blood and the production of lipid peroxides in the placenta, even in uncomplicated pregnancies, make new baseline studies a priority. These studies should include measurements of lipids and blood volume, because they can influence marker values, with sensitive and specific measures of lipid peroxidation made at various points of gestation. From our review of the existing literature we conclude that the importance of oxidative stress in reproduction is just beginning to be appreciated and studied.

Post-invasion change in the trend of complications and outcome of pregnancy in Maternity Hospital Kuwait from 1981 to 1995

To assess the trend in the complications and outcome of pregnancy in Maternity Hospital, Kuwait, a retrospective analysis of yearly hospital statistics books and labour ward records of patients delivering in Maternity Hospital Kuwait was carried out for the period 1981 to 1995. In the post-invasion period there is a significant rise in: primiparity; mothers aged 35 years or older; Kuwaiti mothers; and in multiple pregnancy. The incidence of pregnancy-induced hypertension, pre-eclampsia, and hysterectomy for postpartum haemorrhage also increased. There was a significant increase in spontaneous abortions and low birth weight babies. The incidence of hydatidiform mole has significantly decreased. Still birth rate shows a decreasing trend in the study period. The significant change in the age and parity of the mothers delivering in the post-invasion period might partly explain the above changes. However, the effect of environmental pollution, social and psychological stress, and anxiety due to war may have also contributed to an increase in the complications and adverse outcomes of pregnancy.

An assessment of the developmental toxicity of inorganic arsenic

A critical analysis of the literature base regarding the reproductive and developmental toxicity of arsenic compounds, with emphasis on inorganic arsenicals, was conducted. The analysis was stimulated by the great number of papers that have purported to have shown an association between exposure of pregnant laboratory animals to arsenic compounds and the occurrence of offspring with cranial neural tube defects, particularly exencephaly. For the most part, the literature reports of arsenic developmental toxicity in experimental animals are inadequate for human risk assessment purposes. Despite the shortcomings of the experimental database, several conclusions are readily apparent when the animal studies are viewed collectively. First, cranial neural tube defects are induced in rodents only when arsenic exposure has occurred early in gestation (on Days 7 [hamster, mouse], 8 [mouse], or 9 [rat]). Second, arsenic exposures that cause cranial neural tube defects are single doses that are so high as to be lethal (or nearly so) to the pregnant animal. Third, the effective routes of exposure are by injection directly into the venous system or the peritoneal cavity; even massive oral exposures do not cause increases in the incidence of total gross malformations. Fourth, repetition of similar study designs employing exaggerated parenteral doses is the source of the large number of papers reporting neural tube defects associated with prenatal arsenic exposure. Fifth, in five repeated dose studies carried out following EPA Guidelines for assessing developmental toxicity, arsenic was not teratogenic in rats (AsIII, 101 micromol/kg/d, oral gavage; 101 micromol/m3, inhalation), mice (AsV, 338 micromol/kg/d, oral gavage; est. 402 micromol/kg/d, diet), or rabbits (AsV, 21 micromol/kg/d, oral gavage). Data regarding arsenic exposure and adverse outcomes of pregnancy in humans are limited to several ecologic epidemiology studies of drinking water, airborne dusts, and smelter environs. These studies failed to (1) obtain accurate measurements of maternal exposure during the critical period of organogenesis and (2) control for recognized confounders. The lone study that examined maternal arsenic exposure during pregnancy and the presence of neural tube defects in progeny failed to confirm a relationship between the two. It is concluded that under environmentally relevant exposure scenarios (e.g., 100 ppm in soil), inorganic arsenic is unlikely to pose a risk to pregnant women and their offspring.

Peroxidative and glutathione status in uterus and placenta after normal and pathological pregnancy

In 10 women with disturbed pregnancies without hypertension, reduced (GSH) and oxidized glutathione (GSSG) as well as lipid peroxides as thiobarbituric acid reactive substances (TBARS) were determined in the placenta and in the uterine tissue after unexpected stress-induced Caesarian section (group II). Production of TBARS was also measured in vitro in the 9000 x g supernatant of both tissues. The results were compared with those from women after normal pregnancy and expected Caesarian section (group I). After normal pregnancy higher TBARS and lower GSH with higher GSSG/GSH ratio were found in the placenta in comparison to the uterine tissue, indicating an oxidant/antioxidant imbalance in the placenta. No statistically significant differences were shown between the parameters of groups I and II. The possible oxidant stress associated with disturbed pregnancy and subsequent unexpected Caesarian section in this study was insufficient to alter tissue levels of glutathione nor the peroxidative status of placenta and uterus.

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.