Spontaneous abortion in spouses of greenhouse workers exposed to pesticides

Pesticide exposure and spontaneous abortion risk: A comprehensive systematic review and meta-analysis

BACKGROUNDS AND AIM

Exposure to pesticides has been proposed as a potential contributor to adverse pregnancy outcomes, possibly through the induction of inflammation, oxidative stress, and disruption of endocrine functions. Nevertheless, the definitive link between prenatal pesticide exposure and the risk of Spontaneous Abortion (SAB) remains uncertain. The objective of this systematic review is to explore and analyze the existing evidence regarding the link between pesticide exposure and the risk of SAB.

METHODS

A comprehensive systematic literature search was carried out on PubMed, Web of Science, and Scopus from their inception until February 2024 to identify relevant studies exploring the potential link between pesticide exposure and SAB. The frequency of SAB events and the total number of patients in each group were used to calculate the Relative Risk (RR) using the Mantel-Haenszel random-effects model. Heterogeneity among the studies was evaluated by visually inspecting the forest plot and performing the Chi-square test and I2 tests. We also used RevMan version 5.4 for Windows for the analysis. We also used the NIH tool to assess the quality of the included studies.

RESULTS

The initial database search yielded 2121 results, with 1525 articles remaining after removing duplicates. After screening, 29 articles were eligible for full-text review, and 18 studies (Four case-control, eleven cohorts, three cross-sectional) were included in the meta-analysis, comprising 439,097 participants. All included studies evaluated the primary outcome, SAB. Most of the included studies were cross-sectional in design, and pesticide exposure was primarily assessed through questionnaires administered to patients. We found that most of our observational studies, precisely 12 out of the total, were deemed fair quality. Four studies were rated poor quality, while only two received a good quality rating. The analysis demonstrated a significant 41 % increase in SAB risk among pregnant women exposed to pesticides compared to pregnant women without exposure to pesticides (RR= 1.41, 95 % CI; [1.10, 1.80], P= 0.006).

CONCLUSION

Our systematic review and meta-analysis revealed a significant 41 % increase in the risk of SAB among pregnant women exposed to pesticides. However, it is essential to acknowledge the limitations of the current evidence: potential publication bias and the inability to establish causality. Moving forward, future research should focus on longitudinal studies, mechanistic insights, and risk reduction strategies. In summary, our findings underscore the urgency of public health measures to protect maternal and fetal health in pesticide-exposed areas. Rigorous research and preventive strategies are crucial to mitigate adverse outcomes.

Effects of commonly used carbamates (carbaryl and thiram) on the regulatory, secretory and motor functions of bovine cervixes in vitro

Previously studied classes of pesticides, including organochlorines, organophosphates and pyrethroids disturb the mechanism that causes bovine myometrial contractions. Hence, the aim of this study was to investigate the effects of carbaryl and thiram, which are representative carbamate pesticides commonly used in global agriculture, on the motor and secretory functions of bovine cervixes. Additionally, the impacts of these pesticides on intra- and intercellular signaling in vitro were estimated. In this study, cervical cells or strips were obtained from cows at days 18-20 of the estrous cycle and were treated with carbaryl or thiram. Neither carbamate (10 or 100 ng/ml) exerted cytotoxic effects. Carbaryl increased the level of mRNA (at a dose of 0.1 ng/ml) and protein (at both doses, 1 and 10 ng/ml) expression for the oxytocin receptor (OXTR), while thiram (at 0.1 and 10 ng/ml or 0.1-10 ng/ml, respectively) caused the opposite effects. Moreover, the level of the second messenger inositol-trisphosphate (IP3) was decreased by carbaryl (10 ng/ml) but increased by thiram (10 ng/ml). Only thiram decreased prostaglandin-endoperoxide synthase 2 (PTGS2; 0.1 ng/ml) and aldo-keto reductase family 1, member B1 (AKR1B1; 0.1 ng/ml), and prostaglandin E synthase 2 (PTGES2; 0.1-10 ng/ml) mRNA expression, while thiram (0.1-10 ng/ml) and carbaryl (0.1 and 10 ng/ml) both decreased the release of PGF2α. Carbaryl (10 ng/ml) and thiram (10 ng/ml) also decreased the level of a gap junction protein (GAP). Moreover, carbaryl (10 ng/ml) decreased the level of myosin light chain kinase (MLCK). However, the strength of cervical contractions was increased by thiram (1 and 10 ng/ml) but decreased by carbaryl (1 and 10 ng/ml). Carbaryl increased the receptivity of cervical cells to oxytocin (OXT), but inhibited further transduction (IP3) of this signal. Hence, direct inhibition of cervical strip contraction may occur. In contrast, thiram mostly decreased the receptivity of cervical cells to OXT, while it stimulated the contraction of cervical strips. Moreover, compared to carbaryl, thiram more greatly affected the synthesis and release of prostaglandins. These results suggest that carbaryl and thiram disturb OXT signaling, PG secretion and cervical contraction in vitro.

The Silent Threat to Women's Fertility: Uncovering the Devastating Effects of Oxidative Stress

Oxidative stress (OS), which arises through an imbalance between the formation of reactive oxygen species (ROS) and antioxidant defenses, plays a key role in the pathophysiology of female infertility, with the latter constituting just one of a number of diseases linked to OS as a potential cause. The aim of the present article is to review the literature regarding the association between OS and female infertility. Among the reproductive diseases considered are endometriosis and polycystic ovary syndrome (PCOS), while environmental pollutants, lifestyle variables, and underlying medical conditions possibly resulting in OS are additionally examined. Current evidence points to OS likely contributing to the pathophysiology of the above reproductive disorders, with the amount of damage done by OS being influenced by such variables as duration and severity of exposure and the individual's age and genetic predisposition. Also discussed are the processes via which OS may affect female fertility, these including DNA damage and mitochondrial dysfunction. Finally, the last section of the manuscript contains an evaluation of treatment options, including antioxidants and lifestyle modification, capable of minimizing OS in infertile women. The prime message underlined by this review is the importance of considering OS in the diagnosis and treatment of female infertility. Further studies are, nevertheless required to identify the best treatment regimen and its ideal duration.

Sperm abnormality and infertility in male mice treated with the recommended dose of dimethoate and its double

Background

Dimethoate (DM) is one of the most important organophosphate insecticides used for controlling many pests which affect vegetables, fruits, and agricultural crops, its persistence in soils and crops could cause a health hazard to humans as well as other non-target organisms.

Aim

This study was conducted to evaluate the effect of the recommended dose and its double of DM on sex hormones, sperm morphology, and fertility of adult male mice.

Methods

Twenty-seven Swiss albino adult male mice were divided into three groups of nine animals each: control group received distilled water only, while other groups received DM orally at doses (0.1 and 0.2 ml DM/100 ml distilled water) for 20 days, at the end of the treatment, six mice from each group were sacrificed. The sperm morphology was evaluated and sex hormones were measured. Three mice from each group were allowed to mate with untreated females (1:2).

Result

The results revealed a decrease in luteinizing hormone levels in mice treated with (0.2 ml DM/100 ml distilled water) compared with the control group while the levels of follicle-stimulating hormone and testosterone did not record any significant differences. Also, the results demonstrated a significant increase in abnormal sperm morphology such as head and tail. The fertility was reduced and the average number of dead embryos increased while the average number of live embryos decreased.

Conclusion

This current study confirmed that DM has detrimental effects on sperm morphology, fertility, and the embryos; therefore, more efforts should be exerted to protect ourselves and our environment from the harmful effects of this pesticide.

Exposure to Atrazine through gestation and lactation period led to impaired sexual maturation and subfertility in F1 male rats with congenital deformities in F2 progeny

Several scientific reports suggest perturbed reproductive and developmental defects associated with environmental exposure to Atrazine (ATR). ATR has been associated with altered endocrine and reproductive functioning in-vivo exposed during the critical window of development. Thus, the present study investigates the effect of ATR exposure on F1-F2 male progeny exposed through gestation and lactation. F0 dams administered with ATR at doses 2, 10, 70, and 100 mg/kg b. wt/day from gestation day 6 to postnatal day 21. The F1 male rats were monitored for sexual maturation and subjected to fertility assessment on PND75. Delayed testicular descent was observed in 10, 70, and 100 mg/kg b. wt/day ATR dose with significantly lower serum testosterone, sperm count, and motility with testicular defects in F1 male. Expression of Androgen receptor (AR), Estrogen receptors (ER α and ER β), StAR, Aromatase, and INSL-3 were upregulated at all doses indicating estrogenic/anti-androgenic activity of ATR. Fertility assessment revealed subfertility in F1 males with high (%) pre- and post-implantation loss at 10, 70, and 100 mg/kg b. wt/day dose as compared to control. Further, F2 fetuses exhibited congenital disabilities viz. decreased weight, crown-rump length, and anogenital distance with several other morphological deformities. To conclude, ATR exerted estrogenic and/or anti-androgenic activity with fetotoxic effects through the male germline.

Determinants of Skin and Respiratory Exposure to Lufenuron During Spraying and Re-entry in Italian Ornamental Plants Greenhouses

The aim of this study was to evaluate dermal and respiratory exposure of workers to Lufenuron during spraying and re-entry on ornamental plants (stapling) in greenhouses. Potential and real skin exposure were evaluated using filter paper pads, hand contamination by washing, and respiratory exposure by personal air sampling. Dislodgeable foliar residues (DFRs) during re-entry were determined in order to calculate the dermal transfer factor (DTF). Lufenuron was analysed by liquid chromatography-mass detection. Respiratory dose (ReD) was calculated on the basis of a lung ventilation of 15-20 l min-1 and absorbed doses assuming a skin penetration of 13% and a respiratory retention of 100%. During stapling, from the dependence of exposure of hands from DFRs, the mean DTF was 0.575 cm2 h-1 (geometric mean). The ReD was 68.7-74.6 and 0.022-0.636% of the total real dose during spraying and stapling, respectively. The absorbed doses, 0.144-0.171 and 0.005-0.124 µg kg bw-1 during spraying and stapling, respectively, were less than the acceptable operator exposure level of 10 µg kg bw-1. Proper use of equipment and personal protective equipment and personal hygiene are aspects of fundamental importance on which workers must be trained. Adequate occupational hygiene studies are needed to support and verify working practices.

In vitro effects of the endocrine disruptor p,p'DDT on human choriogonadotropin/luteinizing hormone receptor signalling

Dichlorodiphenyltrichloroethane (p,p'DDT) is an endocrine-disrupting chemical (EDC). Several studies showed an association between p,p'DDT exposure and reprotoxic effects. We showed that p,p'DDT was a positive allosteric modulator of human follitropin receptor (FSHR). In contrast, we demonstrated that p,p'DDT decreased the cyclic AMP (cAMP) production induced by human choriogonadotropin (hCG). This study evaluated further the effects of p,p'DDT on Gs-, β-arrestin 2- and steroidogenesis pathways induced by hCG or luteinizing hormone (LH). We used Chinese hamster ovary cells line stably expressing hCG/LHR. The effects of 10-100 µM p,p'DDT on cAMP production and on β-arrestin 2 recruitment were measured using bioluminescence and time-resolved resonance energy transfer technology. The impact of 100 µM of p,p'DDT on steroid secretion was analysed in murine Leydig tumor cell line (mLTC-1). In cAMP assays, 100 µM p,p'DDT increased the EC₅₀ by more than 300% and reduced the maximum response of the hCG/LHR to hCG and hLH by 30%. This inhibitory effect was also found in human granulosa cells line and in mLTC-1 cells. Likewise, 100 µM p,p'DDT decreased the hCG- and hLH-promoted β-arrestin 2 recruitment down to 14.2 and 26.6%, respectively. Moreover, 100 µM p,p'DDT decreased by 30 and 47% the progesterone secretion induced by hCG or hLH, respectively, without affecting testosterone secretion. This negative effect of p,p'DDT was independent of cytotoxicity. p,p'DDT acted as a negative allosteric modulator of the hCG/LHR signalling. This emphasizes the importance of analyzing all receptor-downstream pathways to fully understand the deleterious effects of EDC on human health.

Identification of environmental chemicals targeting miscarriage genes and pathways using the comparative toxicogenomics database

BACKGROUND

Miscarriage is a prevalent public health issue and many events occur before women are aware of their pregnancy, complicating research design. Thus, risk factors for miscarriage are critically understudied. Our goal was to identify environmental chemicals with a high number of interactions with miscarriage genes, based on known toxicogenomic responses.

METHODS

We used miscarriage (MeSH: D000022) and chemical gene lists from the Comparative Toxicogenomics Database in human, mouse, and rat. We assessed enrichment for gene ontology biological processes among the miscarriage genes. We prioritized chemicals (n = 25) found at Superfund sites or in the blood or urine pregnant women. For chemical-disease gene sets of sufficient size (n = 13 chemicals, n = 20 comparisons), chi-squared enrichment tests and proportional reporting ratios (PRR) were calculated. We cross-validated enrichment results.

RESULTS

Miscarriage was annotated with 121 genes and overrepresented in inflammatory response (q = 0.001), collagen metabolic process (q = 1 × 10-13), cell death (q = 0.02), and vasculature development (q = 0.005) pathways. The number of unique genes annotated to a chemical ranged from 2 (bromacil) to 5607 (atrazine). In humans, all chemicals tested were highly enriched for miscarriage gene overlap (all p < 0.001; parathion PRR = 7, cadmium PRR = 6.5, lead PRR = 3.9, arsenic PRR = 3.5, atrazine PRR = 2.8). In mice, highest enrichment (p < 0.001) was observed for naphthalene (PRR = 16.1), cadmium (PRR = 12.8), arsenic (PRR = 11.6), and carbon tetrachloride (PRR = 7.7). In rats, we observed highest enrichment (p < 0.001) for cadmium (PRR = 8.7), carbon tetrachloride (PRR = 8.3), and dieldrin (PRR = 5.3). Our findings were robust to 1000 permutations each of variable gene set sizes.

CONCLUSION

We observed chemical gene sets (parathion, cadmium, naphthalene, carbon tetrachloride, arsenic, lead, dieldrin, and atrazine) were highly enriched for miscarriage genes. Exposures to chemicals linked to miscarriage, and thus linked to decreased probability of live birth, may limit the inclusion of fetuses susceptible to adverse birth outcomes in epidemiology studies. Our findings have critical public health implications for successful pregnancies and the interpretation of adverse impacts of environmental chemical exposures on pregnancy.

Estimated Maternal Pesticide Exposure from Drinking Water and Heart Defects in Offspring

Our objective was to examine the relationship between estimated maternal exposure to pesticides in public drinking water and the risk of congenital heart defects (CHD). We used mixed-effects logistic regression to analyze data from 18,291 nonsyndromic cases with heart defects from the Texas Birth Defects Registry and 4414 randomly-selected controls delivered in Texas from 1999 through 2005. Water district-level pesticide exposure was estimated by linking each maternal residential address to the corresponding public water supply district’s measured atrazine levels. We repeated analyses among independent subjects from the National Birth Defects Prevention Study (NBDPS) (1620 nonsyndromic cases with heart defects and 1335 controls delivered from 1999 through 2005). No positive associations were observed between high versus low atrazine level and eight CHD subtypes or all included heart defects combined. These findings should be interpreted with caution, in light of potential misclassification and relatively large proportions of subjects with missing atrazine data. Thus, more consistent and complete monitoring and reporting of drinking water contaminants will aid in better understanding the relationships between pesticide water contaminants and birth defects.

Association of Long-Term Pesticide Exposure and Biologic Parameters in Female Farm Workers in Tanzania: A Cross Sectional Study

The study aimed to assess the association of long-term pesticide exposure (≥5 years) with hematological, serum biochemical parameters and acetylcholinesterase activity in farm workers. These pesticides included organophosphorus pesticides, carbamates, pyrethroids, dithiocarbamates, and other pesticides such as endosulfan. Applying a cross-sectional study design, 69 females from a pesticide-exposed farm population and 30 females from a district not using pesticides (reference group) were studied. The mean red cell corpuscular volume and hematocrit values were significantly lower (74.7 ± 9.1 fl; 95% CI 72.5-76.9 and 32.0% ± 4.6%; 95% CI 30.9-33.1, respectively) in the exposed compared to the reference group, whereas mean corpuscular hemoglobin concentration and platelets were significantly higher (37.4 ± 3.8 g/dL; 95% CI 36.5-38.3 and 374.1 ± 95.3/L; 95% CI 351.2-396.9, respectively) in the exposed compared to the reference group. Mean serum glutamic oxaloacetate transaminase (20.7 ± 8.9 U/L; 95% CI 18.5-22.9) and creatinine (83.9 ± 6.6 μmol/L; 95% CI 82.3-85.5) were significantly higher in the exposed compared to the reference group. A higher mean esterase activity (AChE 0.6 ± 0.2 mM/min/mg protein; 95% CI 0.56-0.7; BChE 0.9 ± 0.4 mM/min/mg protein; 95% CI 0.9-1.1) was noted in the exposed group. Regression models suggest that occupational exposure (p < 0.001) could be a predictor of esterase (AChE and BChE) activity and biochemical changes (β = 0.4, 95% CI: 0.3-0.5; β = 0.7, 95% CI: 0.6-0.9, respectively). Long-term pesticide exposure affects the hemato-biochemical and esterase responses, establishing the need for further studies.

Organochlorine pesticides in follicular fluid of women undergoing assisted reproductive technologies from central China

Female infertility rates have increased by approximately 4% since the 1980s. There is evidence of adverse effects on female fertility in relation to exposure of chemical pollution in recent years. Follicular fluid samples were collected from 127 woman patients (aged 20-35) who underwent assisted reproductive technologies (ART) and had no records indicating occupational exposure to OCPs. Seventeen OCPs were analyzed in this study. The results showed that methoxychlor was dominant, accounted for 13.4% of total OCPs with a mean concentration of 167.9 ± 33.9 ng/g lipid weight (lw), followed by heptachlor-epoxide, hexachlorocyclohexanes, endrin and DDT. The concentrations of OCPs in the follicular fluid samples in the present study were moderate in comparison with those reported from developed or industrialized countries. All these pollutants can accumulate in different tissues of human body through diet, drinking water and respiration. No correlation between patient age and OCP concentrations was observed in this study.

[Epidemiology of loss pregnancy]

OBJECTIVES

Study of epidemiology of pregnancy loss.

MATERIALS AND METHOD

A systematic review of the literature was performed using Pubmed and the Cochrane library databases and the guidelines from main international societies.

RESULTS

The occurrence of first trimester miscarriage is 12% of pregnancies and 25% of women. Miscarriage risk factors are ages of woman and man, body mass index greater than or equal to 25kg/m(2), excessive coffee drinking, smoking and alcohol consumption, exposure to magnetic fields and ionizing radiation, history of abortion, some fertility disorders and impaired ovarian reserve. Late miscarriage (LM) complicates less than 1% of pregnancies. Identified risk factors are maternal age, low level of education, living alone, history of previous miscarriage, of premature delivery and of previous termination of pregnancy, any uterine malformation, trachelectomy, existing bacterial vaginosis, amniocentesis, a shortened cervix and a dilated cervical os with prolapsed membranes. Fetal death in utero has a prevalence of 2% in the world and 5/1000 in France. Its main risk factors are detailed in the chapter.

Low-dose effects of hormones and endocrine disruptors

Endogenous hormones have effects on tissue morphology, cell physiology, and behaviors at low doses. In fact, hormones are known to circulate in the part-per-trillion and part-per-billion concentrations, making them highly effective and potent signaling molecules. Many endocrine-disrupting chemicals (EDCs) mimic hormones, yet there is strong debate over whether these chemicals can also have effects at low doses. In the 1990s, scientists proposed the "low-dose hypothesis," which postulated that EDCs affect humans and animals at environmentally relevant doses. This chapter focuses on data that support and refute the low-dose hypothesis. A case study examining the highly controversial example of bisphenol A and its low-dose effects on the prostate is examined through the lens of endocrinology. Finally, the chapter concludes with a discussion of factors that can influence the ability of a study to detect and interpret low-dose effects appropriately.

The effects of oxidative stress on female reproduction: a review

Oxidative stress (OS), a state characterized by an imbalance between pro-oxidant molecules including reactive oxygen and nitrogen species, and antioxidant defenses, has been identified to play a key role in the pathogenesis of subfertility in both males and females. The adverse effects of OS on sperm quality and functions have been well documented. In females, on the other hand, the impact of OS on oocytes and reproductive functions remains unclear. This imbalance between pro-oxidants and antioxidants can lead to a number of reproductive diseases such as endometriosis, polycystic ovary syndrome (PCOS), and unexplained infertility. Pregnancy complications such as spontaneous abortion, recurrent pregnancy loss, and preeclampsia, can also develop in response to OS. Studies have shown that extremes of body weight and lifestyle factors such as cigarette smoking, alcohol use, and recreational drug use can promote excess free radical production, which could affect fertility. Exposures to environmental pollutants are of increasing concern, as they too have been found to trigger oxidative states, possibly contributing to female infertility. This article will review the currently available literature on the roles of reactive species and OS in both normal and abnormal reproductive physiological processes. Antioxidant supplementation may be effective in controlling the production of ROS and continues to be explored as a potential strategy to overcome reproductive disorders associated with infertility. However, investigations conducted to date have been through animal or in vitro studies, which have produced largely conflicting results. The impact of OS on assisted reproductive techniques (ART) will be addressed, in addition to the possible benefits of antioxidant supplementation of ART culture media to increase the likelihood for ART success. Future randomized controlled clinical trials on humans are necessary to elucidate the precise mechanisms through which OS affects female reproductive abilities, and will facilitate further explorations of the possible benefits of antioxidants to treat infertility.

Assessment of time to pregnancy and spontaneous abortion status following occupational exposure to organic solvents mixture

PURPOSE

Due to increasing usage of chemicals in various industries, occupational exposure of women with these materials is unavoidable. Nowadays, some studies indicate adverse effects of exposure to these chemicals, especially organic solvents on the reproductive system of females. This study aimed to assess the relationship between spontaneous abortion and occupational exposure to organic solvents mixture in pharmaceutical industry.

METHODS

This study was carried out in a pharmaceutical factory located in the suburb of Tehran in 2010. During the study, married women who were working in the factory laboratory units and had exposure to mixed organic solvents were compared with married women who were working in the packing units of the factory without occupational exposure to organic solvents in terms of spontaneous abortion frequency and duration of pregnancy using statistical methods.

RESULTS

In this study, the frequency of spontaneous abortion in employees with and without exposure to organic solvents mixture was 10.7 and 2.9% respectively. This study showed that even after adjustment for confounding factors, there was a significant correlation between spontaneous abortion and occupational exposure to organic solvents mixture and this correlation increased with increasing levels of exposure to organic solvents. Also, a significant correlation was observed between occupational exposure to mixed organic solvents and waiting time to become pregnant (TTP). Furthermore, this study showed that even after adjustment for confounding variables, shift workers were significantly more affected by spontaneous abortion compared to daytime workers (P < 0.001). Also, in our study, synergistic effect between shift working and occupational exposure to organic solvents mixture on spontaneous abortion was seen.

CONCLUSIONS

According to the results of this study, since there is probability of spontaneous abortion resulting from occupational exposure to various chemicals including organic solvents, recommendation to review the status of occupational exposure of workers can be helpful in improving fertility consultations and reproductive health.

Environment and women's reproductive health

BACKGROUND

There is significant evidence that continuous and prolonged exposure to several endocrine disrupting chemicals (EDC) is a risk factor for reduced fertility and fecundity in women. There is also evidence that ED exposure has trans-generational effects. In this systematic review, we evaluate the evidence for an association between EDC exposure and women's reproductive health.

METHODS

Studies were found by searching the PubMed database for articles published up to 2010. Associations between ED exposure and women's reproductive health reported in the PubMed database are summarized and classified as fertility and fecundity, pregnancy outcomes, transgenerational exposure and effects.

RESULTS

Epidemiological studies on EDCs are not always consistent, in part due to limitations imposed by practical constraints. In order to make progress in this field, we recommend taking advantage of biomonitoring and biobanks, including the development of appropriate biomarkers, and taking into greater consideration modulating factors such as genetic polymorphisms and dietary habits. Further human studies are warranted with particular focus on impaired fertility/fecundity associated with currently widespread ED (e.g. bisphenol A, phthalates and polybrominated flame retardants).

CONCLUSIONS

A detailed appraisal of compounds specifically related to adverse reproductive outcomes is very important for prevention and risk-communication strategies. Besides research needs, the current evidence is sufficient to prompt precautionary actions to protect women's reproductive health.

Effects of pirimiphos-methyl (an organophosphate insecticide) on the fertility of adult male rats

BACKGROUND

Organophosphate insecticides represent one of the most widely used classes of pesticides with high potential for human exposure in both rural and residential environments.

OBJECTIVE

In the present study, we investigated the effects of pirimiphos-methyl (0, 2-diethylamino-6-methylpirimidin-4-yl O, O-dimethyl phosphorothioate), an organophosphothioate pesticide, on male rat reproductive performances.

METHODS

A total of 24 adult Wistar rats were divided into 4 groups of 6 animals each and orally treated with 0, 41.67, 62.5 or 125 mg/kg of pirimiphos-methyl for 90 days.

RESULTS

Results from the study showed a significant increase (p<0.05) in feed consumption, body weight gain, relative testis and epidiydimis weights and intra-testicular cholesterol level in rats receiving the test substance at doses of 62.5 or 125 mg/kg whereas a significant decrease (p<0.05) in serum total protein, sperm density and motility, fertility and parturition indices and pups sex-ratio (M/F) was recorded in animals treated with 125 mg/Kg of pirimiphos methyl. Histological findings also indicated enlargement of interstitial space, inhibition of spermatogenesis, rarefaction of Leydig cells and oedema in testes compared to control animals.

CONCLUSION

It could then be concluded that pirimiphos-methyl (62.5 and 125 mg/kg) is detrimental to the reproductive potentials of male rats.

Epidemiologic evidence of relationships between reproductive and child health outcomes and environmental chemical contaminants

This review summarizes the level of epidemiologic evidence for relationships between prenatal and/or early life exposure to environmental chemical contaminants and fetal, child, and adult health. Discussion focuses on fetal loss, intrauterine growth restriction, preterm birth, birth defects, respiratory and other childhood diseases, neuropsychological deficits, premature or delayed sexual maturation, and certain adult cancers linked to fetal or childhood exposures. Environmental exposures considered here include chemical toxicants in air, water, soil/house dust and foods (including human breast milk), and consumer products. Reports reviewed here included original epidemiologic studies (with at least basic descriptions of methods and results), literature reviews, expert group reports, meta-analyses, and pooled analyses. Levels of evidence for causal relationships were categorized as sufficient, limited, or inadequate according to predefined criteria. There was sufficient epidemiological evidence for causal relationships between several adverse pregnancy or child health outcomes and prenatal or childhood exposure to environmental chemical contaminants. These included prenatal high-level methylmercury (CH(3)Hg) exposure (delayed developmental milestones and cognitive, motor, auditory, and visual deficits), high-level prenatal exposure to polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), and related toxicants (neonatal tooth abnormalities, cognitive and motor deficits), maternal active smoking (delayed conception, preterm birth, fetal growth deficit [FGD] and sudden infant death syndrome [SIDS]) and prenatal environmental tobacco smoke (ETS) exposure (preterm birth), low-level childhood lead exposure (cognitive deficits and renal tubular damage), high-level childhood CH(3)Hg exposure (visual deficits), high-level childhood exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (chloracne), childhood ETS exposure (SIDS, new-onset asthma, increased asthma severity, lung and middle ear infections, and adult breast and lung cancer), childhood exposure to biomass smoke (lung infections), and childhood exposure to outdoor air pollutants (increased asthma severity). Evidence for some proven relationships came from investigation of relatively small numbers of children with high-dose prenatal or early childhood exposures, e.g., CH(3)Hg poisoning episodes in Japan and Iraq. In contrast, consensus on a causal relationship between incident asthma and ETS exposure came only recently after many studies and prolonged debate. There were many relationships supported by limited epidemiologic evidence, ranging from several studies with fairly consistent findings and evidence of dose-response relationships to those where 20 or more studies provided inconsistent or otherwise less than convincing evidence of an association. The latter included childhood cancer and parental or childhood exposures to pesticides. In most cases, relationships supported by inadequate epidemiologic evidence reflect scarcity of evidence as opposed to strong evidence of no effect. This summary points to three main needs: (1) Where relationships between child health and environmental exposures are supported by sufficient evidence of causal relationships, there is a need for (a) policies and programs to minimize population exposures and (b) population-based biomonitoring to track exposure levels, i.e., through ongoing or periodic surveys with measurements of contaminant levels in blood, urine and other samples. (2) For relationships supported by limited evidence, there is a need for targeted research and policy options ranging from ongoing evaluation of evidence to proactive actions. (3) There is a great need for population-based, multidisciplinary and collaborative research on the many relationships supported by inadequate evidence, as these represent major knowledge gaps. Expert groups faced with evaluating epidemiologic evidence of potential causal relationships repeatedly encounter problems in summarizing the available data. A major driver for undertaking such summaries is the need to compensate for the limited sample sizes of individual epidemiologic studies. Sample size limitations are major obstacles to exploration of prenatal, paternal, and childhood exposures during specific time windows, exposure intensity, exposure-exposure or exposure-gene interactions, and relatively rare health outcomes such as childhood cancer. Such research needs call for investments in research infrastructure, including human resources and methods development (standardized protocols, biomarker research, validated exposure metrics, reference analytic laboratories). These are needed to generate research findings that can be compared and subjected to pooled analyses aimed at knowledge synthesis.

Exposure to pesticides and time to pregnancy among female greenhouse workers

The aim of the study was to evaluate the possible effect of maternal work in greenhouses, as characterised by potentially high exposure to pesticides, on female fertility. Nine hundred and ten women active in 34 greenhouse flower growing enterprises in 1998-2000, with at least one pregnancy, and aged less than 50 years were identified. Seven hundred and seventeen (79%) agreed to be interviewed and reported 1699 pregnancies, of which 713 had complete information on time to pregnancy and occupation. These pregnancies were classified as exposed or non-exposed according to the maternal occupation in greenhouses at the moment of conception and analysed using logistic regression and survival analysis methods. We found a slightly higher proportion of pregnancies with delayed conception (more than 6 months) in the exposed group. However, after adjustment for confounding variables, the estimated hazard ratio for reduced fertility among the exposed was not significantly different to that of the non-exposed pregnancies (HR=0.96, 95%CI: 0.81, 1.13). A significant reduction in fecundability was observed in older women and with a daily consumption of one or more alcoholic beverages or cups of tea.