Spontaneous abortions in an industrialized community in Finland

Associations between multiple metal exposure and fertility in women: A nested case-control study

Metal pollution can cause a decline in female fertility, however, previous studies have focused more on the effect of a single metal on fertility. In this study, we evaluated the effect of metal mixtures on female fertility based on nested case-control samples. The plasma levels of 22 metal elements from 180 women were determined by an inductively coupled plasma mass spectrometer (ICP-MS). Minimum absolute contraction and selection operator (LASSO) penalty regression selected metals with the greatest influence on clinical outcome. Logistic regression was used to analyze the correlation between single metals and fertility while a Bayesian kernel function regression (BKMR) model was used to analyze the effect of mixed metals. Eight metals (Calcium (Ca), Chromium (Cr), Cobalt (Co), Copper (Cu), Zinc (Zn), Rubidium (Rb), Strontium (Sr) and Zirconium (Zr)) were selected by LASSO regression for subsequent analysis. After adjusting for covariates, the logistic model showed that Cu (Odds Ratio(OR):0.33, 95% CI: 0.13 - 0.84) and Co (OR:0.38, 95% CI: 0.15 -0.94) caused a significant reduction in fertility, and identified the protective effect of Zn (OR: 2.96, 95% CI:1.21 -7.50) on fertility. Trend tests showed that increased Cr, Cu, and Rb levels were associated with reduced fertility. The BKMR model showed that Cr, Co, Cu, and Rb had a nonlinear relationship with fertility decline when controlling for the concentrations of other metals and suggested that Cu and Cr might exert an influence on fertility. Analysis showed a negative correlation between Cu, Cr, Co, Rb, and fertility, and a positive correlation between Zn and fertility. Furthermore, we found evidence for the interaction between Cu and Cr. Our findings require further validation and may identify new mechanisms in the future.

The Impact of Oxidative Stress of Environmental Origin on the Onset of Placental Diseases

Oxidative stress (OS) plays a pivotal role in placental development; however, abnormal loads in oxidative stress molecules may overwhelm the placental defense mechanisms and cause pathological situations. The environment in which the mother evolves triggers an exposure of the placental tissue to chemical, physical, and biological agents of OS, with potential pathological consequences. Here we shortly review the physiological and developmental functions of OS in the placenta, and present a series of environmental pollutants inducing placental oxidative stress, for which some insights regarding the underlying mechanisms have been proposed, leading to a recapitulation of the noxious effects of OS of environmental origin upon the human placenta.

Toxicity of formulants and heavy metals in glyphosate-based herbicides and other pesticides

The major pesticides of the world are glyphosate-based herbicides (GBH), and their toxicity is highly debated. To understand their mode of action, the comparative herbicidal and toxicological effects of glyphosate (G) alone and 14 of its formulations were studied in this work, as a model for pesticides. GBH are mixtures of water, with commonly 36-48% G claimed as the active principle. As with other pesticides, 10-20% of GBH consist of chemical formulants. We previously identified these by mass spectrometry and found them to be mainly families of petroleum-based oxidized molecules, such as POEA, and other contaminants. We exposed plants and human cells to the components of formulations, both mixed and separately, and measured toxicity and human cellular endocrine disruption below the direct toxicity experimentally measured threshold. G was only slightly toxic on plants at the recommended dilutions in agriculture, in contrast with the general belief. In the short term, the strong herbicidal and toxic properties of its formulations were exerted by the POEA formulant family alone. The toxic effects and endocrine disrupting properties of the formulations were mostly due to the formulants and not to G. In this work, we also identified by mass spectrometry the heavy metals arsenic, chromium, cobalt, lead and nickel, which are known to be toxic and endocrine disruptors, as contaminants in 22 pesticides, including 11 G-based ones. This could also explain some of the adverse effects of the pesticides. In in vivo chronic regulatory experiments that are used to establish the acceptable daily intakes of pesticides, G or other declared active ingredients in pesticides are assessed alone, without the formulants. Considering these new data, this assessment method appears insufficient to ensure safety. These results, taken together, shed a new light on the toxicity of these major herbicides and of pesticides in general.

Editor's Highlight: Exposure to CrVI during Early Pregnancy Increases Oxidative Stress and Disrupts the Expression of Antioxidant Proteins in Placental Compartments

Epidemiologic studies document relationships between chromium VI (CrVI) exposure and increased risk of spontaneous abortion, stillbirth, preterm birth, and neonatal death in pregnant women. Environmental contamination with CrVI is a growing problem both in the United States and developing countries. CrVI is widely used in numerous industries. This study was designed to understand the mechanism of CrVI toxicity on placental oxidative stress and antioxidant (AOX) machinery. Pregnant mother rats were treated with or without CrVI (50 ppm K2Cr2O7) through drinking water from gestational day (GD) 9.5-14.5, and placentas were analyzed on GD 18.5. Results indicated that CrVI reduced the trophoblast cell population. CrVI increased reactive oxygen species (ROS) and decreased the expression of AOX proteins. CrVI disrupts the trophoblast proliferation of the placenta. This study provides insight into the critical role of AOXs in placental function.

Chromium VI - Induced developmental toxicity of placenta is mediated through spatiotemporal dysregulation of cell survival and apoptotic proteins

Environmental contamination with hexavalent chromium (CrVI) is a growing problem both in the U.S and developing countries. CrVI is a heavy-metal endocrine disruptor; women working in Cr industries exhibit an increased incidence of premature abortion and infertility. The current study was designed to understand the mechanism of CrVI toxicity on placental cell survival/death pathways. Pregnant mothers were treated with or without CrVI (50ppmK₂Cr₂O₇) through drinking water from gestational day (GD) 9.5-14.5, and placentas were analyzed on GD 18.5. Results indicated that CrVI increased apoptosis of trophoblasts, vascular endothelium of the metrial glands and yolk sac epithelium through caspase-3 and p53-dependent pathways. CrVI increased apoptosis in labyrinth and basal zones in a caspase-3-independent manner via AIF, and through an ATM-p53-NOXA-PUMA-p27 network. CrVI downregulated cell survival proteins Bcl-2, Bcl-XL and XIAP in the placenta. CrVI disrupts placental histoarchitecture and increases cell death by spatiotemporal modulation of apoptotic signaling.

Resveratrol protects the ovary against chromium-toxicity by enhancing endogenous antioxidant enzymes and inhibiting metabolic clearance of estradiol

Resveratrol (RVT), a polyphenolic component in grapes and red wine, has been known for its cytoprotective actions against several diseases. However, beneficial effects of RVT against early exposure to endocrine disrupting chemicals (EDCs) have not been understood. EDCs are linked to several ovarian diseases such as premature ovarian failure, polycystic ovary syndrome, early menopause and infertility in women. Hexavalent chromium (CrVI) is a heavy metal EDC, and widely used in >50 industries. Environmental contamination with CrVI in the US is rapidly increasing, predisposing the human to several illnesses including cancers and still birth. Our lab has been involved in determining the molecular mechanism of CrVI-induced female infertility and intervention strategies to mitigate CrVI effects. Lactating mother rats were exposed to CrVI (50ppm potassium dichromate) from postpartum days 1-21 through drinking water with or without RVT (10mg/kg body wt., through oral gavage daily). During this time, F1 females received respective treatments through mother's milk. On postnatal day (PND) 25, blood and the ovary, kidney and liver were collected from the F1 females for analyses. CrVI increased atresia of follicles by increasing cytochrome C and cleaved caspase-3; decreasing antiapoptotic proteins; decreasing estradiol (E2) biosynthesis and enhancing metabolic clearance of E2, increasing oxidative stress and decreasing endogenous antioxidants. RVT mitigated the effects of CrVI by upregulating cell survival proteins and AOXs; and restored E2 levels by inhibiting hydroxylation, glucuronidation and sulphation of E2. This is the first study to report the protective effects of RVT against any toxicant in the ovary.

A fetal whole ovarian culture model for the evaluation of CrVI-induced developmental toxicity during germ cell nest breakdown

Prenatal exposure to endocrine disrupting chemicals (EDCs), including bisphenol A, dioxin, pesticides, and cigarette smoke, has been linked to several ovarian diseases such as premature ovarian failure (POF) and early menopause in women. Hexavalent chromium (CrVI), one of the more toxic heavy metals, is widely used in more than 50 industries. As one of the world's leading producers of Cr compounds, the U.S. is facing growing challenges in protecting human health against adverse effects of CrVI. Our recent findings demonstrated that in vivo CrVI exposure during gestational period caused POF in F1 offspring. Our current research focus is three-fold: (i) to identify the effect of CrVI on critical windows of great vulnerability of fetal ovarian development; (ii) to understand the molecular mechanism of CrVI-induced POF; (iii) to identify potential intervention strategies to mitigate or inhibit CrVI effects. In order to accomplish these goals we used a fetal whole ovarian culture system. Fetuses were removed from the normal pregnant rats on gestational day 13.5. Fetal ovaries were cultured in vitro for 12 days, and treated with or without 0.1 ppm potassium dichromate (CrVI) from culture day 2-8, which recapitulated embryonic day 14.5-20.5, in vivo. Results showed that CrVI increased germ cell/oocyte apoptosis by increasing caspase 3, BAX, p53 and PUMA; decreasing BCL2, BMP15, GDF9 and cKIT; and altering cell cycle regulatory genes and proteins. This model system may serve as a potential tool for high throughput testing of various drugs and/or EDCs in particular to assess developmental toxicity of the ovary.

Identifying a novel role for X-prolyl aminopeptidase (Xpnpep) 2 in CrVI-induced adverse effects on germ cell nest breakdown and follicle development in rats

Environmental exposure to endocrine-disrupting chemicals (EDCs) is one cause of premature ovarian failure (POF). Hexavalent chromium (CrVI) is a heavy metal EDC widely used in more than 50 industries, including chrome plating, welding, wood processing, and tanneries. Recent data from U.S. Environmental Protection Agency indicate increased levels of Cr in drinking water from several American cities, which potentially predispose residents to various health problems. Recently, we demonstrated that gestational exposure to CrVI caused POF in F1 offspring. The current study was performed to identify the molecular mechanism behind CrVI-induced POF. Pregnant rats were treated with 25 ppm of potassium dichromate from Gestational Day (GD) 9.5 to GD 14.5 through drinking water, and the fetuses were exposed to CrVI through transplacental transfer. Ovaries were removed from the fetuses or pups on Embryonic Day (ED) 15.5, ED 17.5, Postnatal Day (PND) 1, PND 4, or PND 25, and various analyses were performed. Results showed that gestational exposure to CrVI: 1) increased germ cell/oocyte apoptosis and advanced germ cell nest (GCN) breakdown; 2) increased X-prolyl aminopeptidase (Xpnpep) 2, a POF marker in humans, during GCN breakdown; 3) decreased Xpnpep2 during postnatal follicle development; and 4) increased colocalization of Xpnpep2 with Col3 and Col4. We also found that Xpnpep2 inversely regulated the expression of Col1, Col3, and Col4 in all the developmental stages studied. Thus, CrVI advanced GCN breakdown and increased follicle atresia in F1 female progeny by targeting Xpnpep2.

Quality of the Finnish Hospital Discharge Register: a systematic review

AIMS

The Finnish Hospital Discharge Register (FHDR) is one of the oldest individual level hospital discharge registers and has been intensively used for research purposes. The aim of this study was to gather information concerning the quality of FHDR into one place in terms of a systematic review of validation studies that compare data to external information.

METHODS

Several reference databases were searched for validity articles published until January 2012. For each included study, focus of validation, register years examined, number of compared observations, external source(s) of data, summary of validation results, and conclusions concerning the validity of FHDR were extracted.

RESULTS

In total, 32 different studies comparing FHDR data to external information were identified. Most of the studies examined validity in the case of vascular disease, mental disorders or injuries. More than 95% of discharges could be identified from the register. Positive predictive value (PPV) for common diagnoses was between 75 and 99%.

CONCLUSIONS

Completeness and accuracy in the register seem to vary from satisfactory to very good in the register as long as the recognised limitations are taking into account. Poor recording of subsidiary diagnoses and secondary operations and other rarely used items are the most obvious limitations in validity, but do not compromise the value of data in FHDR in being used in studies that are not feasible to conduct otherwise.

Paternal and maternal exposure to welding fumes and metal dusts or fumes and adverse pregnancy outcomes

OBJECTIVE

We assessed whether paternal exposure prior to conception and maternal exposure during pregnancy to welding fumes (WF) and metal dusts or fumes (MD/F) independently and jointly increases the risk of preterm delivery, low birth weight, and small-for-gestational age.

METHODS

The study population was selected from The Finnish Prenatal Environment and Health Study of 2,568 newborns (response rate 94%) and included 1,670 women who worked during pregnancy of which 68 were exposed either to WF and/or MD/F.

RESULTS

The risk of SGA was related to maternal exposure to WF only (adjusted OR = 1.78; 95% CI 0.53-5.99), MD/F only (adjusted OR = 1.77; 95% CI 0.38-8.35) and both exposures (2.92; 1.26-6.78). The corresponding effect estimates for preterm delivery were 2.66 (0.32-22.08), 5.64 (1.14-27.81) and for birth weight below 3,000 g 3.79 (1.09-13.19), 1.85 (0.56-6.14) and 1.70 (0.70-4.15), respectively. There was some suggestive, inconsistent evidence that the risk of preterm delivery and SGA is related to paternal exposure to WF.

CONCLUSIONS

The present results provide evidence that maternal exposure to WF or MD/F combination during pregnancy may reduce fetal growth and suggestive evidence that paternal exposure to WF may increase the risk of preterm delivery and small-for-gestational age. The small number of exposed women and the lack of data for exposure concentrations suggest the need for further study to verify our findings.

Dust and chemical exposures, and miscarriage risk among women textile workers in Shanghai, China

INTRODUCTION

To investigate possible associations between miscarriage and occupational exposures in the Shanghai textile industry.

METHODS

A retrospective cohort study of miscarriages among 1752 women in the Shanghai textile industry was conducted. Reproductive history was self-reported by women and occupational work histories were collected from factory personnel records. Occupational exposures were assigned by linking work history information to an industry-specific job-exposure matrix informed by factory-specific textile process information and industrial hygiene assessments. Estimates of cotton dust and endotoxin exposure were also assigned. Odds ratios (OR) and 95% CI were estimated by multivariate logistic regression, with adjustment for age at pregnancy, educational level, smoking status of the woman and her spouse, use of alcohol, and woman's year of birth.

RESULTS

An elevation in risk of a spontaneously aborted first pregnancy was associated with exposure to synthetic fibres (OR 1.89, 95% CI 1.20 to 3.00) and mixed synthetic and natural fibres (OR 3.31, 95% CI 1.30 to 8.42). No increased risks were observed for women working with solvents, nor were significant associations observed with quantitative cotton dust or endotoxin exposures. Associations were robust and similar when all pregnancies in a woman's reproductive history were considered.

CONCLUSIONS

Occupational exposure to synthetic fibres may cause miscarriages, and this possibility should be the subject of further investigation.

Aborto espontâneo em mulheres residentes nas proximidades do parque industrial do município do Rio Grande - RS

Estudo transversal que objetivou identificar a prevalência de abortos espontâneos e fatores associados em mulheres em idade reprodutiva residentes nas proximidades de um parque industrial. A amostra foi de 285 mulheres expostas à poluição e 280 não expostas. Os dados foram coletados por meio de um instrumento com questões fechadas, em 2004 e analisados pelo teste qui-quadrado e regressão logística, mostraram prevalência de abortos espontâneos de 17,7%. Na análise bivariada associaram-se com o desfecho: idade da menarca (OR=0,26; p=0,0008); número de filhos (OR=4,00; p=0,001). Na análise multivariada a idade da menarca entre 11 e 13 anos (OR=0,32; p=0,005), presença de três ou mais filhos (OR=2,92; p=0,03) e história de baixo peso ao nascer (OR=2,39; p=0,049) associaram-se com aborto espontâneo. Não houve associação com o local de moradia nas proximidades do parque industrial. Sugere-se a realização de estudos com biomarcadores para identificar possível influência do ambiente sobre a saúde reprodutiva, nessa população, ou afastar definitivamente essa suspeita.

Reproductive outcomes in an area adjacent to a petrochemical plant in southern Brazil

OBJECTIVE

To evaluate possible adverse reproductive outcomes in an area adjacent to a petrochemical plant in southern Brazil.

METHODS

A review of 17,113 birth records of the main hospital of the municipality of Montenegro, southern Brazil, from 1983 to 1998 was carried out. Three groups of cases were selected: (1) newborns with major congenital malformations; (2) newborns with low birth weight (<2,500 g); and (3) stillborns (>500 g). A control was assigned to each case. Controls were the first newborns weighing </= 12,500 g without malformations and of case-matching sex. Mother's residence during pregnancy was used as an exposure parameter. Statistical analyses were performed using Chi-square test or Fisher test, odds ratio, 0.05 significance level, and 95% confidence interval.

RESULTS

For unadjusted analysis, it was found a correlation between low birth weight and geographical proximity of mother's residence to the petrochemical plant (OR = 1.66; 95% CI = 1.01 - 2.72) or residence on the way of preferential wind direction (OR = 1.62; 95% CI = 1.03 - 2.56). When other covariates were added in the conditional logistic regression (maternal smoking habits, chronic disease and age), there was no association.

CONCLUSIONS

Despite final results were negative, low birth weight could be a good parameter of environmental contamination and should be closely monitored in the studied area.

Male and female occupation in relation to miscarriage and preterm delivery in central North Carolina

PURPOSE

This study was undertaken to evaluate the role of parental occupation in miscarriage and preterm delivery. Previous studies raise the possibility that both male and female exposures could affect pregnancy.

METHODS

Data from a population-based study of miscarriage and preterm delivery in central North Carolina were used to examine potential associations with male and female occupation. Medically treated miscarriage cases (n = 418), preterm delivery cases identified through hospital record review (n = 582), and term, normal birth weight controls (n = 787) were sought for telephone interview. The interview included information on jobs the woman held before and during the pregnancy, reports of her partner's job around the time of pregnancy, and information on potential confounding factors.

RESULTS

Female employment overall, or in specific jobs, around the time of conception or early pregnancy was not associated with the risk of miscarriage, whereas working during pregnancy, especially in the seventh month, was inversely associated with risk of preterm delivery. Male employment in several industrial occupations was weakly associated with miscarriage (adjusted odds ratios (OR) of 1.6 to 1.8), and somewhat more strongly associated with preterm delivery, particularly for chemists and sheet metal workers (adjusted OR over 3). Restriction to married men strengthened the associations.

CONCLUSIONS

Our results are limited by nonresponse, imprecision, incomplete identification of miscarriages, and lack of detailed occupational exposure information. Nonetheless, we found greater support for further examination of male compared to female jobs in relation to pregnancy outcome.

The first injustice: socioeconomic disparities, health services technology, and infant mortality

"Infant mortality has long been viewed as a synoptic indicator of the health and social condition of a population. In this article we examine critically the structure of this reflective capacity with a particular emphasis on how new health care technologies may have altered traditional pathways of social influence.... Current patterns of infant mortality in the United States provide a useful illustration of the dynamic interaction of underlying social forces and technological innovation in determining trends in health outcomes. We review the implications of this perspective for [future] sociological research into disparate infant mortality...."

Sociobiological risk factors for spontaneous abortion in Malaysia

OBJECTIVE

To evaluate the risk factors of spontaneous abortion.

METHODS

A case-control study was conducted by interviewing 350 women who were admitted to the university gynaecological unit for spontaneous abortion and 350 women who delivered normally at the university obstetric unit. Odds ratios, as the estimators of relative risks, were calculated.

RESULTS

The relative risk for spontaneous abortion among women in the age-group 30 to 39 years was 1.61 and among women above 40 years of age was 3.68 when compared to those below 30 years of age. In relation to career women, the relative risk of spontaneous abortion for housewives was 0.45. Ethnic group, parity, subfertility, previous induced abortion, ectopic pregnancy, contraception and menarcheal age did not influence the risk of spontaneous abortion.

CONCLUSION

Increasing age and a woman's career are significant risk factors of spontaneous abortion.

Review of epidemiologic studies of paternal occupational exposure and spontaneous abortion

The question of whether paternal exposures influence risk of spontaneous abortion is of great public interest, with the possibility supported by laboratory investigations. Thirty-nine studies of male occupational exposure and risk of spontaneous abortion were examined, with the methods and results tabulated. Many of those reports were limited by exposure data based on maternal report of the father's job title or by potentially inaccurate paternal reports of spontaneous abortion, though the quality of more recent studies is markedly enhanced. Mercury has been implicated most strongly based on recent studies that included quantitative exposure estimates; a number of studies showing associations for exposure to anesthetic gases. Suggestive associations have also been found inconsistently for exposure to lead, rubber manufacturing, selected solvents, and some pesticides. Further study is encouraged, but with more intensive effort to measure accurately both spontaneous abortion and occupational exposures.

Different effects of maternal and paternal education on early mortality in Norway

In order to separate the effects of maternal and paternal education on pregnancy outcome, a total population of 97,526 single, firstborn infants and their parents was studied. Census information from 1980 was linked to the Medical Birth Registry for 1978-82. Children of parents with high education (> 12 years) were the most likely to survive the first year of life. There was a linear association between parental education and infant mortality. Examining parental education jointly, it was found that the father's educational level had the greatest impact on stillbirth. Mother's educational level seemed to be more closely associated with postneonatal mortality. Possible mechanism to explain the association between educational level and infant mortality are discussed.

A study of the effect of perchloroethylene exposure on the reproductive outcomes of wives of dry-cleaning workers

The purpose of this investigation was to compare the reproductive outcomes of wives of men exposed to perchloroethylene in the dry-cleaning industry compared to those of wives of laundry workers. Seventeen female partners of dry cleaners and 32 partners of laundry workers were interviewed. The number of pregnancies and the standardized fertility ratios were similar between the two groups. Wives of dry cleaners did not have higher rates of spontaneous abortions. However, wives of dry cleaners were more than twice as likely to have a history of attempting to become pregnant for more than 12 months or to have sought care for an infertility problem. Cox proportional hazards models indicated that dry-cleaners' wives had half of the per-cycle pregnancy rate of wives of laundry workers, when controlling for other potential confounders (estimated rate ratio of 0.54, 95% C.I. = 0.23, 1.27).

Effect of employment and its correlates on spontaneous abortion risk

While several studies have examined the role of employment during pregnancy on reproductive risk, few have taken into account the potential selection pressures which may cause a woman to choose employment or non-employment during pregnancy. This study was designed to test the hypothesis that employment, or certain types or preconditions of employment, places a woman at increased risk for spontaneous abortion. A case-control study design, utilizing two control groups matched to the 334 cases for age and parity (total N = 981) allowed detailed comparisons of exposures and correlates during the index pregnancy. Control groups consisted of pregnant women (less than 25 wk gestation) and postnatal women. Detailed histories of employment in the 3 months preceding and 4 months following the last menstrual period (LMP), were taken, as well as data on such potential confounding variables as past obstetrical history and socioeconomic status. No significant differences were found between groups in terms of overall employment status. In addition, particular characteristics of jobs, such as hours worked per week, physical activity level, shift work or flexibility of hours were found to be non-significant when analyzed several ways. However, a marked difference in risk (OR for prenatal comparison 1.79, P less than 0.01; OR for postnatal comparison 2.13, P less than 0.001) was found for job motivation amongst full-time workers for risk, with those women stating they worked primarily out of financial need being at highest risk for abortion. This remained after using multiple logistic regression to control for family income and other socioeconomic variables, job characteristics and subjective measures of job satisfaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Advantages of a standard method for research on reproductive effects of occupation

A recent review of the literature identified several common methodological weaknesses in studies of the effects of occupational exposures on male and female reproductive processes. This paper suggests a strategy which addresses these problems, by the use of a standard method. The potential benefits include increased measurement reliability and statistical power, together with a systematic study of expected (background) rates, confounding effects, types of exposure and selection effects. Particular advantages are the avoidance of designating a group as non-exposed with attendant problems of bias, and in the longer term the study of multiple or rare exposures.

Spontaneous abortions and malformations in the offspring of nurses exposed to anaesthetic gases, cytostatic drugs, and other potential hazards in hospitals, based on registered information of outcome

Nurses working in selected departments of general hospitals in Finland were collected from a central register on health personnel in Finland. Using the Hospital Discharge Register and the Register of Congenital Malformations, case nurses were selected who had had a spontaneous abortion (N = 217) or a malformed child (N = 46) between the years 1973 and 1979. Controls consisted of three nurses who had had a normal birth; the control nurses were matched for age and hospital of employment. Information on exposure in the first trimester of pregnancy was sought through the head nurses of the hospitals. No significant increase in risk of spontaneous abortion or of malformation was observed after exposure to anaesthetic gases (odds ratio for spontaneous abortion 1.2), sterilising gases and soaps, or x-rays. Handling of cytostatic drugs did not affect the frequency of spontaneous abortion but was associated with malformations in the offspring. The odds ratio, based on eight cases, was 4.7 (p = 0.02) when the logistic model was adopted. The results suggest that the exposures investigated, other than cytostatic drugs, do not cause a strong reproductive risk. Further studies are needed, particularly on cytostatic drugs.

Sperm as an indicator of reproductive risk among petroleum refinery workers

A questionnaire study of men in a wastewater treatment plant of a petroleum refinery showed twice the rate of fetal loss in the period during employment in the plant compared with the periods before and after. Questions regarding the interpretation of that study and continuing concern about reproductive risk prompted us to perform a cross sectional evaluation of sperm concentration and morphology. After adjustment for an abstinence period, the mean sperm concentration of the 74 unexposed men did not differ significantly from that of the 34 exposed men (79.9 million/cm3 v 68.2 million/cm3, p(1) = 0.16). The two groups also had a similar proportion of sperm with abnormal morphology (49.1% v 44.5%, p(1) = 0.94). This lack of association remained when degree of exposure, age, use of alcohol and marijuana, past illness or fever, use of baths or sauna, and history of urological problems were considered. These results are most consistent with the absence of sperm mediated reproductive problems.

Previous experience of induced abortion as a risk factor for fetal death and preterm delivery

As part of a community-based study in Korea to evaluate the effects of previous induced abortion on length of gestation and pregnancy outcome of subsequent pregnancies, we analyzed data obtained from January 1979 to December 1981 on pregnancies reported to family health workers in Kang Hwa Island, Korea. The preterm, live-birth rates were not significantly associated with previous induced abortion. Overall, the life table-estimated fetal death rate for women enrolled at the eighth or earlier weeks of gestation was 13.7%, 10.2% for women with no previous induced abortion and 28.9% for women with previous induced abortion. The relative risk for fetal death for women who had undergone a previous abortion was 2.8; relative risk for parous women compared to nulliparous women was 3.4. After controlling for parity, previous induced abortion was not a significant variable for fetal death rate.