Effects of paternal occupational exposure on spontaneous abortions.

BACKGROUND: Paternal exposure to mutagenic agents has been suggested to affect pregnancy outcome adversely. METHODS: A nationwide data base of medically diagnosed spontaneous abortions and other pregnancies and national census data was used to evaluate the effects of men's occupational exposures on risk of spontaneous abortion in 99,186 pregnancies in Finland. Census data from the years 1975 and 1980 provided information about the occupation, industry, and socioeconomic status. A job-exposure classification was developed to classify women and their husbands according to possible occupational exposures on the basis of their occupational title and industry. RESULTS: In 10% of the pregnancies, the husband was exposed to one or more of the mutagens, and the rate of spontaneous abortion was unaffected (OR = 1.0). Of the 25 specific mutagenic exposures evaluated, paternal exposure to four (ethylene oxide, rubber chemicals, solvents used in refineries, and solvents used in the manufacturing of rubber products) was associated with an increased relative risk of spontaneous abortion. In addition, the risk of spontaneous abortion was higher among wives of rubber products workers than among unexposed men. CONCLUSIONS: Although there is some biological rationale for the findings of this study, these findings need to be confirmed by studies in which individual exposures can be measured directly.     

Male-mediated spontaneous abortion among spouses of stainless steel welders

OBJECTIVES: Male-mediated spontaneous abortion has never been documented for humans. The welding of stainless steel is associated with the pulmonary absorption of hexavalent chromium, which has genotoxic effects on germ cells in rodents. Clinical and early subclinical spontaneous abortions were examined among spouses of stainless-steel welders. METHODS: A cohort of first-pregnancy planners was recruited from members of the union of metal workers and 3 other trade unions. The cohort was followed for 6 menstrual cycles from the cessation of contraceptive use. Altogether, 280 pregnancies were conceived, of which 35 were detected by human chorionic gonadotrophic hormone analysis and did not survive to a clinically recognized pregnancy. Information on exposure was collected prospectively in relation to the outcome and was available for all cycles resulting in a pregnancy. Information on pregnancy outcome was collected for all 245 clinically recognized pregnancies. RESULTS: Increased risk of spontaneous abortion was found for pregnancies with exposure to paternal stainless-steel welding (adjusted relative risk 3.5, 95% confidence interval 1.3-9.1). The results were consistent in analyses of both biochemically and clinically recognized abortions. There was no increased risk for spontaneous abortion in pregnancies with paternal exposure to the welding of metals other than stainless steel. CONCLUSIONS: Male welding of stainless steel was associated with an increased risk of spontaneous abortion in spouses. A mutagenic effect of hexavalent chromium has been found previously in both somatic and germ cells, and the findings could be due to mutations in the male genome.     

Paternal exposure to mercury and spontaneous abortions.

The potential reproductive toxicity of mercury vapour was investigated by comparing the rate of spontaneous abortions among the wives of 152 workers occupationally exposed to mercury vapour with the rate among the wives of 374 controls in the same plant. The results indicate an increase in the rate of spontaneous abortions with an increasing concentration of mercury in the fathers' urine before pregnancy. At concentrations above 50 micrograms/l the risk of spontaneous abortion doubles (odds ratio (OR) = 2.26; 95% confidence interval (95% CI) = 0.99-5.23). Special care was taken to avoid bias in reporting abortions and known risk factors of spontaneous abortions do not seem to explain the results. Several biological mechanisms might account for them including, in particular, direct action of mercury on the paternal reproductive system and indirect toxicity to the mother or embryo through transport of mercury from the father. These indications could be of practical importance and should therefore be further documented.     

Paternal exposure to mercury and spontaneous abortions

The potential reproductive toxicity of mercury vapour was investigated by comparing the rate of spontaneous abortions among the wives of 152 workers occupationally exposed to mercury vapour with the rate among the wives of 374 controls in the same plant. The results indicate an increase in the rate of spontaneous abortions with an increasing concentration of mercury in the fathers' urine before pregnancy. At concentrations above 50 micrograms/l the risk of spontaneous abortion doubles (odds ratio (OR) = 2.26; 95% confidence interval (95% CI) = 0.99-5.23). Special care was taken to avoid bias in reporting abortions and known risk factors of spontaneous abortions do not seem to explain the results. Several biological mechanisms might account for them including, in particular, direct action of mercury on the paternal reproductive system and indirect toxicity to the mother or embryo through transport of mercury from the father. These indications could be of practical importance and should therefore be further documented.     

Influence of paternal exposure to oil and oil products on time to pregnancy and spontaneous abortions

The objective of this study was to evaluate the influence of exposure to oil and oil products among men on the time taken for their wives to conceive and on the incidence of spontaneous abortion among them. A cross-sectional study was performed by posting questionnaires to 1,269 men employed as offshore mechanics, offshore operators, offshore drilling personnel, car mechanics (the 'exposed' occupations) and carpenters ('unexposed'). The married men were asked to give a separate questionnaire to their wives for details about their pregnancies. The time elapsed between the beginning of coitus without contraception and the wife becoming pregnant (time to pregnancy) was analyzed with Cox regression analysis by calculating fecundability ratios for the pregnancies for the men exposed to oil and oil products as compared with the men who were not exposed. Spontaneous abortions were analyzed with logistic regression by calculating odds ratios for the pregnancies in which the men were exposed vs. not exposed. A total of 741 (58%) men returned the questionnaires. A total of 301 pregnancies were analyzed for time taken to conceive and 580 for spontaneous abortion. The results were adjusted for variables that could significantly influence conception time (previous infections of the reproductive system and coffee drinking) or the incidence of spontaneous abortion (mother's age, parity and smoking). The outcomes between the exposed and unexposed pregnancies showed no significant differences. Car mechanics had a lower fecundability ratio before 1992 than after 1992. Paternal exposure to hydrocarbons in the occupations studied did not seem to have had a major influence on time to conception or the incidence of spontaneous abortion among the wives of the men exposed to oil products.     

Risk of spontaneous abortion in workers exposed to toluene.

Rates of spontaneous abortions were determined using a reproductive questionnaire administered by personal interview to 55 married women with 105 pregnancies. They were employed in an audio speaker factory and were exposed to high concentrations of toluene (mean 88, range 50-150 ppm). These rates of spontaneous abortion were compared with those among 31 women (68 pregnancies) who worked in other departments in the same factory and had little or no exposure to toluene (0-25 ppm), as well as with a community control group of women who underwent routine antenatal and postnatal care at public maternal health clinics (190 women with 444 pregnancies). Significantly higher rates for spontaneous abortions were noted in the group with high exposure to toluene (12.4 per 100 pregnancies) compared with those in the internal control group (2.9 per 100 pregnancies) and in the external control group (4.5 per 100 pregnancies). Among the exposed women, significant differences were also noted in the rates of spontaneous abortion before employment (2.9 per 100 pregnancies) and after employment in the factory (12.6 per 100 pregnancies). Almost all the women were nonsmokers and did not drink; other known risk factors such as maternal age at pregnancy, order of gravidity, and race were not likely to explain the results. Thus, specific exposure to toluene seems to be associated with a risk of foetal loss.     

Risk of spontaneous abortion in workers exposed to toluene.

Rates of spontaneous abortions were determined using a reproductive questionnaire administered by personal interview to 55 married women with 105 pregnancies. They were employed in an audio speaker factory and were exposed to high concentrations of toluene (mean 88, range 50-150 ppm). These rates of spontaneous abortion were compared with those among 31 women (68 pregnancies) who worked in other departments in the same factory and had little or no exposure to toluene (0-25 ppm), as well as with a community control group of women who underwent routine antenatal and postnatal care at public maternal health clinics (190 women with 444 pregnancies). Significantly higher rates for spontaneous abortions were noted in the group with high exposure to toluene (12.4 per 100 pregnancies) compared with those in the internal control group (2.9 per 100 pregnancies) and in the external control group (4.5 per 100 pregnancies). Among the exposed women, significant differences were also noted in the rates of spontaneous abortion before employment (2.9 per 100 pregnancies) and after employment in the factory (12.6 per 100 pregnancies). Almost all the women were nonsmokers and did not drink; other known risk factors such as maternal age at pregnancy, order of gravidity, and race were not likely to explain the results. Thus, specific exposure to toluene seems to be associated with a risk of foetal loss.     

Shift work, nitrous oxide exposure, and spontaneous abortion among Swedish midwives.

OBJECTIVES: To study the relation between irregular work hours, nitrous oxide (N2O) exposure, and the risk of spontaneous abortion. METHODS: All 3985 female members of the Swedish Midwives Association in 1989, born in 1940 or later, received a questionnaire on exposure before and during all of their pregnancies. Questions on work conditions covered occupation, extent of employment, workplace, work schedules, use of anaesthetics, and work load. The association between exposure variables and spontaneous abortion was analysed by logistic regression models. RESULTS: Night work and three shift schedules among midwives showed increased odds ratios (ORs) (95% confidence intervals (95% CI)) 1.63 (0.95-2.81) and 1.49 (0.86-2.59), respectively. The ORs of late spontaneous abortions (after the 12th week of pregnancy) was increased for night work 3.33 (1.13-9.87). Use of N2O (> 50% of the deliveries) was not associated with increased risk of spontaneous abortion OR 0.95 (0.62-1.47). Frequent or permanent shortage of staff was related to an increased risk of spontaneous abortions before the 13th week of pregnancy. CONCLUSIONS: The results support the hypothesis that night work and high work load increase the risk of spontaneous abortion.     

Occupational exposure to antineoplastic agents: self-reported miscarriages and stillbirths among nurses and pharmacists.

Insult to the germ cells of an ovum or sperm prior to pregnancy as well as exposures to a fetus during pregnancy can affect the outcome of a pregnancy. Antineoplastic agents are mutagenic and teratogenic, so the potential effects of exposure on reproduction are of concern to the workers who handle them. This study investigates pregnancy loss associated with occupational exposures to antineoplastic drugs by comparing rates of spontaneous abortion and stillbirths for pregnancies without antineoplastic exposure and exposed pregnancies in which the pregnant woman or the father handled antineoplastic agents either before or during the pregnancy. A total of 7094 pregnancies of 2976 pharmacy and nursing staff were examined. After age during pregnancy, prior gravidity, maternal smoking during the pregnancy, and occurrence of a spontaneous abortion or stillbirth in a prior pregnancy were controlled for, exposure of the mother to or the handling of antineoplastic agents during the pregnancy was associated with a significantly increased risk of spontaneous abortion (odds ratio = 1.5; 95% confidence interval, 1.2 to 1.8) and combined risk of spontaneous abortion and stillbirth (odds ratio = 1.4; 95% confidence interval, 1.2 to 1.7) but not stillbirth alone. Among the wives of exposed men, too few stillbirths occurred to allow analysis. However, for spontaneous abortion and any loss, the patterns of increased risk were similar to those seen for women, although the odds ratios were not statistically significant.     

Reproductive male-mediated risk: Spontaneous abortion among wives of pesticide applicators

This study was conducted among 32 pesticide applicators occupationally exposed to pesticides to determine whether paternal exposure is associated with an increased risk of spontaneous abortion. The ratio of abortion was compared between applicators and a group of 51 food retailers (control population). The ratio of abortions/pregnancies for applicators was 0.27 and for retailers 0.07. OR for spontaneous abortion adjusted for age of wife and smoking of parents is 3.8 times greater than for the control population in the multiple logistic regression model and 7.6 times with interaction effects model.     

Paternal occupational lead exposure and spontaneous abortion

A case-referent study was conducted on whether occupational exposure of men to inorganic lead is related to spontaneous abortion in their wives. The men were biologically monitored for lead exposure. The cases (213 spontaneous abortions) and referents (300 births) were identified from medical registers. Lead exposure was assessed with blood lead (PbB) measurements and data obtained from a questionnaire. The results did not show a statistically significant relationship between spontaneous abortion and paternal lead exposure among all the study subjects. A significant increase was observed in the risk of those women whose husbands had been monitored (PbB greater than or equal to 1.5 mumol/l) during or close to the time of spermatogenesis. The association between lead exposure and spontaneous abortion was modified also by the age of the wife and paternal alcohol use. The findings suggest that there may be an association between paternal lead exposure and the risk of spontaneous abortion.     

Spontaneous abortion, sex ratio, and paternal occupational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

There is conflicting research regarding an association between fetal death and paternal exposure to Agent Orange, a phenoxy herbicide widely used in Vietnam that was contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Men who worked in the U.S. factories that produced Agent Orange were exposed to TCDD at levels hundreds of times higher than TCDD levels in the general population. Wives of TCDD-exposed chemical workers and wives of nonexposed neighborhood referents were interviewed to determine reproductive history. Paternal serum TCDD level at time of conception was estimated for each pregnancy using serum samples taken in 1987. Estimated TCDD levels of workers during or after exposure were high (median, 254 ppt; range, 3-16,340 ppt) compared to referent levels (median, 6 ppt; range, 2-19 ppt). No association between paternal TCDD level at the time of conception and spontaneous abortion was observed among pregnancies fathered by workers with TCDD levels of < 20 ppt [odds ratio (OR) = 0.77; 95% confidence interval (CI), 0.48-1.22], 20 to < 255 ppt (OR = 0.81; 95% CI, 0.40-1.63), 255 to < 1,120, (OR = 0.69; 95% CI, 0.30-1.58), and >or= 1,120 ppt (OR = 0.95; 95% CI, 0.42-2.17) compared to pregnancies fathered by referents. The sex ratio [males/(males + females)] of offspring also did not differ by TCDD exposure (0.53 and 0.54 among workers and referents, respectively). We did not find an association between paternal serum TCDD level and spontaneous abortion or sex ratio of offspring in this population. The estimated TCDD levels in this exposed worker population were much higher than in other studies, providing additional evidence that paternal TCDD exposure does not increase the risk of spontaneous abortion at levels above those observed in the general population. The study could not evaluate the effect of father's childhood or prenatal TCDD exposure on subsequent sex ratio.     

Association of petrochemical exposure with spontaneous abortion

OBJECTIVES: To assess the association between petrochemical exposure and spontaneous abortion, a retrospective epidemiological study in a large petrochemical complex in Beijing, China was conducted. METHODS: Plant employment records identified 3105 women who were married, were 20-44 years of age, and had never smoked. Of those, 3070 women (98.8%) reported at least one pregnancy. From this group, 2853 (93%) of the women participated in the study. According to their plant employment record, about 57% of these women workers reported occupational exposure to petrochemicals during the first trimester of their pregnancy. Trained interviewers administered a standardised questionnaire to this group of women and their husbands, collecting information on reproductive history, pregnancy outcomes, employment history, occupational exposure, smoking habits, alcohol consumption, indoor air pollution, and demographic variables. The results from the womens' first pregnancies were analysed. RESULTS: There was a significantly increased risk of spontaneous abortion for women working in all of the production plants with frequent exposure to petrochemicals (8.8%; range of 5.8%-9.8%) compared with those working in nonchemical plants (2.2%; range of 0.0%-7.1%). Also, when a comparison was made between exposed and non-exposed groups within each plant, exposure to petrochemicals was consistently associated with an increased risk of spontaneous abortion. The overall odds ratio (OR) was 2.7 (95% confidence interval (95% CI) 1.8 to 3.9) after adjusting for potential confounders. When the analysis was performed with the exposure information obtained from the women' interview responses for (self reported) exposures, the estimated OR for spontaneous abortions was 2.9 (95% CI 2.0 to 4.0). The analysis was repeated by excluding those 452 women who provided inconsistent reports between recalled exposure and work history, and a comparable risk of spontaneous abortion (OR 2.9; 95% CI 2.0 to 4.4) was found. In analyses for exposure to specific chemicals, an increased risk of spontaneous abortion was found with exposure to most chemicals, and the results for benzene (OR 2.5; 95% CI 1.7 to 3.7), gasoline (OR 1.8; 95% CI 1.1 to 2.9), and hydrogen sulphide (OR 2.3; 95% CI 1.2 to 4.4) were significant. CONCLUSION: An increased risk of spontaneous abortion was found associated with the exposure to petrochemicals, including benzene, gasoline, and hydrogen sulphide.

 

     

Spontaneous abortion and maternal work in greenhouses

BACKGROUND: A positive association between maternal occupational exposure to pesticide and spontaneous abortion has been reported in some studies. Work in greenhouses may imply exposure of pregnant women to pesticides continuously and at elevated level. METHODS: A total of 717 women working in greenhouses provided information on 973 pregnancies, including 110 spontaneous abortions. These pregnancies were classified as exposed or not exposed according to maternal occupation, re-entry activities and application of pesticides in greenhouses during at least 1 month in the first trimester of pregnancy. The ORs for spontaneous abortion were estimated through a generalised estimate equations model for all orders of pregnancy together, and through a logistic regression model limited to first pregnancies. RESULTS: Increased risks of spontaneous abortion were found for maternal re-entry activities within 24 hr after pesticides were applied (all orders of pregnancy: OR 3.2, 95% CI 1.3-7.7; first pregnancies: OR 3.8, 95% CI 1.0-13.9) and for those who applied pesticides (all orders of pregnancy: OR 2.6, 95% CI 1.0-6.6; first pregnancies: OR 3.7, 95% CI 0.7-20,6) CONCLUSIONS: The observed results support the hypothesis of an association between maternal work in greenhouses and spontaneous abortion. The main limitations of the study are lack of information on the specific chemicals used and the small number of pregnancies heavily exposed to pesticides.     

夫妇双方混苯暴露妊娠过程和妊娠结局的影响

目的：研究夫妇双方混苯暴露对妊娠过程和妊娠结局的影响。方法：应用回顾性队列研究方法对某石化企业女工的妊娠过程向妊娠结局进行了分析。结果：孕期浮肿、孕期贫血、自然流产和出生缺陷的发生率以双方暴露组最高，而双方皆不接触组最低，有显性差异（P＜0．05）。结论：丈夫也接触混苯可加重妊娠并发症及不良妊娠结局的发生。     

Occupational exposure to ethylene oxide during pregnancy and association with adverse reproductive outcomes

Objective To investigate the association between exposure to ethylene oxide during pregnancy and adverse reproductive outcomes. Methods Singleton pregnancies were analysed that: (1) had occurred in women working at the time of the study (2004) in hospital sterilising units using ethylene oxide in Gauteng province, South Africa; (2) was the last recognised pregnancy of these women after the 1 January 1992; and (3) this last recorded pregnancy had occurred while the mother was employed. An adverse reproductive outcome was defined as the occurrence of a spontaneous abortion, still birth or pregnancy loss (combined abortion + still birth). Information on the evolution and outcome of the pregnancy was gathered from the mother using a questionnaire. Information on exposure to ethylene oxide during pregnancy was obtained from three sources, namely walk-through surveys, questionnaire-collected data and measurements of the levels of ethylene oxide in sterilising units at the time of the study (personal and static sampling). Results The study enrolled 69% of the hospitals in Gauteng using ethylene oxide to sterilise medical equipment. The participation rate for women employed in these sterilising units was 97%, and the study population consisted of 98 singleton pregnancies. Measurements of ethylene oxide showed that operators of sterilisers were still potentially over-exposed. There was a significantly increased risk of spontaneous abortion (POR = 20.8, 95% CI = 2.1–199) and pregnancy loss (POR = 8.6, 95% CI = 1.8–43.7) for pregnancies highly exposed to ethylene oxide compared to low exposed pregnancies. No associations were found between exposure to ethylene oxide and stillbirth. Conclusions An increased risk of spontaneous abortion and pregnancy loss was found to be associated with exposure to ethylene oxide during pregnancy.     

Exposure to phenoxy herbicides and the risk of spontaneous abortion.

The Ontario Farm Family Health Study was designed to assess retrospectively the potential adverse effects of exposure to pesticides on pregnancy. Information on the health and life style of approximately 2,000 farm couples, as well as a history of use of pesticides on the farm, was collected by questionnaire. This analysis focuses on pre- and postconception exposure to phenoxy herbicides and the risk of spontaneous abortion using the complete (to date) pregnancy history for each woman. Preconception exposure (from 3 months before conception to the month of conception) was weakly associated with the risk of spontaneous abortion at <20 weeks' gestation [adjusted odds ratio (OR) = 1.1; 95% confidence interval (CI) = 0.6-1.9]. When the analyses were restricted to spontaneous abortions of <12 weeks, the risk was more than doubled (adjusted OR = 2.5; 95% CI = 1.0-6.4), but the results were sensitive to the cutpoint used. If the husband did not normally wear protective equipment during application, the crude OR for early spontaneous abortions was 5.0 (95% CI = 0.7-36.2). Exposure to phenoxy herbicides during the first trimester was generally not associated with increased risk of spontaneous abortion. The results suggest a possible role of preconception (possibly paternal) exposures to phenoxy herbicides in the risk of early spontaneous abortions.     

Paternal exposure to lead and infertility

To assess whether paternal exposure to lead is associated with infertility, we performed a register-based study among married men biologically monitored for exposure to inorganic lead. We obtained information about the marriages and the wives of the men from the Finnish Central Population Register. Data on pregnancies were obtained from medical records. Paternal exposure to lead was assessed on the basis of blood lead measurements. We estimated the risk of infertility, defined as nonoccurrence of a marital pregnancy, by applying binomial regression. For the blood lead categories of 0.5-0.9, 1.0-1.4, 1.5-1.9, 2.0-2.4, and > or =2.5 micromol/L the relative risk of infertility, compared with the risk in the lowest exposure category (<0.5 micromol/L), was 1.27 (95% confidence interval 1.08-1.51), 1.35 (1.12-1.63), 1.37 (1.08-1.72), 1.50 (1.08-2.02), and 1.90 (1.30-2.59), respectively. The findings support the hypothesis that paternal exposure to lead increases the risk of infertility at low occupational exposure levels. We applied proportional hazards regression to the analysis of pregnancy delay. A delay was observed among the wives of men exposed to lead. Exposure to lead was not clearly associated with delayed pregnancy, however, when the analysis was restricted to couples with at least one pregnancy. This finding suggests that the restriction of the study on time to pregnancy to fertile couples may introduce a bias toward no association.     

Induced abortion and spontaneous fetal loss in subsequent pregnancies.

The effect of induced abortion on spontaneous pregnancy loss in subsequent pregnancies was studied based on 3,416 pairs of matched data in a follow-up investigation. Pregnancy outcome was examined also in relation to abortion procedure, gestation length at time of abortion, and number of previous abortions. In general there was no significant association between prior induced abortion and risks of pregnancy loss with the relative risks of 1.10, 0.88, and 0.81 for the first to third trimester respectively. A slight increase of first-trimester spontaneous loss was noted with the D&C/Suction procedure and early induced abortion (less than 9 weeks). The D&C procedure was associated with non-significant increase of second-trimester loss with the relative risk of 1.59.     

Prevention of recurrent spontaneous abortions by leukocyte transfusions.

One hundred and thirty-nine couples referred because of recurrent abortions with no obvious cause were assessed for genetic similarity using the HLA major histocompatibility system. Comparison with 103 fertile control couples demonstrated that a much higher proportion of couples in the abortion group shared two or more HLA antigens. Using this criterion, 44 wives out of the 139 couples referred, when compared with a child-bearing group, appeared to share a greater than expected number of histocompatibility antigens and were therefore considered suitable for treatment. Twenty-eight wives have received treatment with white cell infusions from erythrocyte-compatible donors and so far they have delivered 17 babies plus 2 second babies. Another 3 wives are pregnant beyond their previous dates for abortions (1 first and 2 second pregnancies). There have been 5 failures (4 first pregnancy and 1 second pregnancy); one of these was treated a second time and has now successfully delivered. Seven couples are awaiting conception. Of the patients who have become pregnant, 81.5% have had successful deliveries. No adverse transfusion reactions have been observed.