Helena Taskinen

Spontaneous Abortions Among Finnish Flight Attendants

We conducted a retrospective cohort study to investigate whether work as a cabin attendant is related to an increased risk for spontaneous abortion. Data on female cabin crew members were linked to medical records on pregnancies. There were 1751 eligible pregnancies for the final analysis. Flight attendants who worked during early pregnancy had a slightly elevated risk of spontaneous abortion, as compared with attendants who were pregnant outside a time span of active flying (odds ratio [OR] = 1.3; 95% confidence interval [CI], 0.9 to 1.8). During the earliest years of the study period (1973 through 1977), the risk seemed to be decreased (OR = 0.4; 95% CI, 0.2 to 1.1), whereas during the later years (1978 through 1994) the risk was increased (OR = 1.6; 95% CI, 1.1 to 2.4). The results are in agreement with earlier studies, showing suggestive evidence of a slightly increased risk of spontaneous abortion among female cabin crew members.

Parvovirus B19 Infection in Fetal Deaths

BACKGROUND Parvovirus B19 infection during pregnancy can lead to nonimmune fetal hydrops, miscarriage, and intrauterine fetal death (IUFD). Some studies have suggested that parvovirus B19 infection may surprisingly often result in nonhydropic fetal death during the third trimester, in the absence of maternal serological evidence of acute infection. This study was conducted to investigate the prevalence of parvovirus B19 DNA among fetuses from miscarriages and IUFDs. METHODS We retrospectively studied 535 unborn fetuses, including 120 fetuses from miscarriages and 169 from IUFDs. The control fetuses were 246 fetuses from induced abortions. All fetuses were autopsied from July 1992 through December 1995 and from January 2003 through December 2005 in Helsinki, Finland. The period included a major epidemic of parvovirus B19 infection in 1993. Formalin-fixed, paraffin-embedded fetal tissues were studied with use of a highly sensitive and specific PCR that was capable of detecting all 3 parvovirus B19 genotypes and by histologic examination. In addition, maternal parvovirus B19 serological status was determined. RESULTS Parvovirus B19 DNA was detected in 5 fetuses with gestational ages of 14, 22, 23, 30, and 39 weeks; these included fetuses from 4 (2.4%) of the 169 IUFDs and 1 (0.8%) of the 120 miscarriages. During the epidemic year 1993, the prevalence of parvovirus B19 DNA-positive fetal deaths was 6 times the prevalence during nonepidemic years. All 5 mothers of the parvovirus B19 DNA-positive fetuses had serological signs of acute parvovirus B19 infection close to the time of fetal death. The only nonhydropic fetus was full-term. CONCLUSIONS Our findings indicate that the prevalence of parvovirus B19 infection among fetuses from IUFDs is low. In particular, our findings did not verify the claimed high prevalence of third-trimester nonhydropic IUFDs associated with parvovirus B19.

Occupational exposure in dentistry and miscarriage.

Background: Information on the reproductive effects of chemical exposures in dental work is sparse or inconsistent. Aim: To investigate whether dental workers exposed to acrylate compounds, mercury amalgam, solvents or disinfectants are at an increased risk of miscarriage. Methods: The study was conducted among women dental workers and a comparison group of workers occupationally unexposed to dental restorative materials. Information on pregnancies was obtained from national registers and outpatient units of hospitals. Data on occupational exposure were obtained using postal questionnaires. The final study population included 222 cases of miscarriage and 498 controls (births). An occupational hygienist assessed exposure to acrylate compounds, disinfectants and solvents. Exposure to other agents was assessed on the basis of the questionnaire data. Odds ratios (ORs) and confidence intervals (CIs) were estimated using conditional logistic regression. Results: The ORs adjusted for confounding factors were increased for moderate-exposure and high-exposure categories of mercury amalgam (OR 2.0, 95% CI 1.0 to 4.1 and OR 1.3, 95% CI 0.6 to 2.5, respectively). The risk was slightly increased for the highest-exposure category of 2-hydroxyethylmethacrylate (OR 1.4, 95% CI 0.7 to 2.6) and polymethylmethacrylate dust (OR 1.4, 95% CI 0.8 to 2.4). A slightly increased risk was also detected for likely exposure to organic solvents (OR 1.4, 95% CI 0.8 to 2.3) and disinfectants (OR 1.5, 95% CI 0.9 to 2.7). Conclusions: No strong association or consistent dose–response relationship was observed between exposure to chemical agents in dental work and the risk of miscarriage. A slightly increased risk was found for exposure to mercury amalgam, some acrylate compounds, solvents and disinfectants. These findings indicate that the possibility of a weak association between exposure to these agents and an increased risk of miscarriage cannot be excluded.

Newly discovered KI, WU, and Merkel cell polyomaviruses: No evidence of mother-to-fetus transmission

BackgroundThree* human polyomaviruses have been discovered recently, KIPyV, WUPyV and MCPyV. These viruses appear to circulate ubiquitously; however, their clinical significance beyond Merkel cell carcinoma is almost completely unknown. In particular, nothing is known about their preponderance in vertical transmission. The aim of this study was to investigate the frequency of fetal infections by these viruses. We sought the three by PCR, and MCPyV also by real-time quantitative PCR (qPCR), from 535 fetal autopsy samples (heart, liver, placenta) from intrauterine fetal deaths (IUFDs) (N = 169), miscarriages (120) or induced abortions (246). We also measured the MCPyV IgG antibodies in the corresponding maternal sera (N = 462) mostly from the first trimester.ResultsNo sample showed KIPyV or WUPyV DNA. Interestingly, one placenta was reproducibly PCR positive for MCPyV. Among the 462 corresponding pregnant women, 212 (45.9%) were MCPyV IgG seropositive.ConclusionsOur data suggest that none of the three emerging polyomaviruses often cause miscarriages or IUFDs, nor are they transmitted to fetuses. Yet, more than half the expectant mothers were susceptible to infection by the MCPyV.

Absence of human bocavirus from deceased fetuses and their mothers

BACKGROUND The human bocavirus (HBoV), a newly discovered parvovirus, is closely related to the bovine parvovirus and the canine minute virus, which are known to cause adverse pregnancy outcomes. Another human parvovirus, B19, can lead to fetal hydrops, miscarriage and intrauterine fetal death (IUFD). OBJECTIVES To determine the prevalence of HBoV DNA in aborted fetuses and IUFDs. The HBoV serology of the mothers was also studied. STUDY DESIGN We retrospectively studied all available fetuses (N=535) autopsied during 7/1992-12/1995, and 1/2003-12/2005 in Helsinki, Finland. All available formalin-fixed paraffin-embedded fetal tissues - placenta, heart and liver - of 120 miscarriages, 169 IUFDs, and 246 induced abortions were studied by quantitative PCR. We also measured the HBoV IgM and IgG antibodies in the corresponding maternal sera (N=462) mostly of the first trimester. The IgM-positive sera underwent HBoV PCR. RESULTS None of the fetal tissues harbored HBoV DNA. A total of 97% (448/462) of the mothers were positive for IgG antibodies to HBoV, while only 0.9% (4/462) exhibited HBoV-specific IgM antibodies without viremia or respiratory symptoms. One IgM-positive mother had an unexplained fetal loss. CONCLUSIONS We did not find HBoV DNA in any of the deceased fetuses. Almost all pregnant women were HBoV-IgG positive.

Nordic criteria for reproductive toxicity

Scientific criteria for assessment of the reproductive toxicity of chemicals have been proposed by a Nordic group of experts and regulatory representatives. The criteria take into account the results of clinical studies as well as of experimental research. The criteria should be useful in, for example, product control and labeling and planning of a safe work environment. The proposed Nordic criteria and examples of the assessment of the reproductive toxicity of some chemicals are presented.

Occupational exposure to chemicals and reproductive health

Publisher Summary This chapter describes the epidemiological studies on the reproductive and developmental effects of occupational exposure to chemical agents. Chemicals covered in this chapter are organic solvents, metals, CO, pesticides, anesthetic gases, antineoplastic agents and some other drugs. An increased risk of miscarriage has been observed in industrial populations usually exposed to high levels of solvents. These include employees in manufacturing, dry cleaning, painting, shoe, pharmaceutical, audio speaker, semiconductor and laboratory industries. Occupational health personnel utilize the classification and the warning signs in the risk assessment, but often toxicological consultations are also needed. The recognition of a chemical as a reproductive or developmental toxicant is based on experimental studies or human studies, mainly epidemiological but sometimes case series-type studies. Epidemiological studies provide information on possible effects of occupational exposure to working populations. The reproductive toxicity of some metals has been known for a long time, but not all common metals in occupational use have been thoroughly investigated in epidemiological studies. Here, the main findings are summarized. Carbon monoxide is transported through the placenta; in the fetus, the concentration of blood carboxyhemoglobin is 10–15% higher than in the mothers blood. Occupational exposure to antineoplastic drugs has been associated with menstrual dysfunction, infertility and adverse pregnancy outcome.

Increased risk of human parvovirus B19 infection in day-care employees: a cohort study among pregnant workers during an epidemic in Finland

Background Human parvovirus B19 (B19V) infection during early pregnancy increases the risk of miscarriage. Studies have inconsistently shown an elevated risk of infection among women with occupational contacts with children. Methodological differences, particularly in defining occupational exposure and in the type of reference group, may explain the conflicting findings. Methods This cohort study compared B19V infections in pregnant day-care employees and healthcare professionals during a B19V epidemic in Finland. Women were identified from the files of nationwide trade unions and the National Supervisory Authority for Welfare and Health. Early-pregnancy maternal B19V IgG was analysed in 3710 women, and infections were defined as seroconversions after analysing in parallel the available umbilical cord blood samples of the 847 seronegative mothers. Independently of the serological status, the actual employment during pregnancy was assessed using registered information on employment history. Results B19V infections were more common among day-care employees (22/331, 6.6%), than among those working in healthcare (12/326, 3.7%). The adjusted HRs of B19V infection, using proportional hazard regression, was 2.63 (95% CI 1.27 to 5.46) among all women and 5.59 (95% CI 1.40 to 22.4) among nulliparous women. Conclusions Day-care employees are at an increased risk of B19V infection, which warrants preventive measures.