Maternal nickel exposure and congenital musculoskeletal defects.

OBJECTIVE: To investigate whether women occupationally exposed to nickel in early pregnancy are at elevated risk of delivering a newborn with a malformation or deformation of the musculoskeletal system (ICD-10: Q65-Q79). METHODS: Data about the newborn, maternal occupation and workplace were obtained using the Kola Birth Register (KBR). Each record in the KBR was assigned a categorical nickel (Ni) exposure rating according to the occupation the delivering woman had at the time of becoming pregnant. This was achieved by using as a guideline the water-soluble Ni subfraction of the inhalable aerosol fraction obtained by personal monitoring for nickel- and copper-refinery workers or/and measured urinary-Ni concentrations. The reference population was delivering women from the source population with background exposure level. In total, the study population consisted of 22,965 births. RESULTS: Three hundred and four infants (13.3/1,000 births; 95% confidence interval (CI): 11.9-14.7) were diagnosed with isolated musculoskeletal defect(s) at birth. The adjusted odds ratio for the association between the maternal exposure to Ni and this outcome was 0.96 (95% CI: 0.76-1.21) per unit increase in exposure category. CONCLUSION: The incidence of defects in the musculoskeletal system at birth was high, especially for feet deformities, but we found no effect of maternal exposure to water-soluble Ni on the risk of delivering a newborn with a defect. However, the incidence among women working in the copper refinery was higher than in the other employment groups.

Pregnancy health and outcome in two cities in the Kola Peninsula, Northwestern Russia.

OBJECTIVES: The aims of the study were to compare the prevalence of selected maternal and lifestyle factors as well as the reproductive outcome of working women in two cities in Northwestern Russia (Moncegorsk and Apatity), and to assess the quality of pregnancy-outcome data obtained in an interview with registered information. STUDY DESIGN: A retrospective questionnaire study in an interview format. Women (n =1696) from selected workplaces in Apatity and Moncegorsk participated (85% of those available). Information was collected about past pregnancies, including information about the pregnancy outcome, newborn, occupation, health and life-style. RESULTS: The investigated groups had experienced 7,254 pregnancies in total, corresponding to 4.3 pregnancies on average per woman. In both groups, about one-half of the reported pregnancies were terminated, and three-quarters of the women had undergone an induced abortion. Spontaneous abortions had been experienced by 23% of the women in the Apatity group, which was higher than in the Moniegorsk group (16%). Previous spontaneous abortions appear more likely to be disclosed than induced abortions. The smoking prevalence was 37% in the Moncegorsk group and 24% in the Apatity group. Thirteen percent of all participants had been diagnosed with a pelvic inflammatory disease. CONCLUSIONS: Induced abortions were common in Northwestern Russia regardless of city of residency, and the majority of the abortions appear to have occurred after the women had their attainable or desired number of children. The proportion of pregnancies resulting in a spontaneous abortion was higher in the investigated group in Apatity than in Moncegorsk, which should be investigated further. This study also confirmed that smoking has become more widespread among women in the Kola Peninsula, as elsewhere in Russia.

Small-for-gestational-age newborns of female refinery workers exposed to nickel.

OBJECTIVES: It has not yet been established whether exposure to nickel (Ni) compounds may cause reproductive toxicity. The objective of this study was to investigate whether women employed under conditions of nickel exposure in early pregnancy were at elevated risk of delivering a newborn small-for-gestational-age (SGA). MATERIALS AND METHODS: A register-based study of a well defined population. Data on pregnancy outcome and maternal occupation were obtained from the Kola Birth Registry. Each birth record was assigned a Ni exposure rating category according to maternal occupation at the time of becoming pregnant. Nickel exposure assessment was based on determining the water-soluble Ni subfraction of respirable aerosol fraction obtained by personal monitoring, and/or on measurements of urine Ni concentration. The reference population were the delivering women with background exposure level. The study population consisted of 22 836 births (>27 weeks of gestation) and the SGA infants were defined as below the 10th percentile birth weight for gestational age in the source population. Multiple logistic regression was used to analyze the association of the outcome with the assigned exposure rating category. RESULTS: The adjusted odds ratio for Ni-exposed women for giving birth to an SGA newborn was 0.84 (95% CI: 0.75-0.93). CONCLUSIONS: We found no adverse effect of maternal occupational exposure to water-soluble Ni in the first part of pregnancy on the risk of delivering an SGA newborn without trisomy. The finding does not exclude a possibility that exposure throughout pregnancy might produce such an effect.

Genital malformations in newborns of female nickel-refinery workers.

OBJECTIVES: This study investigated whether pregnant women employed in nickel-exposed work areas are at elevated risk of delivering a newborn with a genital malformation. METHODS: In this register-based cohort study, data about pregnancy outcome and occupation were obtained using the Kola Birth Registry. Each record in the Registry was assigned a categorical nickel exposure rating according to the occupation the delivering woman had at the time of becoming pregnant, using, as guidelines, the water-soluble nickel subfraction of the inhalable aerosol fraction obtained by personal monitoring for nickel-refinery workers or the measured urinary nickel concentrations. The reference population comprised delivering women from Moncegorsk with a background exposure level. The association of the outcome with the assigned exposure ratings was analyzed in a logistic regression model, adjusted for parity, maternal malformation, exposure to solvents, and infection in early pregnancy. RESULTS: The odds ratio for nickel-exposed women delivering a newborn with a genital malformation was 0.81 [95% confidence interval (95% CI) 0.52-1.26], and that for an undescended testicle was 0.76 (95% CI 0.40-1.47). CONCLUSIONS: In this study no negative effect of maternal exposure to water-soluble nickel was found on the risk of delivering a newborn with malformations of the genital organs. The results should be interpreted with caution since there were few cases in the higher exposure groups. The findings do not exclude the possibility of an effect on the risk of other congenital malformations and adverse outcomes (including reduced fertility).