Potential parental exposure to pesticides and limb reduction defects.

OBJECTIVES: The goal of the study was to examine the effects of the potential pesticide exposure of parents on the risk of limb reduction defects in their offspring. METHODS: A case-referent study was conducted utilizing New York State Congenital Malformation Register data. Persons with limb reduction defects and referents were compared in terms of parental occupations and residence counties. Parental occupations and industries reported on birth certificates were qualitatively rated by industrial hygienists to estimate potential pesticide (list four groups) exposures. Residential exposures were estimated from agricultural census data according to county of residence. RESULTS: Neither parental exposure to pesticides [odds ratio (OR) 0.9, 95% confidence interval (95% CI) 0.6-1.4] nor farming occupation (OR 1.1, 95% CI 0.5-2.7) had an effect on the risk of total limb reduction defects. Those persons with limb reduction defects who had additional defects showed weak but consistent elevated risks in relation to parental occupational pesticide exposure. However, isolated cases of limb reduction defects were negatively related to these exposures. Residence in a farming or high pesticide use county was not associated with any type of limb reduction defect. CONCLUSIONS: Cases of limb reduction defect with additional malformations appear to be associated with parental occupational pesticide exposure. Improving exposure classifications and subdividing the limb reduction defects by types in the analyses are suggested for future research.

Evaluation of congenital limb reduction defects in upstate New York.

Limb reduction defects (LRD), reported to the Congenital Malformations Registry in upstate New York between 1983-1987, were investigated in terms of LRD classification, parental demographics, and LRD characteristics. After excluding LRD with chromosome abnormalities, we followed guidelines developed by the European Congenital Anomaly Surveillance Consortium (EUROCAT) to classify 271 LRD into six groups based on similar patterns of embryological failure. The descriptive analysis indicated a prevalence of 0.45 per 1,000 births (stable over 5 years) for LRD diagnosed during the first 2 years of life. Among 271 LRD cases, 95 were classified as terminal transverse (35.1%), 71 as split limbs (26.2%), 36 as preaxial (13.3%), 32 as postaxial (11.8%), 26 as intercalary (9.6%), and 11 as multiple types (4.1%). In cases with multiple limb involvement (28.4%), two thirds had the same type of LRD in each limb. The multiple types and preaxial groups showed the most distinctive characteristics: they had the highest frequency of suspected syndromes, other birth defects, and syndactyly compared to the other LRD. There were no significant differences in the distribution of demographic variables among different LRD types. Consideration of the incidence and characteristics of LRD by classifying them into these distinct subgroups may be useful for evaluating possible mechanisms of malformation.

Comparison of mother's occupation and industry from the birth certificate and a self-administered questionnaire.

Maternal occupations recorded on birth certificates are a potential data source for evaluation of reproductive hazards, but may not accurately identify jobs held during the sensitive first trimester. Mothers' occupation and industry during 1 month before and 3 months after conception were reported on 1,760 mailed questionnaires. These were compared to mothers' most recent occupation and industry recorded on birth certificates. Overall, 72% of occupations and 77% of industries reported on the birth certificate agreed with that recorded on the questionnaire. Agreement was similar for mothers of normal and malformed infants. Among those that did not agree, 344 (75%) disagreed on the mother's employment status during the periconceptional period, rather than the actual occupation. For surveillance and hypothesis-generation using birth certificate data, it is important to obtain a correct description of whether the mother held a job outside the home during sensitive periods of her pregnancy.