Purpose: We evaluated whether the association of socioeconomic risk factors for trisomy 21 differed by type of maternal meiotic error.
Methods: We determined meiotic errors by DNA analysis for 150 trisomy 21 cases, and maternal lifetime exposures to low socioeconomic factors by questionnaire.
Results: Mothers of meiosis II cases were significantly more likely to be exposed to four low socioeconomic factors than mothers of meiosis I cases (odds ratio = 9.50; 95% confidence interval = 1.8-49.8).
Conclusion: Maternal lifetime exposure to poor socioeconomic environment is a risk factor for a trisomy 21, particularly if nondisjunction leads to a maternal meiosis II.