OBJECTIVEThis paper was to analyze the difference of exposure levels of the environmental risk factors on birth defects during peri-conceptional period between intended and unintended pregnancies, and to estimate the role of intended pregnancies in reducing exposure of environmental risk factors.

METHODSData used in this paper were from a retrospective survey of maternal women from 2002 through 2004 conducted in Wuxi city. The total number of women under study was 1628. Logistic regression model was employed to control women's childbearing age and education level for analysis of the role of intended pregnancies in reducing risk of unsafe use of medicine during pregnancy, exposure to toxic substance in working or living environments and unhealthy lifestyles.

RESULTSThe proportion of intended pregnancies was 73.2%. The proportion of intended pregnancies in urban women was slightly lower than that in rural women,and the proportion of intended pregnant women whose childbearing age was over 30 years old,was significantly higher than that whose childbearing age was under 30 years old. There were significant differences in exposure risks of unsafe use of medicine and some unhealthy lifestyles between the intended and the unintended. In the intended group, the proportions of taking the suspicious teratogenic drugs and staying up were 2.5% and 2.9% respectively, significantly lower than those in unintended group whose proportion were 6.0% and 5.5%. When compared with the unintended pregnant women, the exposure risk of taking the suspicious teratogenic drugs and staying up in intended pregnant women decreased by 60% and 50% respectively.

CONCLUSIONIntended pregnancies could significantly reduce the risk of taking the suspicious teratogenic drugs and unhealthy lifestyles. Reducing the incidence of unwanted pregnancy and increasing the proportion of intended pregnancies were both cost-effective methods for preventing birth defects.