Maternal ethnicity and pre-eclampsia in New York City, 1995-2003.

Studies on ethnic differences in the risk of pre-eclampsia are limited. We linked birth records for 902,460 singleton births for the period 1995-2003 in New York City with hospital discharge data to evaluate the association between ethnicity and the risk of pre-eclampsia and compare risks between US-born and foreign-born women. Logistic regression models adjusted for maternal age, maternal education, parity, self-reported pre-pregnancy maternal weight, smoking during pregnancy and year of delivery were used to compare each ethnic group with non-Hispanic White women. The prevalence of pre-eclampsia in this study population was 3.2%. Among the major ethnic groups considered in our study, East Asian women had the lowest risk of pre-eclampsia (1.4%) and Mexican women had the highest risk (5.0%). Compared with non-Hispanic White women, there was a slightly decreased risk for East Asian women (adjusted OR = 0.8, [95% CI 0.7, 0.8]), similar risk for North African women (adjusted OR = 1.1, [95% CI 0.9, 1.3]), and increased risk for all other major ethnic groups (adjusted ORs: 1.3, 2.9), with the highest risk for Mexican women (adjusted OR = 2.9, [95% CI 2.7, 3.1]). No difference in risks was observed for US- vs. foreign-born women with the exception that foreign-born South-East Asian and Pacific Islanders had an increased risk of pre-eclampsia (adjusted OR = 1.8, [95% CI 1.0, 3.1]) relative to those born in the US. We concluded that there was ethnic heterogeneity in the development of pre-eclampsia among women in New York City and that Asian subgroups should be examined separately in future studies on ethnicity. Our results should contribute to screening for pre-eclampsia taking ethnic variation into account, and may help to suggest leads for the study of the aetiology of the condition.