698 Differences in timing of delivery among rural women in America

Abstract

National safety and quality efforts aim to reduce unindicated deliveries prior to 39 weeks. Studies show compliance with this effort nationally; however, little is known if differences exist for rural women. We conducted a retrospective cohort study using 2015 national vital statistics birth certificate data. Maternal county of residence was identified and women residing in counties <50,000 were identified as rural and all other women as non-rural. We included all singleton, non-anomalous pregnancies delivering between 36-41 weeks. We compared differences in the proportion of deliveries occurring at each week. We repeated our analysis excluding hypertensive disease and diabetes to create a low risk population. We further stratified by maternal race/ethnicity. We used bivariate tests for comparisons. We identified 3,407,249 women of which 385,920 (11.3%) were rural. Overall, rural women were more likely to deliver at 36 weeks (3.7% vs 3.3%), 37 weeks (9.3% vs 8.8%), 38 weeks (17.4% vs 17.0%), and 39 weeks (43.0% vs 40.4%) than non-rural women, and less likely to deliver at 40 weeks (21.0% vs 23.3%) and 41 weeks (5.6% vs 7.2%) than non-rural women (p<0.001). In the low risk cohort, 3,405,514 women were included of which 385,636 (11.3%) were rural. The distribution of deliveries by week was the same as in the overall cohort. Figure 1 When stratified by race/ethnicity among low risk women, these trends persisted with rural women delivering in higher proportions at 36-38 weeks. Overall, rural Black women had the highest proportion of deliveries occurring at 36 (5.0%), 37 (11.2%), and 38 (20.4%) weeks and the lowest proportion of deliveries at 40 (16.8%) and 41 (3.6%) weeks. Figure 2 Differences in the distribution of deliveries exist between rural and non-rural women and by race/ethnicity. It is unclear if these differences are the result of medical necessity, differences in timing of spontaneous delivery, or variance in application of the 39 week rule. Additional study to examine the source of these differences and any associated adverse effect is warranted.View Large Image Figure ViewerDownload Hi-res image Download (PPT)