Acute and recent air pollution exposure and cardiovascular events at labour and delivery.

OBJECTIVE: To study the relationship between acute air pollution exposure and cardiovascular events during labour/delivery. METHODS: The Consortium on Safe Labor (2002-2008), an observational US cohort with 223,502 singleton deliveries provided electronic medical records. Air pollution exposure was estimated by modified Community Multiscale Air Quality models. Cardiovascular events (cardiac failure/arrest, stroke, myocardial infarcts and other events) were recorded in the hospital discharge records for 687 pregnancies (0.3%). Logistic regression with generalised estimating equations estimated the relationship between cardiovascular events and daily air pollutant levels for delivery day and the 7 days preceding delivery. RESULTS: Increased odds of cardiovascular events were observed for each IQR increase in exposure to nitric oxides at 5 and 6 days prior to delivery (OR=1.17, 99% CI 1.04 to 1.30 and OR=1.15, 1.03 to 1.28, respectively). High exposure to toxic air pollution species such as ethylbenzene (OR=1.50, 1.08 to 2.09), m-xylene (OR=1.54, 1.11 to 2.13), o-xylene (OR=1.51, 1.09 to 2.09), p-xylene (OR=1.43, 1.03 to 1.99) and toluene (OR=1.42, 1.02 to 1.97) at 5 days prior to delivery were also associated with cardiovascular events. Decreased odds of events were observed with exposure to ozone. CONCLUSIONS: Air pollution in the days prior to delivery, especially nitrogen oxides and some toxic air pollution species, was associated with increased risk of cardiovascular events during the labour/delivery admission.

Does maternal asthma contribute to racial/ethnic disparities in obstetrical and neonatal complications?

PURPOSE: To examine whether maternal asthma contributes to racial/ethnic differences in obstetrical and neonatal complications. METHODS: Data on white (n = 110,603), black (n = 50,284), and Hispanic (n = 38,831) singleton deliveries came from the Consortium on Safe Labor. Multilevel logistic regression models, with an interaction term for asthma and race/ethnicity, estimated within-group adjusted odds ratios (aORs) for gestational diabetes, gestational hypertension, pre-eclampsia, placental abruption, premature rupture of membranes, preterm delivery, maternal hemorrhage, neonatal intensive care unit admissions, small for gestational age, apnea, respiratory distress syndrome, transient tachypnea of the newborn, anemia, and hyperbilirubinemia after adjustment for clinical and demographic confounders. Nonasthmatics of the same racial/ethnic group were the reference group. RESULTS: Compared with nonasthmatics, white asthmatics had increased odds of pre-eclampsia (aOR, 1.28; 95% confidence interval [CI], 1.15-1.43) and maternal hemorrhage (aOR, 1.14; 95% CI, 1.04-1.23). White and Hispanic infants were more likely to have neonatal intensive care unit admissions (aOR, 1.19; 95% CI, 1.11-1.28; aOR, 1.16; 95% CI, 1.02-1.32, respectively) and be small for gestational age (aOR, 1.11; 95% CI, 1.02-1.20; aOR, 1.26; 95% CI, 1.10-1.44, respectively), and Hispanic infants were more likely to have apnea (aOR, 1.32; 95% CI, 1.02-1.69). CONCLUSIONS: Maternal asthma did not affect most obstetrical and neonatal complication risks within racial/ethnic groups. Despite their increased risk for both asthma and many complications, our findings for black women were null. Asthma did not contribute to racial/ethnic disparities in complications.