title: Role of race in the seasonality of deliveries with preeclampsia.
abstract: Preeclampsia is a disorder of pregnancy characterized by hypertension with proteinuria after twenty weeks gestation. The condition is an important cause of both maternal and infant mortality worldwide. One potential risk factor for preeclampsia that has been studied in a variety of countries and climates is time of the year of delivery. Several studies have reported a significant seasonality to preeclampsia, but their specific findings are contradictory. Interestingly, the places where much of this research occurred were comprised of populations whose race was fairly homogeneous. Further, a recent large scale study of preeclampsia in the United States separated out the women by race and reported a seasonality for white women, but not for black women. We performed a retrospective review of three years of hospital records for a medical center in Tulsa, Oklahoma, in order to search for evidence of a possible correlation between incidence of preeclamptic deliveries and month of the year. Our population was comprised of various ethnicities, but race was not included in the charts and could not be taken into consideration. Although the study was sufficiently powered, neither analysis of variance nor contingency table analysis revealed a significant seasonality of preeclamptic deliveries, (P=0.9489 and 0.9549, respectively). Given the reported contradictory findings for various homogeneous populations, the finding of differences of seasonality of preeclampsia between blacks and whites in a large US study, and the lack of evidence for seasonality of preeclampsia in our diverse sample study, we conclude that the seasonality of preeclampsia deliveries may be influenced by genetic differences related to race. Future research should focus on separating out study participants by racial and ethnic backgrounds. If another identifiable risk factor for this dangerous condition exists, even for only a particular subset of a population, its identification can help physicians to more quickly recognize and respond to the disorder.
authors.affiliation: Oklahoma State University Center for Health Sciences and College of Osteopathic Medicine and Surgery, Department of Obstetrics, 1111 W. 17th St. Tulsa, OK 74107, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Bullock
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Breese McCoy
authors.forename: Mark E
authors.initials: ME
authors.lastname: Payton
mesh_terms: D044383:Black People; D005260:Female; D006801:Humans; D036801:Parturition; D011225:Pre-Eclampsia / Q000208:ethnology* / Q000503:physiopathology; D011247:Pregnancy; D044465:White People