Associations of Preeclampsia with Expiratory Airflows in School-Age Children Born Either at <28 Weeks or Weighing <1000 g.

Abstract

To assess whether preeclampsia was associated with expiratory airflow at school-age in children born either extremely preterm (<28 weeks of gestation) or extremely low birthweight (ELBW; <1000 g birth weight). Participants comprised 3 cohorts of children born extremely preterm/ELBW in the state of Victoria, Australia, in 1991-1992, 1997, or 2005. Expiratory airflows were measured at age 8 years, and results converted to z scores. Data were compared between those exposed to preeclampsia with those unexposed to preeclampsia; analyses were then adjusted for confounding perinatal variables. Analyses were repeated within subgroups of extremely preterm only and ELBW only. Respiratory data were available for 544 of 717 (76%) survivors, of whom 95 (17%) had been exposed to preeclampsia. On univariable analysis, those exposed to preeclampsia had better z scores for flows for the forced expired volume in 1 second (zFEV₁) (mean difference 0.29, 95% CI 0.04-0.53; P = .022) and zFEV₁/forced vital capacity (mean difference 0.33, 95% CI 0.04-0.61; P = .025); the difference persisted for zFEV₁ after adjustment for confounding perinatal variables. Analyses confined to those born extremely preterm revealed little evidence for associations between preeclampsia and airflow. In analyses confined to those born ELBW, preeclampsia was associated with better zFEV₁, which persisted after adjustment (mean difference 0.33, 95% CI 0.04-0.63; P = .025). Exposure to maternal preeclampsia was not associated with worse expiratory airflow in children born extremely preterm/ELBW; in fact, some airflows were better.