Interest of the trajectory method for the evaluation of outcomes after in utero drug exposure: example of anxiolytics and hypnotics

PURPOSE: The aim of this study was to examine the potential benefit to take into account duration and intensity of drug exposure using the recently published method based on individual drug trajectories. This approach was used to define profiles of exposure to anxiolytics/hypnotics during pregnancy and to evaluate the potential effect on newborn health.

METHODS: The study was performed in EFEMERIS database (54 918 mother-children pairs). An estimation of adaptation to extrauterine life was assessed using several criteria especially cardio-respiratory symptoms. A proxy variable called "neonatal pathology" was created. The occurrence of this event was studied using two approaches: The Standard Method comparing exposed and unexposed newborns, The Trajectory Method comparing the different profiles of exposure.

RESULTS: Around 5% of newborns (n = 2768) were identified to be exposed to anxiolytics or hypnotics during pregnancy. Using the Standard Method, 6.2% of exposed newborns developed a "neonatal pathology" against 4.8% of unexposed newborns (odds ratios [OR] = 0.9[0.8-1.2], p = 0.7). With the Trajectory Method taking into account evolution of exposure during pregnancy and treatment intensity, four profiles of pregnant women were identified. A significant difference in the rates of "neonatal pathologies" was observed between profiles (p = 0.0002). Newborns of the two profiles exposed in utero to high constant level of anxiolytics or hypnotics were more at risk of developing "neonatal pathology" than unexposed newborns (OR1 = 2.0 [1.0-3.9] and OR2 = 7.6 [2.8-20.5]).

CONCLUSIONS: The present study demonstrates the interest of this method based on individual drug trajectories for the evaluation of outcomes in pharmaco-epidemiological studies and more specifically during pregnancy. Copyright © 2017 John Wiley & Sons, Ltd.