Impact on pregnancy outcomes of exposure to military stress during the first or second trimester as compared with the third trimester

Objective: To compare pregnancy outcomes after exposure to military stress in different trimesters of pregnancy. Methods: A retrospective study of medical records of deliveries in the Wolfson (WMC) and Barzilai (BMC) medical centers in Israel between July 2014 and April 2015. All parturients were exposed to military stress for 51 days during pregnancy. Pregnancy outcomes were compared between those exposed to military stress in the first or second trimester, and those exposed in the third trimester. Outcomes were also compared between WMC (a new-onset military stress exposure area) and BMC (a chronic military stress exposure area). Results: At WMC, women exposed in the first or second trimester (n=2657) had a higher rate of preterm delivery (<37 weeks) as compared with those exposed in the third trimester (n=2037; 214 [8.1%] vs 121 [5.9%]; P=0.005). At BMC, women exposed in the first or second trimester (n=2208) had a tendency toward lower rates of diabetes mellitus (P=0.055) and macrosomia [103 (4.7%) vs 84 (6.3%); P=0.037], as compared with those exposed in the third trimester (n=1337). Conclusion: Exposure to military stress during pregnancy had different impacts on pregnancy outcomes, depending on the time of exposure and whether continuous exposure to stress occurred.