OBJECTIVES: Adverse early-life experience may affect preterm delivery later in life through priming of stress response. We aim to investigate the links between out-of-home care (OHC) experience in childhood, as a proxy of severe adversities, on subsequent risk of preterm delivery. METHODS: A register-based national cohort of all women born in Sweden between 1973 and 1977 (N = 175 821) was crosslinked with information on these women's subsequent deliveries as recorded in the Swedish medical birth register. During 1986-2012, 343 828 livebirths of these women were identified. The associations between women's OHC experience and her risk of preterm delivery were analyzed through logistic regression models, adjusting for women's own preterm birth, intrauterine growth, and childhood socioeconomic situation. RESULTS: Compared with women that never entered OHC, women with OHC experience up to and after age 10 were both associated with increased risks of preterm delivery (adjusted odds ratio [aOR] = 1.23 [95% confidence interval 1.08-1.40] and aOR = 1.29 [1.13-1.48], respectively). Women who experienced OHC before or at 10 years of age had increased risk of both spontaneous and medically indicated preterm delivery (aOR = 1.19 [1.03-1.38] and aOR = 1.27 [1.02-1.59], respectively). Women who experienced OHC after age 10 had a more pronounced risk of medically indicated preterm delivery (aOR = 1.76 [1.44-2.16]) than for spontaneous preterm delivery (aOR = 1.08 [0.92-1.27]). CONCLUSIONS: Women who were placed in OHC in childhood had increased risk of preterm delivery independent from their own perinatal history. Stress response, as 1 consequence of early life adversities, may take its toll on women's reproductive health and their offspring, calling for integrative efforts in preventing early life adversity.