Villitis of unknown etiology (VUE) is a chronic inflammatory lesion of the placenta, and the authors performed a systematic review and meta-analysis evaluating the relationship of VUE to five adverse pregnancy outcomes. The incidence of VUE was higher in the fetal growth restricted (IUGR), preeclampsia (PE), gestational hypertension, small for gestational age (SGA) and stillbirth groups compared to controls. VUE was significantly associated with an increased risk of stillbirth with OR = 3.64 (95% CI 1.80–7.39). VUE was also significantly associated with preeclampsia with OR = 1.31 (95% CI 1.03–1.65). A marginal association was observed between VUE and gestational hypertension (OR = 1.41, 95% CI 0.892–2.23). The associations of VUE with IUGR (OR = 1.56, 95% CI 0.509–4.77) and with SGA (OR = 1.01, 95% CI 0.099–10.4) were not statistically significant, and these analyzes showed high heterogeneity. The authors conclude that VUE is mainly associated with the pathogenesis of stillbirth and preeclampsia, while the evidence for IUGR and SGA is uncertain.