Background. The terrorist explosions of the World Trade Center in New York City and the other events on the Pentagon and in Pennsylvania on 11 September 2001 were stressful events that affected people around the world. Pregnant women and their offspring are especially vulnerable during and after such a terrorist attack. The objective was to systematically review the risks of adverse pregnancy outcomes after the terrorist attacks on Sept 11, 2001. Methods. The Meta-analysis of Observational Studies in Epidemiology (MOOSE) criteria were used for reporting of this review. Statistical analyses were performed using RevMan 5.0. Results. Ten reports of low-to-moderate risk of methodological bias were included. There was increased risks of infants with birthweight of 1,500 g–1,999 g (adjusted odds ratio [AOR] 1.67 [95%CI 1.11–2.52]) and small-for-gestational age births (AOR 1.90; 95%CI 1.05–3.46) in New York. There was increased risks of low birthweight (relative risk 2.25; 95%CI 1.29–3.90) and preterm births (relative risk 1.50; 95%CI 1.06–2.14) among ethnically Arabic women living in California There was a reduction in birthweight by 276 g and in head circumference by 1 cm when DNA adducts, a marker for environmental toxin exposure, were doubled in maternal blood. In Holland, a 48-g reduction in birthweight was reported. Conclusions. The World Trade Center disaster influenced pregnancy outcomes in New York, among ethnically Arab women living in California and among Dutch women. The adverse outcomes are likely due to environmental pollution and stress in New York, ethnic harassment in California and communal bereavement and stress in Holland.