Objective To explore the outcome of monochorionic twin pregnancies affected by selective intrauterine growth restriction (sIUGR) according to the umbilical artery Doppler pattern of the smaller twin.Methods An electronic search of MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov databases (2000-2016) (OR, 18.3 (95% CI,). Twin pregnancies affected by Type I sIUGR were delivered at a significantly later gestational age compared with Type II (MD, 2.8 (95% CI, weeks) and Type III (MD, 2.1 (95% CI, weeks). The degree of birth-weight discordance was higher in Type II compared with Type I (MD, 21.6% (95% CI,) and Type III (MD, 9.3% (95% CI,