We compared the neonatal and infant outcomes at one year (Bayley mental and psychomotor development index, and physical growth) of babies who were (n = 63) or were not (n = 100) delivered prior to 37 weeks in women admitted in threatened late preterm labor (34-35(+6) weeks) with a cervix ≤15 mm. The women were part of a clinical trial to investigate the tocolytic effect of the oxytocin antagonist barusiban. Babies born late preterm (34-36(+6) weeks) had a significantly increased risk of short-term morbidity (hepatobiliary disorders, respiratory disorders, metabolic disorders, nervous system disorders, infection; p < 0.05 for each) compared with those born at term, but there were no significant differences in the neurodevelopmental and physical outcomes at one year (p > 0.05 for both one-year outcomes).