There was an increase in the number of babies that were delivered less than full-term, or under 39 weeks, the report said. And preterm babies — those born before 37 weeks of gestation — accounted for 10.02% of births in 2018, up from 9.93% in 2017. Early-term births — those born between 37 and 38 weeks of pregnancy — also increased from 26% in 2017 to 26.53% in 2018.