Increasing rates of prematurity and epidemiology of late preterm birth.

Preterm birth rates in Australia have risen in the last two decades, mostly accounted for by the rise in late preterm births. Late preterm births (34-36 weeks) comprise 70% of all preterm births, which translates to approximately 16,000 births annually in Australia. The precise causes for this trend are unclear; however, possible aetiologies include increasing maternal age, increased use of artificial reproductive technologies and increased multiple births. Compared with term-born children, late preterm children not only have increased mortality and in-hospital morbidity including respiratory difficulties, but also long-term cognitive, school performance, behaviour and psychiatric problems. The potential public health and educational burden of late preterm birth is considerable. More research is required in this area to understand the risk factors for late preterm birth and to help identify those children at highest risk of developmental deficits.