Using latent variable modelling to identify etiological heterogeneity in preterm delivery.

A small but highly morbid class of neonatal deliveries emerged, exhibiting strong continuity across consecutive births (odds ratios >10), independent of a range of maternal and pregnancy-related factors. This group of women, if subject to further investigation, could provide valuable insight into the aetiology of prematurity and associated morbidity, perhaps providing information to improve birth outcomes among all women.