Cluster analysis identifying clinical phenotypes of preterm birth and related maternal and neonatal outcomes from the Brazilian Multicentre Study on Preterm Birth

Objective To explore a conceptual framework of clinical conditions associated with preterm birth (PTB) by cluster analysis, assessing determinants for different PTB subtypes and related maternal and neonatal outcomes. Methods Secondary analysis of the Brazilian Multicentre Study on Preterm Birth of 33 740 births in 20 maternity hospitals between April 2011 and July 2012. In accordance with a prototype concept based on maternal, fetal, and placental conditions, an adapted k-means model and fuzzy algorithm were used to identify clusters using predefined conditions. The mains outcomes were phenotype clusters and maternal and neonatal outcomes. Results Among 4150 PTBs, three clusters of PTB phenotypes were identified: women who had PTB without any predefined conditions; women with mixed conditions; and women who had pre-eclampsia, eclampsia, HELLP syndrome and fetal growth restriction. The prevalence of different preterm subtypes differed significantly in the three clusters, varying from 80.95% of provider-initiated PTBs in cluster 3-6.62% in cluster 1 (P<0.001). Although some maternal characteristics differed among the clusters, maternal and neonatal outcomes did not. Conclusions The analysis identified three clusters with distinct phenotypes. Women from the different clusters had different subtypes of PTB and maternal and pregnancy characteristics.