Table 5.

Factors independently associated with APO* in preterm newborns: multiple analyses by Poisson regression [n = 837].

Variables	RRadj	95%CI	p-value
Pi-PTB	8.12	2.54–25.93	0.007
Weight gain rate per week 20–27 weeks <p10	2.04	1.23–3.38	0.018
Region (Northeast)	2.35	1.11–4.95	0.034

Variables included in the model: Region; ethnicity; annual family income; source of prenatal care; smoking status; previous maternal condition; cervical length from 18 to 24 weeks <25 mm; weight gain rate per week 20–27 weeks <Q1; weight gain rate per week 20–27 weeks <Q2; weight gain rate per week 20–27 weeks <p10; weight gain rate per week 20–27 weeks >p90; sPTB; pi-PTB; gestational age at birth; Preeclampsia; Hyperglycaemia in pregnancy. *APO: NICU stay >7 days or intubation at birth or Apgar score <7 at 5 minutes or fetal/neonatal death or discharge home on oxygen or neonatal sepsis or cyanosis or hypoglycaemia or birth asphyxia or respiratory distress or mechanical ventilation.