. 2019 May 31;14(5):e0217739. doi: 10.1371/journal.pone.0217739

Table 2. Univariate analysis of the associations of the anthropometric measurement values at birth, and the associations of the maternal and neonatal characteristics with BPD or death before 36 weeks postmenstrual age in each gestational age group.

Variables	23⁺⁰–25⁺⁶ weeks (n = 875)	26⁺⁰–28⁺⁶ weeks (n = 1,889)	29⁺⁰–31⁺⁶ weeks (n = 1,898)
Variables	OR (95% CI)	OR (95% CI)	OR (95% CI)
Gestational age^a	2.54 (1.97–3.29)	1.60 (1.44–1.79)	1.30 (1.14–1.50)
Birth weight^b	1.51 (1.34–1.71)	1.29 (1.23–1.35)	1.22 (1.16–1.29)
Birth weight z-score^c	1.44 (1.20–1.73)	1.49 (1.33–1.66)	1.45 (1.16–1.29)
Length at birth^d	1.33 (1.23–1.44)	1.20 (1.16–1.24)	1.15 (1.10–1.19)
Length at birth z-score^c	1.54 (1.30–1.81)	1.42 (1.30–1.55)	1.32 (1.20–1.45)
HC at birth^d	1.33 (1.20–1.48)	1.28 (1.21–1.35)	1.25 (1.17–1.34)
HC at birth z-score^c	1.22 (1.05–1.40)	1.20 (1.11–1.29)	1.26 (1.15–1.38)
FGR in weight (birth weight z-score <-1)	3.97 (1.81–8.73)	2.62 (1.92–3.56)	2.01 (1.56–2.57)
FGR in length (length at birth z-score <-1)	5.01 (2.29–10.95)	2.56 (1.93–3.38)	1.91 (1.49–2.43)
FGR in HC (HC at birth z-score<-1)	2.38 (1.27–4.44)	1.88 (1.44–2.45)	1.85 (1.43–2.39)
Male	1.36 (0.99–1.87)	1.33 (1.11–1.60)	1.41 (1.12–1.76)
PIH	1.26 (0.67–2.35)	1.47 (1.14–1.90)	1.10 (0.86–1.42)
Oligohydramnios^*	1.34 (0.83–2.16)	1.39 (1.05–1.84)	1.52 (1.09–2.10)
Prenatal corticosteroids^**	1.08 (0.79–1.50)	1.11 (0.93–1.34)	0.89 (0.71–1.11)
RDS	1.44 (0.50–4.13)	1.93 (1.23–3.04)	2.74 (2.00–3.76)

^aPer 1 week decrease

^bPer 100 g decrease

^cPer 1 point decrease

^dPer 1 cm decrease.

* Values are missing in 90 infants in the 23⁺⁰–25⁺⁶ weeks group, 168 infants in the 26⁺⁰–28⁺⁶ weeks group, and 138 infants in the 29⁺⁰–31⁺⁶ weeks group.

** Values are missing in 10 infants in the 23⁺⁰–25⁺⁶ weeks group, 29 infants in the 26⁺⁰–28⁺⁶ weeks group, and 138 infants in the 29⁺⁰–31⁺⁶ weeks group.

OR, odds ratio; CI, confidence interval; BPD, bronchopulmonary dysplasia; HC, head circumference; FGR, fetal growth restriction; PIH, pregnancy-induced hypertension; RDS, respiratory distress syndrome.