Table 1 Univariate and multivariate predictors of survival of very preterm infants in our study (N = 101)

Gestational age (per 1 week increase)

2.0 (1.4–2.9)

2.5 (1.1–5.5)

1.9 (1.1–3.4)

0.03

Birth weight in grams (per 100 g increase)

1.4 (1.2–1.6)

1.2 (0.88–1.6)

1.2 (0.93–1.5)

0.19

C-section vs. vaginal delivery

4.2 (1.8–9.8)

2.4 (0.48–12.2)

2.1 (0.67–6.8)

0.20

Steroid use (mg)

 0

Reference

Reference

Reference

 12

3.2 (0.75–13.2)

7.2 (0.59–86.9)

3.4 (0.49–23.9)

0.22

 24

2.0 (0.75–5.5)

1.3 (0.25–7.2)

1.3 (0.31–5.6)

0.71

 > 24

3.9 (0.95–15.7)

0.60 (0.04–7.9)

2.9 (0.43–19.0)

0.28

Maternal age in years (per unit increase)

1.1 (0.99–1.2)

1.1 (0.97–1.3)

1.1 (0.96–1.2)

0.19

Year of birth (per year increase)

1.2 (0.92–1.6)

0.95 (0.56–1.6)

1.1 (0.71–1.6)

0.73

Maternal parity

 Primiparous

Reference

Reference

Reference

 2–4

0.88 (0.38–2.0)

1.3 (0.23–7.2)

0.59 (0.15–2.4)

0.45

 5–9

0.82 (0.19–3.5)

0.80 (0.03–18.5)

0.43 (0.05–3.6)

0.44

History of preterm delivery

 0

Reference

Reference

Reference

 ≥ 1

0.77 (0.30–1.96)

0.88 (0.13–6.0)

1.3 (0.30–5.4)

0.73

Hb at delivery (per unit increase) [missing n = 23]

1.1 (0.77–1.5)

1.1 (0.60–1.9)

–

–

Time of birth

 0000 to < 0800

Reference

Reference

Reference

 0800 to < 1700

1.9 (0.69–5.1)

7.4 (1.0–54.7)

2.5 (0.56–11.3)

0.23

 1700 to 2400

1.5 (0.51–4.7)

3.4 (0.43–27.5)

3.0 (0.62–14.4)

0.17

Any of maternal complications (hypertension or diabetes)

0.86 (0.37–2.0)

0.22 (0.04–1.4)

0.30 (0.08–1.1)

0.07