Table 3 Results of the logistic regression model comparing low birth weight vs normal birth weight newborns

Outcome (low birth weight = 1, normal birth weight = 0)

Log-likelihood = -151.495, chi-square= 295.7, P value < 0.0001

Gestational age (dichotomous: 0 = ≤ 36 weeks, 1 > 36 weeks)

0.01

0.01

0.004–0.03

< 0.0001

Number of fetuses (dichotomous: 0 = single, 1 = multiple)

12.3

6.67

4.27–35.6

< 0.0001

Maternal age

< 25

1.0*

25–29

0.5

0.23

0.2–1.2

0.129

30–34

0.23

0.12

0.09–0.64

0.005

≥ 35

0.28

0.15

0.1–0.78

0.015

Number of prenatal care visits (dichotomous: 0 = 0–4 not satisfactory, 1 => 4 satisfactory)

0.34

0.13

0.16–0.73

0.006

Type of delivery (dichotomous: 0 = eutocic, 1 = caesarean)

2.34

0.74

1.26–4.34

0.007

Number of cigarettes/day during pregnancy (continuous)

1.12

0.06

1.01–1.24

0.032

Course of pregnancy (dichotomous: 0 = physiologic, 1 = pathologic)

2.22

1.13

0.81–6.04

0.12

Marital status of mother (dichotomous: 0 = other, 1 = married)

2.04

1.18

0.66–6.34

0.216

Occupation of mother

Work outside home

1.0*

Unemployed

1.75

0.88

0.65–4.67

0.266

Housewife

1.26

0.48

0.6–2.64

0.534

Number of echographies (continuous)

0.9

0.08

0.75–1.08

0.277

Amniocentesis (dichotomous: 0 = no, 1 = yes)

0.7

0.36

0.25–1.93

0.489

Size of municipality of residence, inhabitants (dichotomous: 0 = ≤ 90.000 i.e. small town, 1 => 90.000, i.e. large town)

1.19

0.38

0.64–2.24

0.583

Birth's order (dichotomous: 0 = 1–4, 1 => 4)

0.55

1.18

0.01–37.28

0.78

Education level of mother (dichotomous: 0 = mother not a high school graduate, 1 = a high school graduate or more)

0.95

0.31

0.5–1.81

0.882

Social support during pregnancy (dichotomous: 0 = no, 1 = yes)

1.04

0.34

0.55–1.96

0.905

Newborn sex (dichotomous: 0 = female, 1 = male)

1.03

0.32

0.56–1.9

0.932