Table 2 Reproductive risk factors of small for gestational age (SGA) among the total population of singleton live births ( n = 1,390,165) for the years 1987–2010 in Finland

Pregravid BMI^a

≤0.001

≤24.9

72.8

66.9

25–29.9

17.8

21.6

≥30

9.4

11.5

Non-smoking

71.1

84.9

≤0.001

Quitted smoking

4.5

3.5

Smoking

24.3

11.6

Married or cohabiting

93.7

95.9

≤0.001

Mean number of deliveries (±SD)

0.71 (±1.22)

1.04 (±1.35)

≤0.001

Mean number of pregnancies (±SD)

1.18 (±1.63)

1.48 (±1.70)

≤0.001

Mean number of miscarriages (±SD)

0.26 (±0.65)

0.26 (±0.61)

0.72

Mean number of prior terminations (±SD)

0.14 (±0.45)

0.12 (±0.41)

≤0.001

IVF^b

1.3

1.1

0.001

Anemia ≤ 100 g/l

0.6

0.6

0.28

Prior Cesarean section

7.6

8.4

≤0.001

Chorionic villus biopsy

1.1

0.9

≤0.001

Amniocentesis

3.9

2.7

≤0.001

Placenta previa

0.3

0.2

≤0.001

Placental abruption

0.6

0.2

≤0.001

Induction

18.8

13.3

≤0.001

Congenital anomalies

8.7

2.8

≤0.001

Socioeconomic status

Upper white-collar worker

5.5

6.7

≤0.001

Lower white-collar worker

31.2

32.6

Blue-collar worker

15.9

13.6

Other

19.5

19.8

Missing

27.9

27.2