N

Singleton N = 125

Twins N = 34

Age

years

159

25 30 33

30 33 35

BMI

kg/m2

159

23 26 29

24 27 29

History of preterm birth

159

11.2% (14)

5.9% (2)

Prity

159

0

52.0% (65)

64.7% (22)

1

28.8% (36)

17.6% (6)

>1

19.2% (24)

17.6% (6)

Gravidity

159

1

48.0% (60)

61.8% (21)

2

20.0% (25)

14.7% (5)

>2

32.0% (40)

23.5% (8)

Gestation age at hospitalization

day

159

28 + 1 29 + 5 31 + 6

27 + 0 29 + 1 30 + 4

Cervical length

mm

159

14.0 20.0 30.0

13.0 18.0 22.8

Lung maturation

159

65.6% (82)

91.2% (31)

Gestation age at birth

day

159

36 + 3 38 + 1 39 + 3

33 + 1 35 + 1 36 + 2

Fetal weight at birth

g

157

2770 3050 3400

1962 2202 2551

Days of hospitalization

day

132

2.00 4.00 8.00

4.75 7.50 13.25

Preterm birth before 37 + 0 weeks

159

31.2% (39)

85.3% (29)

Preterm birth before 34 + 0 weeks

159

8.8% (11)

32.4% (11)

Tocolysis

159

84.8% (106)

91.2% (31)

Vaginal bacterial or yeast colonization

159

37.6% (47)

26.5% (9)