Table 1 Characteristics of the study population^a

Age, mean years (SD)

31.6 (4.9)

32.3 (4.9)

 <25

45 (6.9)

3 (8.3)

Ref.

 25-29

174 (26.9)

7 (19.4)

0.603 (0.150-2.427)

 30-34

252 (38.9)

16 (44.4)

0.952 (0.267-3.402)

 35-39

136 (21.0)

8 (22.2)

0.882 (0.224-3.469)

 >39

41 (6.3)

2 (5.6)

0.732 (0.116-4.601)

Weeks of gestation, mean (SD)

10.4 (1.9)

9.6 (1.9)

Gravida, mean (SD)

1.8 (0.4)

1.8 (0.4)

 1

148 (22.8)

6 (16.7)

Ref.

 ≥2

500 (77.2)

30 (83.3)

1.480 (0.604-3.624)

Parity, mean (SD)

1.7 (0.5)

1.8 (0.4)

 0

229 (35.3)

7 (19.4)

Ref.

 ≥1

419 (64.7)

29 (80.6)

2.264 (0.977-5.250)

 During conception

58 (9.2) ^b

5 (14.3) ^c

1.652 (0.617-4.422)

 Current

39 (6.1) ^d

2 (5.6)

0.908 (0.210-3.919)

 The Netherlands

476 (74.1)

23 (63.9)

Ref.

 Morocco

29 (4.5)

-

-

 Turkey

16 (2.5)

-

-

 Curaçao

26 (4.0)

3 (8.3)

2.388 (0.673-8.471)

 Suriname

14 (2.2)

4 (11.1)

5.913 (1.804-19.386)

 Other

81 (12.6)

6 (16.7)

1.533 (0.606-3.881)