Table 1

Baseline characteristics of the cases and their matched controls

Characteristic

Cases

n = 103

Controls

n = 103

Mean Difference (95% CI*) or P-value

Age (mean) years

57.7

57.2

0.5 (-3.6; 2.7)

Mean age at first pregnancy

25.6

26.1

-0.5 (-1.0; 1.9)

Mean age at diagnosis (SSc**)

53.0^#

NA

NA

Body Mass Index during first pregnancy

22.2

22.7

-0.5 (-1.4; 0.3)

Sex of children

Male

30% (31)

19.4% (20)

0.1

Female

16.5% (17)

22.3% (23)

0.4

Both

47.5% (49)

57.3% (59)

0.2

Number of pregnancies

Mean

2.46

2.41

0.1 (-0.3; 0.2)

Primipara

13.6% (14)

13.6% (14)

1.0

Multipara

86.4% (89)

86.4% (89)

1.0

Smoking during pregnancy (% yes)

18% (18.5)

22% (23)

0.5

*CI, confidence interval; **SSc, systemic sclerosis; ^#n = 61 (59.2%), data not complete for all cases

van Wyk et al. Arthritis Research & Therapy 2011 13:R183   doi:10.1186/ar3510