Candidate gene analysis of spontaneous preterm delivery: New insights from re-analysis of a case-control study using case-parent triads and control-mother dyads

Table 1 Clinical and demographical characteristics

	Cases (n = 196)	Controls (n = 211)	p
Maternal age (years)	29 [20-34]	30 [21-34]	0.135
Gestational age (days)	253 [172-258]	280 [273-286]	< 0.001
Primiparity	128 (65.3%)	98 (46.4%)	< 0.001
Smoking wk 1-17 of pregnancy (%)	64 (32.7%)	55 (26.1%)	0.124
Pre-pregnancy BMI	23.03 [14.84-41.26]	23.23 [17.30-38.10]	0.561
Birth weight (g)	2815 [747-4000]	3645 [2610-4970]	< 0.001
Gender infant, male	51.5%	42.7%	0.073
Paternal age (years)	31 [20-46]	31 [23-48]	0.561
Previous PTD	18 (9.2%)	3 (1.4%)	< 0.001
Gestational bleeding, 2^nd trimester	28 (15.8%)	21 (10.9%)	0.161

¹ Medians are reported with the range in brackets.
² Cases are defined as preterm delivery < 37 weeks of gestation, while controls are defined as term delivery from 39+0 to 40+6 weeks of gestation.
³ P-values are calculated by Mann-Whitney U test for continuous variables and chi-square test for categorical variables.
⁴ Information about pre-pregnancy BMI and smoking in week 1-17 of pregnancy is self reported and collected from MoBa Questionnaire 1.

ISSN: 1471-2350