Table 2. Risk ratios for any infection in the first year of life comparing infants born to mothers with systemic lupus erythematosus (SLE) to infants born to mothers from the general population, overall and by preterm birth.

	Infants born to mothers with SLE, no. cases/total (%)	Infants born to general population comparators, no. cases/total (%)	Unadjusted risk ratio(95% CI)	Adjusted risk ratio(95% CI)*
Any infection in the first 3 days
Overall	26/1248 (2.1)	414/34 886 (1.2)	1.75 (1.19 to 2.60)	1.63 (1.09 to 2.42)
Term birth	11/1083 (1.0)	313/33 291 (0.9)	1.08 (0.60 to 1.97)	0.98 (0.53 to 1.80)
Preterm birth (32–37 weeks)	4/136 (2.9)	38/1354 (2.8)	1.05 (0.38 to 2.89)	1.01 (0.36 to 2.79)
Very preterm birth (<32 weeks)	11/32 (34.4)	63/241 (26.1)	1.32 (0.78 to 2.22)	1.32 (0.77 to 2.25)
Any infection in the first month of life
Overall	65/1248 (5.2)	1586/34 886 (4.5)	1.15 (0.90 to 1.46)	1.12 (0.88 to 1.43)
Term birth	44/1080 (4.1)	1436/33 291 (4.3)	0.94 (0.70 to 1.27)	0.92 (0.68 to 1.23)
Preterm birth (32–37 weeks)	10/136 (7.4)	80/1354 (5.9)	1.24 (0.66 to 2.34)	1.18 (0.62 to 2.26)
Very preterm birth (<32 weeks)	11/32 (34.4)	70/241 (29.1)	1.18 (0.71 to 1.99)	1.19 (0.71 to 2.02)
Any infection in the first year of life
Overall	478/1248 (38.3)	12 985/34 886 (37.2)	1.03 (0.96 to 1.11)	1.09 (1.01 to 1.17)
Term birth	400/1080 (37.0)	12 270/33 291 (36.9)	1.00 (0.93 to 1.09)	1.07 (0.99 to 1.16)
Preterm birth (32–37 weeks)	59/136 (42.4)	569/1354 (42.0)	1.03 (0.84 to 1.26)	1.06 (0.86 to 1.29)
Very preterm birth (<32 weeks)	19/32 (59.4)	146/241 (60.6)	0.98 (0.72 to 1.33)	0.99 (0.73 to 1.35)

Any infection is defined as a visit listing an ICDInternational Classification of Diseases code for infection as a primary or secondary diagnosis in the inpatient or outpatient components of the National Patient Register or a dispensed anti-infective listed in the Prescribed Drug Register.

^*Models are adjusted for maternal age at delivery (continuous), maternal first-trimester smoking (yes/no/missing), and calendar year (continuous).