Table 3 Associations of six types of RTIs during preconception care with adverse pregnancy outcomes

Among 57,708 pregnancies that had pregnancy outcomes

 Spontaneous abortion

  n /N (%)

18 /184 (9.78)

45 /348 (12.93)

2 /79 (2.53)

11 /138 (7.97)

40 /477 (8.39)

90 /1297 (6.94)

3105 /55270 (5.62)

  Crude OR (95%CI)

1.82 (1.12–2.97)

2.50 (1.82–3.42)

0.44 (0.11–1.78)

1.46 (0.79–2.70)

1.54 (1.11–2.13)

1.25 (1.01–1.56)

1.00 (Ref.)

  Adjusted OR^a (95%CI)

1.65 (1.01–2.71)

2.07 (1.50–2.85)

0.38 (0.09–1.56)

1.36 (0.73–2.55)

1.33 (0.96–1.85)

1.14 (0.92–1.42)

1.00 (Ref.)

 Induced abortion / labour due to medical reasons

  n /N (%)

11 /184 (5.98)

20 /348 (5.75)

0 /79 (0)

3 /138 (2.17)

21 /477 (4.40)

39 /1297 (3.01)

1758 /55270 (3.18)

  Crude OR (95%CI)

1.94 (1.05–3.57)

1.86 (1.18–2.92)

/

0.68 (0.22–2.13)

1.40 (0.90–2.18)

0.94 (0.68–1.30)

1.00 (Ref.)

  Adjusted OR^a (95%CI)

1.75 (0.95–3.26)

1.60 (1.01–2.54)

/

0.65 (0.21–2.05)

1.18 (0.76–1.84)

0.84 (0.61–1.17)

1.00 (Ref.)

 Stillbirth

  n /N (%)

0 /184 (0)

0 /348 (0)

0 /79 (0)

0 /138 (0)

1 /477 (0.21)

1 /1297 (0.08)

121 /55270 (0.22)

  Crude OR (95%CI)

/

/

/

/

0.96 (0.13–6.87)

0.35 (0.05–2.52)

1.00 (Ref.)

  Adjusted OR^a (95%CI)

/

/

/

/

0.89 (0.12–6.41)

0.35 (0.05–2.52)

1.00 (Ref.)

Among 51,934 pregnancies with singleton livebirths

 Preterm Birth

  n /N (%)

9 /152 (5.92)

34 /276 (12.32)

3 /76 (3.95)

11 /125 (8.80)

34 /407 (8.35)

91 /1156 (7.87)

3874 /49763 (7.78)

  Crude OR (95%CI)

0.75 (0.38–1.46)

1.66 (1.16–2.39)

0.49 (0.15–1.55)

1.14 (0.62–2.12)

1.08 (0.76–1.54)

1.01 (0.82–1.26)

1.00 (Ref.)

  Adjusted OR^b (95%CI)

0.73 (0.37–1.44)

1.60 (1.12–2.30)

0.48 (0.15–1.52)

1.14 (0.61–2.13)

1.08 (0.76–1.54)

1.01 (0.81–1.25)

1.00 (Ref.)

 Very Preterm Birth

  n /N (%)

2 /152 (1.32)

7 /276 (2.54)

0 /76 (0)

3 /125 (2.40)

13 /407 (3.19)

19 /1156 (1.64)

731 /49763 (1.47)

  Crude OR (95%CI)

0.89 (0.22–3.62)

1.75 (0.82–3.71)

/

1.65 (0.52–5.20)

2.22 (1.27–3.87)

1.12 (0.71–1.77)

1.00 (Ref.)

  Adjusted OR^b (95%CI)

0.89 (0.22–3.60)

1.64 (0.77–3.51)

/

1.79 (0.57–5.67)

2.16 (1.23–3.78)

1.15 (0.72–1.82)

1.00 (Ref.)

 Macrosomia

  n /N (%)

5 /152 (3.29)

9 /273 (3.30)

1 /75 (1.33)

11 /125 (8.80)

27 /405 (6.67)

55 /1148 (4.79)

2061 /49292 (4.18)

  Crude OR (95%CI)

0.78 (0.32–1.90)

0.78 (0.40–1.52)

0.31 (0.04–2.23)

2.21 (1.19–4.12)

1.64 (1.11–2.43)

1.15 (0.88–1.52)

1.00 (Ref.)

  Adjusted OR^b (95%CI)

0.69 (0.28–1.69)

0.76 (0.39–1.48)

0.32 (0.04–2.29)

2.00 (1.07–3.74)

1.58 (1.06–2.34)

1.06 (0.81–1.40)

1.00 (Ref.)

 LGA

  n /N (%)

13 /152 (8.55)

32 /273 (11.72)

5 /75 (6.67)

18 /125 (14.40)

55 /405 (13.58)

115 /1146 (10.03)

4967 /49224 (10.09)

  Crude OR (95%CI)

0.83 (0.47–1.47)

1.18 (0.82–1.71)

0.64 (0.26–1.58)

1.50 (0.91–2.48)

1.40 (1.05–1.87)

0.99 (0.82–1.21)

1.00 (Ref.)

  Adjusted OR^b (95%CI)

0.79 (0.45–1.40)

1.13 (0.78–1.64)

0.64 (0.26–1.59)

1.41 (0.85–2.32)

1.36 (1.02–1.81)

0.96 (0.79–1.17)

1.00 (Ref.)

 LBW

  n /N (%)

1 /152 (0.66)

6 /273 (2.20)

1 /75 (1.33)

2 /125 (1.60)

5 /405 (1.23)

17 /1148 (1.48)

548 /49292 (1.11)

  Crude OR (95%CI)

0.59 (0.08–4.22)

2.00 (0.89–4.51)

1.20 (0.17–8.66)

1.45 (0.36–5.87)

1.11 (0.46–2.70)

1.34 (0.82–2.18)

1.00 (Ref.)

  Adjusted OR^b (95%CI)

0.60 (0.08–4.28)

1.85 (0.82–4.20)

1.14 (0.16–8.28)

1.39 (0.34–5.64)

1.13 (0.46–2.73)

1.31 (0.80–2.14)

1.00 (Ref.)

 SGA

  n /N (%)

8 /152 (5.26)

15 /273 (5.49)

0 /75 (0)

9 /125 (7.20)

30 /405 (7.41)

78 /1146 (6.81)

2848 /49224 (5.79)

  Crude OR (95%CI)

0.91 (0.44–1.85)

0.95 (0.56–1.60)

/

1.26 (0.64–2.49)

1.30 (0.90–1.89)

1.19 (0.94–1.50)

1.00 (Ref.)

  Adjusted OR^b (95%CI)

0.93 (0.45–1.89)

0.98 (0.58–1.65)

/

1.27 (0.64–2.51)

1.32 (0.91–1.93)

1.19 (0.94–1.50)

1.00 (Ref.)