Table 3 Association between exposure to SARS-CoV-2 during pregnancy exposure period and neonatal outcomes, calculated using conditional logistic regression

From: Neonatal and maternal outcomes following SARS-CoV-2 infection and COVID-19 vaccination: a population-based matched cohort study

Cohort (Outcome)

Infection status

Number of pregnancies/ neonates

Number with outcome

% with outcome

Odds ratio accounting for only matchinga [95% CI]

P valuea

Adjusted odds ratiob [95% CI]

P valueb

1 (Stillbirths)

Infected

4074

14

0.3%

1.02 [0.55–1.88]

0.94

1.08 [0.56–2.05]

0.82

 

Uninfected

12,222

41

0.3%

Ref

–

Ref

 -

1 (Extended perinatal death)

Infected

4074

23

0.5%

1.13 [0.70–1.82]

0.62

1.13 [0.68–1.89]

0.63

 

Uninfected

12,222

61

0.5%

Ref

–

Ref

 -

2 (Neonatal death)

Infected

4060

9

0.2%

2.25 [0.95–5.34]

0.07

–

 -

 

Uninfected

12,180

12

0.1%

Ref

–

–

–

3 (Small for gestational age (<10th percentile)c)

Infected

3947

185

4.5%

0.91 [0.77-1.08]

0.26

1.04 [0.86-1.26]

0.67

 

Uninfected

11,532

592

5.0%

Ref

–

Ref

–

3 (Very small for gestational age (<3rd percentile)c)

Infected

3947

38

0.9%

0.88 [0.61-1.26]

0.48

1.02 [0.65-1.61]

0.93

 

Uninfected

11,532

126

1.1%

Ref

–

Ref

–

4 (Low Apgar score (<7)c)

Infected

3663

64

1.7%

0.99 [0.74-1.32]

0.95

0.96 [0.71-1.30]

0.80

 

Uninfected

10,594

184

1.6%

Ref

–

Ref

–

4 (Very low Apgar score (<4)c)

Infected

3663

10

0.3%

0.77 [0.38–1.54]

0.46

0.87 [0.42–1.81]

0.72

 

Uninfected

10,594

37

0.3%

Ref

–

Ref

–

5 (Preterm birth)

Infected

3603

274

7.6%

1.37 [1.18-1.59]

<0.001

1.36 [1.16-1.59]

<0.001

 

Uninfected

10,809

611

5.7%

Ref

–

Ref

–

5 (Spontaneous preterm birthc)

Infected

3597

149

4.1%

1.25 [1.03-1.52]

0.03

1.27 [1.03-1.56]

0.03

 

Uninfected

10,787

361

3.3%

Ref

-

Ref

-

5 (Provider-initiated preterm birthc)

Infected

3597

119

3.3%

1.46 [1.17-1.82]

<0.001

1.42 [1.11-1.81]

0.005

 

Uninfected

10,787

246

2.3%

Ref

–

Ref

–

6 (Very preterm birth)

Infected

2842

38

1.3%

1.68 [1.13–2.49]

0.01

1.90 [1.20–3.02]

0.01

 

Uninfected

8526

68

0.8%

Ref

–

Ref

–

6 (Spontaneous very preterm birthc)

Infected

2841

22

0.8%

1.29 [0.77–2.13]

0.31

1.31 [0.78–2.18]

0.31

 

Uninfected

8522

51

0.6%

Ref

–

Ref

–

6 (Provider-initiated very preterm birthc)

Infected

2841

15

0.5%

2.81 [1.39–5.69]

<0.001

2.63 [1.23–5.62]

0.01

 

Uninfected

8522

16

0.2%

Ref

–

Ref

–

  1. CI confidence interval.
  2. aMatched for maternal age, gestation at infection/matching and seasons of conception.
  3. bAdjustment for deprivation only for analyses with the following outcomes: spontaneous very preterm birth and provider-initiated very preterm birth. Adjustment for parity and deprivation only for analyses with the following outcomes: stillbirth, extended perinatal death, and very low Apgar score. Adjustment for all covariates apart from parity for the following outcomes: preterm birth, spontaneous preterm birth, provider-initiated preterm birth and very preterm birth. Adjustment for all covariates for analyses for the following outcomes: small for gestational age, very small for gestational age, and low Apgar score.
  4. cFor these outcomes there is not an exact match of three uninfected controls to each neonate exposed to infection as neonates with missing outcome data have been removed from analysis; see Methods for further details on missing data.
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