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Table 2 Association between exposure to HPV Vaccination and spontaneous abortion

From: Peri-conceptional or pregnancy exposure of HPV vaccination and the risk of spontaneous abortion: a systematic review and meta-analysis

Vaccine

Exposure windows

Number of studies

Vaccine exposure group (total, n)

Vaccine exposure group (SA, n)

Control group (total, n)

Control group (SA, n)

RR

95% CI

I 2

RD (%)

95% CI (%)

I 2

2vHPV

Pre-90 days to pregnancy end

3

1176

155

4308

521

1.15

0.95–1.39

0.0

1.6

−0.8-4.1

0.0

Pre-45 days to pregnancy end

2

680

85

1046

99

1.28

0.96–1.70

0.0

2.7

−0.7-6.1

0.0

Pre-45 days to LMP

1

317

48

316

30

1.59

1.04–2.45

5.6

0.2–11.1

During pregnancy (0–12 GWs)

1

137

16

124

17

0.85

0.45–1.61

−2.0

−10.7-6.6

4vHPV

Pre-45 days to pregnancy end

4

2557

238

4257

389

0.88

0.73–1.06

0.0

−1.3

−2.9-0.3

0.0

Pre-45 days to LMP

3

1199

141

2405

276

1.00

0.80–1.24

0.0

0.1

−2.5-2.7

0.0

During pregnancy

2

1358

97

2771

209

0.79

0.62–1.01

0.0

−1.8

−3.5-0.1

0.0

9vHPV

Pre-30 days to first 30 days of pregnancy

1

97

17

1418

122

2.04

1.28–3.24

8.9

1.2–16.6

  1. 2vHPV bivalent HPV vaccine, 4vHPV quadrivalent HPV vaccine, 9vHPV nonavalent HPV vaccine, LMP Last menstrual period, SA Spontaneous abortion, RR Relative risk, RD Risk difference