Table 1 Basic characteristics of the studies included in this meta-analysis
First Author | Study design | Study time | Country | Exposure vaccine | Vaccination exposure time of HPV vaccine group | Comparison | Vaccination (or placebo) exposure time of control group |
|---|---|---|---|---|---|---|---|
Kharbanda (2018) [12] | retrospective observational cohort | 2008.01–2014.11 | the United States | 4vHPV | within (1) peripregnancy: 42 days before LMP; (2) during pregnancy: first 19 weeks of pregnancy; (3) peri or during pregnancy: 42 days before LMP to 19 weeks of gestation | 4vHPV | 4vHPV vaccinated within 16 to 22 weeks before LMP |
Scheller (2017) [2] | retrospective observational cohort | 2006.10.1–2013.11 | Denmark | 4vHPV | within 7 to 22 weeks of pregnancy | 4vHPV | 4vHPV not vaccinated during 7 to 22 weeks of pregnancy |
Moreira (2016) [13] | combined analysis of 7 phase three clinical trials | NA | 31 countries | 9vHPV and 4vHPV | within 30 days before and after conception a | 9vHPV and 4vHPV | 9vHPV or 4vHPV not vaccinated during 30 days before and after conception |
Panagiotou (2015) [14] | long term observational follow-up in the Costa Rica HPV Vaccine Trial | 2004.6–2013.12 | Costa Rica | 2vHPV | within 90 days before and after conception | hepatitis A vaccine or unvaccination | not vaccinated HPV vaccine |
Baril (2015) [15] | retrospective observational cohort | 2008.9–2011.6 | United Kingdom | 2vHPV | within 90 days before and 30 days after LMP | 2vHPV | 2vHPV vaccinated within 4 to 18 months before LMP |
Angelo (2014) [16] | pooled analysis of data from 42 completed/ongoing clinical studies | NA | 40 countries | 2vHPV | within (1) 45 days before and 30 days after pregnancy; (2) 60 days before pregnancy to pregnancy end; (3) first 12 weeks of pregnancy | placebo (Al (OH)3), Havrix, hepatitis A vaccine, Gardasil, Menactra, Boostrix, Boostrix Polio, Engerix B or Twinrix Paediatri | vaccination with control vaccine within 60 days before pregnancy to pregnancy end |
Garland (2009) [18] | combined analysis of five randomized controlled trials | NA | multiple countries | 4vHPV | within 30 days before conception | placebo | vaccination with placebo within 30 days before conception |