2.1. Search strategy
The
protocol for the meta-analysis was based on the MOOSE
checklist(6) (Meta-analysis Of Observational Studies
in Epidemiology) and
EQUATOR
Reporting Guidelines(7) (Preferred Reporting Items for
Systematic Reviews and Meta-Analyses). We only conducted a literature
review, thus ethics approval was not required.
We systematically searched the literature in PubMed, Web of Science,
EMBASE, MEDLINE databases. The retrieval period is from January 1, 2020
to April 16,
2020.
The search keywords
are
((COVID-19)
OR (2019 novel coronavirus infection) OR (COVID19) OR (coronavirus
disease 2019) OR (coronavirus disease-19) OR (2019-nCoV disease) OR
(2019 novel coronavirus disease) OR (2019-nCoV infection) OR
(SARS-CoV-2) OR (Wuhan coronavirus) OR (Wuhan seafood market pneumonia
virus) OR (COVID19 virus) OR (COVID-19 virus) OR (coronavirus disease
2019 virus) OR (SARS-CoV-2) OR (SARS2) OR (2019-nCoV) OR (2019 novel
coronavirus)) AND ((Pregnancy) OR (Pregnancies) OR (Gestation) OR
(Pregnant Women) OR (Pregnant Woman) OR (Woman, Pregnant) OR (Women,
Pregnant)). The literature has no language restrictions. We used Endnote
X7 library (Clarivate Analytics, Philadelphia, PA, USA) to remove
duplicate citations and manage the references. We hand-searched
bibliographies of retrieved papers for additional references.