Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Oct 21;9(1):475.
doi: 10.1186/s13104-016-2280-3.

Clinical trials registries are underused in the pregnancy and childbirth literature: a systematic review of the top 20 journals

Vadim V Yerokhin  1 , Branden K Carr  2 , Guy Sneed  3 , Matt Vassar  2
Affiliations

Clinical trials registries are underused in the pregnancy and childbirth literature: a systematic review of the top 20 journals

Vadim V Yerokhin et al. BMC Res Notes. .

Abstract

Background: Systematic reviews and meta-analyses that do not include unpublished data in their analyses may be prone to publication bias, which in some cases has been shown to have deleterious consequences on determining the efficacy of interventions.

Methods: We retrieved systematic reviews and meta-analyses published in the past 8 years (January 1, 2007-December 31, 2015) from the top 20 journals in the Pregnancy and Childbirth literature, as rated by Google Scholar's h5-index. A meta-epidemiologic analysis was performed to determine the frequency with which authors searched clinical trials registries for unpublished data.

Results: A PubMed search retrieved 372 citations, 297 of which were deemed to be either a systematic review or a meta-analysis and were included for analysis. Twelve (4 %) of these searched at least one WHO-approved clinical trials registry or clinicaltrials.gov.

Conclusion: Systematic reviews and meta-analyses published in pregnancy and childbirth journals do not routinely report searches of clinical trials registries. Including these registries in systematic reviews may be a promising avenue to limit publication bias if registry searches locate unpublished trial data that could be used in the systematic review.

Keywords: Clinical trials registries; Obstetrics; Pregnancy and childbirth; Publication bias; Systematic review.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
PRISMA flow diagram of selection process for analysis
Fig. 2
Fig. 2
Frequency of clinical trials registry search by systematic reviews and meta-analyses published in the top 20 pregnancy and childbirth journals
Fig. 3
Fig. 3
Temporal trend of clinical trials registry search by systematic reviews in the top 20 pregnancy and childbirth journals. The number (left vertical axis) of systematic reviews and meta-analyses searching (blue line) and not searching (orange line) clinical trials registries between 2007 and 2015. The grey bars represent the percentage (right vertical axis) of systematic reviews and meta-analyses that searched clinical trials registries for the given year
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Higgins J, Green S, Cochrane Collaboration . Cochrane handbook for systematic reviews of interventions Chichester. Hoboken: Wiley-Blackwell; 2011.
    1. Abajobir AA, Maravilla JC, Alati R, Najman JM. A systematic review and meta-analysis of the association between unintended pregnancy and perinatal depression. J Affect Disord. 2016;192:56–63. doi: 10.1016/j.jad.2015.12.008. - DOI - PubMed
    1. Hart B, Lundh A, Bero L. Effect of reporting bias on meta-analyses of drug trials: reanalysis of meta-analyses. BMJ. 2012;344:d7202. doi: 10.1136/bmj.d7202. - DOI - PubMed
    1. Blackwell SC, Thompson L, Refuerzo J. Full publication of clinical trials presented at a national maternal-fetal medicine meeting: is there a publication bias? Am J Perinatol. 2009;26(9):679–682. doi: 10.1055/s-0029-1220786. - DOI - PubMed
    1. National Institutes of Health: Trends, charts, and maps. (2015). https://www.clinicaltrials.gov/ct2/resources/trends. Accessed 31 Dec 2015.

Publication types