Introduction A recent increase in cases of advanced maternal age in the US has been partly associated with a higher incidence of pregnancy-related complications and infertility. However, little is known on how such social changes may have influenced obstetrics articles published in high-impact medical journals subscribed by diverse physicians. The objective of this study is to elucidate the presence and trend of obstetrics investigations in high-profile medical journals. Material and methods This bibliometric study retrospectively analyzed original articles published in the Journal of the American Medical Association (JAMA) from 1997 to 2016. Two reviewers extracted obstetrics articles from PubMed, assessed whether to include specific articles, and categorized them by subtopic. Main outcomes measure was the annual number of original investigations in obstetrics divided by that of original investigations from all fields during the study period, expressed as a trend. Results A total of 3486 original investigations were published during the study period. Regarding obstetrics, 1989 articles were originally extracted from PubMed; after a two-step review process, 199 (10.0%) obstetrics-related original investigations remained. Among them, 134 (67.4%) were classified as pregnancy-related abnormalities or complications (non-infection). The proportion of obstetrics articles decreased during the first 10 years but increased in the last 10 years. The highest figures in the first 10 and last 10 years were 8.5% in 1999 and 9.4% in 2014, respectively, whereas the lowest was 1.4% in 2008. The proportion articles on pregnancy-associated complications or abnormalities (non-infection) steadily increased during the study period, that of articles on infertility increased, and that of articles on human immunodeficiency virus (HIV) infection steadily decreased. Conclusions The observed trend may suggest a changing interest in obstetrics investigations among general physicians in the last 20 years. What is particularly notable is a heightened presence of research on pregnancy-related complications and infertility, which may reflect an increasing frequency in advanced maternal age in the US.
Keywords: advanced age; bibliometric; complication; human immunodeficiency virus; infertility; marriage.