Clinical and subclinical bacterial vaginosis before conception are
associated with spontaneous abortion: a population-based retrospective
cohort study
Abstract
Objective To explore the association of clinical and
subclinical bacterial vaginosis before conception with the risk of
spontaneous abortion. Design Retrospective cohort study.
Setting Mainland China. Population This study included
women who enrolled in and completed the National Free Pre-Pregnancy
Checkups Project between January 1, 2014 and December 31, 2018.
Methods Clinical bacterial vaginosis before conception was
diagnosed according to the Amsel criteria, and subclinical bacterial
vaginosis before conception was defined as any indicators in the Amsel
Criteria being positive but not meeting the diagnostic criteria.
Analyses were performed by multivaribale-adjusted logistic models with
crude and multivaribale-adjusted odds ratios including 95% confidence
interval. Main outcome measures Spontaneous abortion was
defined as fetal death occurring spontaneously before the 28th week of
gestation. Results Of the included participants, 0.27% and
6.97% of them had clinical and subclinical bacterial vaginosis before
conception respectively. A significantly increased risk of spontaneous
abortion was observed for women with preconception bacterial vaginosis
(OR: 1.19, 95% CI: 1.06-1.34). After excluding participants with
preconception bacterial vaginosis, subclinical bacterial vaginosis was
associated with a 15% (13%-18%) increased risk of spontaneous
abortion. And the corresponding multivariable-adjusted ORs of exposure
to abnormal vaginal discharge characteristics, vaginal pH value ≥4.5,
positive clue cell test, and positive Whiff test for spontaneous
abortion were 1.20 (1.03-1.39), 1.15 (1.12-1.18), 1.08 (0.97-1.19), and
1.24 (1.11-1.38). Conclusion Both clinical and subclinical
bacterial vaginosis before conception were prospectively associated with
an increased risk of spontaneous abortion.