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Modeling Ascending Vaginal Infection, Preterm Birth, and Neonatal Morbidity in Mice
Published on: October 10, 2025
Complement activation fragment Bb in early pregnancy and spontaneous preterm birth
Anne M Lynch1, Ronald S Gibbs, James R Murphy
1Department of Obstetrics and Gynecology, University of Colorado Denver, Denver, CO 80045, USA. anne.lynch@uchsc.edu
American Journal of Obstetrics and Gynecology
|October 22, 2008
Summary
Elevated levels of complement fragment Bb in early pregnancy significantly increase the risk of spontaneous preterm birth (SPTB) before 34 weeks gestation. This finding suggests early pregnancy inflammation plays a role in SPTB pathogenesis.
Area of Science:
- Reproductive Immunology
- Maternal-Fetal Medicine
- Complement System Biology
Background:
- Spontaneous preterm birth (SPTB) before 34 weeks gestation is a major obstetric concern.
- The role of early pregnancy inflammatory markers in SPTB is not fully understood.
Purpose of the Study:
- To investigate the association between elevated complement activation fragment Bb levels in early pregnancy and SPTB.
- To differentiate the association with early SPTB (<34 weeks) versus late SPTB (34-37 weeks).
Main Methods:
- Prospective study of 784 women enrolled before 20 weeks gestation.
- Measurement of complement activation fragment Bb levels.
- Statistical analysis to determine the risk of SPTB based on Bb quartiles.
Main Results:
- Women in the top quartile of Bb levels had a 4.7-fold increased likelihood of SPTB before 34 weeks gestation (P = .003).
- No significant association was found between Bb levels and late SPTB (34-37 weeks gestation).
Conclusions:
- Elevated Bb in early pregnancy is a significant predictor of early SPTB (<34 weeks).
- These findings support the hypothesis that inflammatory processes in early pregnancy contribute to the pathogenesis of SPTB.
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