J Korean Med Sci.  2018 Aug;33(35):e220. 10.3346/jkms.2018.33.e220.

Complement C3a, But Not C5a, Levels in Amniotic Fluid Are Associated with Intra-amniotic Infection and/or Inflammation and Preterm Delivery in Women with Cervical Insufficiency or an Asymptomatic Short Cervix (≤ 25 mm)

• Kim YM
• Park KH
• Park H
• Yoo HN
• Kook SY
• Jeon SJ

• KMID: 2418954
• DOI: http://doi.org/10.3346/jkms.2018.33.e220

Abstract

BACKGROUND
We aimed to estimate whether elevated levels of complement C3a and C5a in amniotic fluid (AF) are independently associated with increased risks of intra-amniotic infection and/or inflammation (IAI) and spontaneous preterm delivery (SPTD) in women with cervical insufficiency or a short cervix (≤ 25 mm).
METHODS
We conducted a retrospective cohort study of 96 consecutive women with cervical insufficiency (n = 62) or a short cervix (n = 34) at 17 to 27 weeks, and who underwent an amniocentesis. AF was cultured and analyzed for C3a and C5a by enzyme-linked immunosorbent assay kits. The primary outcome measures were IAI (defined as a positive AF culture and/or an elevated AF interleukin-6 level [≥ 7.6 ng/mL]) and SPTD at < 32 weeks.
RESULTS
In multivariable analysis, AF level of C3a was the only variable significantly associated with IAI, whereas C5a level in AF and serum C-reactive protein level were not associated with IAI. Using SPTD at < 32 weeks as the outcome variable in logistic regression, elevated AF levels of C3a were associated with increased risk of SPTD at < 32 weeks after adjusting for other baseline confounders, whereas elevated AF levels of C5a were not.
CONCLUSION
In women with cervical insufficiency or a short cervix, elevated AF level of C3a, but not C5a, is independently associated with increased risks of IAI and SPTD at < 32 weeks. These findings suggest that subclinical IAI or SPTD in the context of cervical insufficiency is related to activation of complement system in AF.

Keyword

Amniotic Fluid; Complement C3a, C5a; Cervical Insufficiency; Intra-amniotic Infection; Preterm Delivery

MeSH Terms

Amniocentesis
Amniotic Fluid*
C-Reactive Protein
Cervix Uteri*
Cohort Studies
Complement C3a*
Complement System Proteins*
Enzyme-Linked Immunosorbent Assay
Female
Humans
Inflammation*
Interleukin-6
Logistic Models
Outcome Assessment (Health Care)
Retrospective Studies
C-Reactive Protein
Complement C3a
Complement System Proteins
Interleukin-6