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A Murine Model of Fetal Exposure to Maternal Inflammation to Study the Effects of Acute Chorioamnionitis on Newborn Intestinal Development
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A Murine Model of Fetal Exposure to Maternal Inflammation to Study the Effects of Acute Chorioamnionitis on Newborn Intestinal Development

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Microbial invasion of the amniotic cavity in pregnancies with small-for-gestational-age fetuses

Daniel B DiGiulio1, Maria Teresa Gervasi, Roberto Romero

  • 1Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA.

Journal of Perinatal Medicine
|May 21, 2010
PubMed
Abstract

Insights

Microbial invasion of the amniotic cavity (MIAC) was detected in 6% of small-for-gestational-age (SGA) neonates using PCR, suggesting a role for intrauterine infection in fetal growth restriction. This finding was not apparent with traditional culture methods.

Area of Science:

  • Obstetrics and Gynecology
  • Maternal-Fetal Medicine
  • Microbiology

Background:

  • Microbial invasion of the amniotic cavity (MIAC) is linked to adverse pregnancy outcomes like preterm labor and PROM.
  • Intrauterine infection is a suspected contributor to fetal growth restriction (FGR).
  • The prevalence of MIAC in pregnancies complicated by small-for-gestational-age (SGA) fetuses remains largely uncharacterized.

Purpose of the Study:

  • To investigate the frequency, diversity, and relative abundance of microbes in amniotic fluid (AF) of women delivering SGA neonates.
  • To compare culture-based and molecular detection methods for MIAC in this population.

Main Methods:

  • Retrospective cohort study analyzing AF from 52 pregnancies with SGA neonates.
  • Utilized both cultivation techniques and molecular methods (broad-range and group-specific PCR assays targeting small subunit rDNA).
  • Correlated microbiologic findings with indicators of the maternal inflammatory response.

Main Results:

  • Cultivation methods yielded no microbial growth in any AF samples (0/52).
  • Molecular methods detected MIAC in 6% (3/52) of AF samples.
  • Intra-amniotic inflammation was observed in one of the three PCR-positive cases, compared to 6.1% of PCR-negative cases (P=0.2).

Conclusions:

  • PCR-based detection identified MIAC in a subset of pregnancies with SGA fetuses, even in the absence of labor at the time of AF collection.
  • These findings suggest that MIAC may play a role in the pathophysiology of FGR.
  • Molecular methods offer a more sensitive approach to detecting MIAC compared to traditional cultivation.

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