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. 2023 May 17;51(7):886-890.
doi: 10.1515/jpm-2022-0604. Print 2023 Sep 26.

Are bacteria, fungi, and archaea present in the midtrimester amniotic fluid?

Roberto Romero  1   2   3   4   5 , Maria Teresa Gervasi  1   6 , Daniel B DiGiulio  7   8 , Eunjung Jung  1   9 , Manaphat Suksai  1   9 , Jezid Miranda  1   10 , Kevin R Theis  1   9   11 , Francesca Gotsch  1   9 , David A Relman  7   8   12
Affiliations

Are bacteria, fungi, and archaea present in the midtrimester amniotic fluid?

Roberto Romero et al. J Perinat Med. .

Abstract

Objectives: This study was conducted to determine whether bacteria, fungi, or archaea are detected in the amniotic fluid of patients who underwent midtrimester amniocentesis for clinical indications.

Methods: Amniotic fluid samples from 692 pregnancies were tested by using a combination of culture and end-point polymerase chain reaction (PCR) techniques. Intra-amniotic inflammation was defined as an interleukin-6 concentration >2,935 pg/mL.

Results: Microorganisms were detected in 0.3% (2/692) of cases based on cultivation, 1.73% (12/692) based on broad-range end-point PCR, and 2% (14/692) based on the combination of both methods. However, most (13/14) of these cases did not have evidence of intra-amniotic inflammation and delivered at term. Therefore, a positive culture or end-point PCR in most patients appears to have no apparent clinical significance.

Conclusions: Amniotic fluid in the midtrimester of pregnancy generally does not contain bacteria, fungi, or archaea. Interpretation of amniotic fluid culture and molecular microbiologic results is aided by the assessment of the inflammatory state of the amniotic cavity. The presence of microorganisms, as determined by culture or a microbial signal in the absence of intra-amniotic inflammation, appears to be a benign condition.

Keywords: chorioamnionitis; contamination; inflammation; microbial survey; sterile womb hypothesis.

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Conflict of interest statement

Competing interests: Authors state no conflicts of interest.

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