Midtrimester amniotic fluid from healthy pregnancies has no microorganisms using multiple methods of microbiologic...

Area of Science:

• Microbiology
• Obstetrics
• Genetics

Background:

• Controversy exists regarding bacterial presence in amniotic fluid.
• Recent sequencing studies suggest microbial colonization, but contamination is a concern.
• This study addresses the presence of microorganisms in amniotic fluid during healthy pregnancies.

Purpose of the Study:

• To determine if midtrimester amniotic fluid from patients with normal pregnancy outcomes harbors a microbial signature.
• Investigate the microbial content of amniotic fluid in a prospective cohort.

Main Methods:

• Prospective cohort study of 42 amniotic fluid samples from 37 pregnancies.
• Utilized cultivation, quantitative real-time polymerase chain reaction (qPCR), and 16S ribosomal RNA gene sequencing.
• Included rigorous quality control with positive and negative control samples to mitigate contamination.

Main Results:

• No bacteria or genital mycoplasmas were cultured from amniotic fluid samples.
• qPCR did not detect higher 16S ribosomal RNA gene copy numbers in amniotic fluid compared to controls.
• 16S rRNA gene sequencing showed no significant difference in microbial richness or community structure.

Conclusions:

• Multiple microbiologic methods found no microorganisms in midtrimester amniotic fluid of healthy pregnancies.
• Results suggest that previously reported microbial findings may be due to background contamination.
• This study provides evidence against routine microbial presence in normal amniotic fluid.