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Updated: May 9, 2026

Isolation of Leukocytes from the Human Maternal-fetal Interface
Published on: May 21, 2015
Second trimester amniotic fluid is reliably fern positive and α1-microglobulin positive: dispelling a labor deck myth
Nicholas S Fogelson1, Paul C Browne2, Stanette Browne3
1Division of Female Pelvic and Reconstructive Surgery, Department of Obstetrics and Gynecology, Emory University School of Medicine, Atlanta, Georgia.
Objective:
Many physicians erroneously believe and have propagated the "myth" that a second trimester amniotic fluid sample will not fern. We attempted to redemonstrate ferning and to demonstrate the efficacy of an assay for α1-microglobulin in second trimester amniotic fluid samples.
Study Design:
Amniotic fluid samples were collected from women undergoing routine genetic amniocentesis between 15 and 26 weeks. A total of 97 samples of second trimester amniotic fluid were placed on slides and examined for ferning at 5 and 10 minutes. An α1-microglobulin assay was performed on each sample. Data were recorded and reported.
Results:
Approximately 93% of samples were fern positive at 5 minutes and 100% were fern positive at 10 minutes. All samples were α1-microglobulin positive.
Conclusion:
Pure amniotic fluid is reliably fern and α1-microglobulin positive in the second trimester. Republication of data only available in pre-online sources will benefit physicians and patients.
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