Abstract
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.
Keywords
amniotic fluid - ruptured membranes - α
1-microglobulin - ferning
