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Prematurity

Poster Session 2

(505) Evaluating the Detection of Ferning with Previable Rupture of Membranes

Tuesday, February 13, 2024
3:30 PM – 5:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective:

To evaluate the impact of gestational age and drying time on the detection of ferning in vaginal amniotic fluid samples from second trimester pregnancies with rupture of membranes (ROM). Additionally, to evaluate if the use of a centrifuge for removal of red blood cells would improve the detection of ferning.

Study Design:

A prospective study evaluating vaginal amniotic fluid in individuals undergoing pregnancy termination between 15-24 weeks from 8/1/2021 to 6/9/2023 at a single institution. A control vaginal swab was collected prior to ROM and a sample vaginal swab was collected after ROM at the time of the termination procedure. A 10-ml sample of amniotic fluid was also collected and centrifuged for removal of red blood cells. All samples were analyzed and images captured under a microscope using 10x magnification at 1, 5, 10, 15 and 20 minutes after ROM. Images were assessed for ferning by two blinded investigators with a third reviewer in the case of any discrepancies. Statistical analysis was performed using descriptive statistics and regression analyses.

Results:

A total of 99 individuals consented and 93 were included. The mean gestational age was 19.5 weeks (2.6 STDEV). Ferning was not seen during any time point in a total of 14 cases (15.1%). None of the control samples had ferning detected. The detection of ferning increased with longer drying time in a regression analysis (OR 1.2; 95% CI 1.17-1.25). The largest difference was observed between 1 and 5 minutes (25.8% at 1 minute versus 73.1% at 5 minutes). Gestational age did not impact the detection of ferning (OR 1.06; 95%CI 0.98-1.15, p=0.099). Overall, ferning was detected more frequently on centrifuged samples than vaginal at all time points (Figure 1).

Conclusion:

Both drying time and blood impacted the detection of ferning with previable ROM. Optimal detection was seen after allowing drying for 5 minutes and with centrifuge for the removal of red blood cells. These findings may improve the detection of ferning in suspected cases of previable ROM.