(1128) Mid-trimester concentrations of total cell-free DNA in amniotic fluid – A pilot study

Friday, January 31, 2025

4:00 PM – 6:00 PM

Coauthor(s)

DT

Dan Tirosh, MD

Department of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev
Beer Sheva, HaDarom, Israel
AD

Amos Douvdevani, PhD

Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Soroka University Medical Center, Ben-Gurion University of the Negev
Beer-Sheva, HaDarom, Israel

Submitting Author and Presenting Author(s)

NB

Neta Benshalom-Tirosh, MD (she/her/hers)

Department of Obstetrics and Gynecology, Samson Assuta Ashdod University Hospital; Faculty of Health Sciences, Ben-Gurion University of the Negev
Ashdod, HaDarom, Israel

Coauthor(s)

OE

Offer Erez, MD

Department of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev
Beer Sheva, HaDarom, Israel
JB

Joel Baron, MD

Department of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev
Beer Sheva, HaDarom, Israel

Objective: 1) To test the feasibility of measuring total cell-free DNA (cfDNA) concentration in amniotic fluid, using a unique direct fluorometric assay; and 2) to determine the association between amniotic fluid total cfDNA concentration and gestational age at amniocentesis, establishing reference values for further studies.

Study Design: A prospective cohort pilot study was conducted, including women undergoing elective mid-trimester amniocentesis for genetic or other evaluation, between 16-23 weeks of gestation. Following written consent, an additional 1-2 ml of amniotic fluid were collected during amniocentesis. Total cfDNA was quantified by a validated rapid fluorometric assay, using the fluorochrome SYBR® Gold without requiring prior DNA extraction and amplification.

Results: A total of 82 women were enrolled. Seventy-seven women were included in the analysis, as five were excluded due to preterm delivery (n=4) or a genetic disorder (x-linked ichthyosis, n=1). All samples had measurable total cfDNA concentrations. Maternal characteristics including indications for amniocentesis are presented in Table 1. Total cfDNA concentrations correlated significantly with gestational age at sample collection (rho=0.41, p value< 0.001), as presented in Figure 1.

Conclusion: 1) Total cfDNA amniotic fluid concentrations in the mid-trimester, correlate with gestational age at sampling; 2) This simple assay enables rapid quantitative measurements, and thus should be further evaluated as an amniotic fluid biomarker for obstetric complications.