Clinical Laboratory Experience With Prenatal cfDNA Screening in Triplet Pregnancies

Area of Science:

• Maternal-Fetal Medicine
• Genetics
• Prenatal Diagnostics

Background:

• Cell-free DNA (cfDNA) screening is highly sensitive and specific for common aneuploidies in singleton and twin pregnancies.
• Professional societies endorse cfDNA screening as a first-tier or contingent approach.
• Limited data exists for cfDNA screening performance in triplet pregnancies due to their rarity.

Purpose of the Study:

• To evaluate the performance of cfDNA screening for common aneuploidies in triplet pregnancies.
• To assess the feasibility and outcomes of cfDNA screening in a cohort of triplet gestations.

Main Methods:

• Retrospective review of over 1500 cfDNA screening samples from triplet pregnancies.
• Analysis of screen-positive, screen-negative, and no-result (NR) cases.
• Correlation of cfDNA results with genetic and obstetric outcomes.

Main Results:

• No false positive or false negative results were identified in the analyzed cases.
• 13 screen-positive cases (1.01%) and 270 NR cases (17.32%) were observed.
• Outcome data was available for 147 samples, including all positive cfDNA cases.

Conclusions:

• cfDNA screening is a reasonable option for triplet pregnancies, offering an alternative when other screening methods are unavailable.
• The performance of cfDNA screening in triplets likely mirrors that in twins, with a potentially higher no-call rate.
• Further research may refine cfDNA screening protocols for higher-order multiples.