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P20.05: Efficiency and limits of the non‐invasive prenatal genetic testing: a comparative review
Author(s) -
Dimienescu O.,
Liana P.,
Moga M.A.,
Dima L.
Publication year - 2018
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.19781
Subject(s) - trisomy , medicine , prenatal diagnosis , prenatal screening , aneuploidy , fetus , down syndrome , obstetrics , cell free fetal dna , false positive rate , gynecology , pregnancy , genetics , chromosome , biology , statistics , gene , mathematics , psychiatry
Objectives: To examine the relationship of uterine artery pulsatility Index (PI) on the fetal fraction (FF) in maternal plasma cell-free (cf) DNA at 11+0-13+6 weeks of gestation and the possible association with other maternal and fetal characteristics. Methods: This is a cohort study of 1037 singleton pregnancies undergoing at 11–13 weeks of gestation screening by cf-DNA testing for fetal trisomies. CfDNA was extracted from maternal plasma and FF evaluated by the referral laboratory. Uterine artery velocity waveforms were evaluated at the time of maternal sampling by Doppler ultrasonography (WS80 Samsung Medical, Seoul, Republic of Korea) from both uterine arteries and the mean PI calculated. Since uterine artery mean PI changes with gestational age with gestational age, data are expressed as a multiple of the expected median (MoM). Maternal and fetal characteristics considered were maternal age, weight, body mass index (BMI), ethnicity, method of conception, cigarette smoking, fetal Crown–rump length (CRL). Multivariable regression analysis was used to determine significant predictors of the fetal fraction among uterine arteries mean PI MoM and maternal and fetal characteristics. Results: The median fetal fraction was 10.8% (interquantile range [IR] 6.2-15.9%). In 32 women (3.1%) FF resulted < 4%. In such pregnancies uterine artery PI Mom were significantly higher than in those with a FF > 4% (median 1.38; IR 1.05-1.89 vs. 0.98 IR 0.81-1.12 p<0.003). FF decreased with increased mean uterine artery PI MoM, maternal weight, BMI, CRL values and smoking. In multivariable model only maternal weight (p<0.001) and mean uterine PI MoM (p<0.04) resulted significant. Conclusions: FF in maternal plasma cfDNA is affected by maternal weight and uterine artery impedance to flow at 11+0-13+6 weeks of gestation. Uterine artery PI MoM values may have the potential to be incorporated in models to predict the amount of FF to be used in counselling parents concerning the likelihood of failure to obtain a result from cfDNA analysis.