Miguel Milan1, Emilia Mateu1, David Blesa1, Monica Clemente-Ciscar1, Carlos Simon2,3,4,5. 1. IGENOMIX S.L., Valencia, Spain. 2. Instituto Universitario IVI, Instituto de Investigación Sanitaria Hospital Clinico de Valencia INCLIVA, Valencia, Spain. 3. Department of Obstetrics and Gynecology, School of Medicine, Valencia University, Valencia, Spain. 4. Fundación Igenomix, Valencia, Spain. 5. Department of Obstetrics and Gynecology, School of Medicine, Stanford University, Stanford, CA, USA.
Abstract
OBJECTIVE(S): We sought to develop an accurate sex classification method in twin pregnancies using data obtained from a standard commercial non-invasive prenatal test. STUDY DESIGN: A total of 706 twin pregnancies were included in this retrospective analytical data study. Normalized chromosome values for chromosomes X and Y were used and adapted into a sex-score to predict fetal sex in each fetus, and results were compared with the clinical outcome at birth. RESULTS: Outcome information at birth for sex chromosomes was available for 232 twin pregnancies. From these, a total of 173 twin pregnancies with a Y chromosome identified in non-invasive pregnancy testing were used for the development of a predictive model. Global accuracy for sex classification in the testing set with 51 samples was 0.98 (95% confidence interval [0.90,0.99]), with a specificity and sensitivity of 1 (95% confidence interval [0.82,1.00]) and 0.97 (95% confidence interval [0.84,0.99]), respectively. CONCLUSION: While non-invasive prenatal testing is a screening method and confirmatory results must be obtained by ultrasound or genetic diagnosis, the sex-score determination presented herein offers an accurate and useful approach to characterizing fetus sex in twin pregnancies in a non-invasive manner early on in pregnancy.
OBJECTIVE(S): We sought to develop an accurate sex classification method in twin pregnancies using data obtained from a standard commercial non-invasive prenatal test. STUDY DESIGN: A total of 706 twin pregnancies were included in this retrospective analytical data study. Normalized chromosome values for chromosomes X and Y were used and adapted into a sex-score to predict fetal sex in each fetus, and results were compared with the clinical outcome at birth. RESULTS: Outcome information at birth for sex chromosomes was available for 232 twin pregnancies. From these, a total of 173 twin pregnancies with a Y chromosome identified in non-invasive pregnancy testing were used for the development of a predictive model. Global accuracy for sex classification in the testing set with 51 samples was 0.98 (95% confidence interval [0.90,0.99]), with a specificity and sensitivity of 1 (95% confidence interval [0.82,1.00]) and 0.97 (95% confidence interval [0.84,0.99]), respectively. CONCLUSION: While non-invasive prenatal testing is a screening method and confirmatory results must be obtained by ultrasound or genetic diagnosis, the sex-score determination presented herein offers an accurate and useful approach to characterizing fetus sex in twin pregnancies in a non-invasive manner early on in pregnancy.
Authors: Hilary Bowman-Smart; Julian Savulescu; Christopher Gyngell; Cara Mand; Martin B Delatycki Journal: Prenat Diagn Date: 2019-10-10 Impact factor: 3.050