Detection of triploid, molar, and vanishing twin pregnancies by a single-nucleotide polymorphism-based noninvasive prenatal test.
Am J Obstet Gynecol
; 212(1): 79.e1-9, 2015 Jan.
Article
in En
| MEDLINE
| ID: mdl-25447960
ABSTRACT
OBJECTIVE:
We sought to determine the ability of single-nucleotide polymorphism-based noninvasive prenatal testing (NIPT) to identify triploid, unrecognized twin, and vanishing twin pregnancies. STUDYDESIGN:
The study included 30,795 consecutive reported clinical cases received for NIPT for fetal whole-chromosome aneuploidies; known multiple gestations were excluded. Cell-free DNA was isolated from maternal blood samples, amplified via 19,488-plex polymerase chain reaction, and sequenced. Sequencing results were analyzed to determine fetal chromosome copy number and to identify the presence of additional fetal haplotypes.RESULTS:
Additional fetal haplotypes, indicative of fetal triploidy, vanishing twin, or undetected twin pregnancy, were identified in 130 (0.42%) cases. Clinical confirmation (karyotype for singleton pregnancies, ultrasound for multifetal pregnancies) was available for 58.5% (76/130) of cases. Of the 76 cases with confirmation, 42.1% were vanishing twin, 48.7% were viable twin, 5.3% were diandric triploids, and 3.9% were nontriploid pregnancies that lacked evidence of co-twin demise. One pregnancy had other indications suggesting triploidy but lacked karyotype confirmation. Of the 5 vanishing twin cases with a known date of demise, 100% of losses occurred in the first trimester; up to 8 weeks elapsed between loss and detection by NIPT.CONCLUSION:
This single-nucleotide polymorphism-based NIPT successfully identified vanished twin, previously unrecognized twin, and triploid pregnancies. As vanishing twins are more likely to be aneuploid, and undetected residual cell-free DNA could bias NIPT results, the ability of this method to identify additional fetal haplotypes is expected to result in fewer false-positive calls and prevent incorrect fetal sex calls.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Prenatal Diagnosis
/
Hydatidiform Mole
/
Polymorphism, Single Nucleotide
/
Triploidy
/
Fetal Resorption
/
Pregnancy, Twin
Type of study:
Diagnostic_studies
/
Prognostic_studies
Limits:
Adolescent
/
Adult
/
Female
/
Humans
/
Middle aged
/
Pregnancy
Language:
En
Journal:
Am J Obstet Gynecol
Year:
2015
Type:
Article
Affiliation country:
Canada