This retrospective case-controlled study analysed the outcome of pregnancies with first-trimester enlarged nuchal translucency (NT) and a normal karyotype. A total of 479 pregnancies with first-trimester NT measurements were grouped as control (370 cases; normal NT) and study (109 cases; enlarged NT, ≥95th percentile; with normal karyotype). Adverse outcomes included miscarriage, intrauterine foetal death, termination of pregnancy, neonatal death, and structural/chromosomal/genetic abnormalities. The study was conducted between June 2016 and June 2022 at the Foetal Maternal Unit of Kanad Hospital, UAE. Overall, the live birth rate in the study group was significantly lower (74.3%) compared to the control (94.1%, p < 0.001). All pregnancy outcomes of this group significantly differed compared to the control. The observed miscarriage level was 9.2% (vs. 1.1%, p < 0.001), intrauterine foetal death was 2.8% (vs. 0%, p = 0.001), spontaneous preterm birthwas 11% (vs. 4.9%, p = 0.020), and termination of pregnancy was 3.7% (vs. 0%, p < 0.001). The presence of foetal abnormalities was also significantly higher in the enlarged NT group at 21% (vs. 3.3%, p < 0.001). Results indicate that enlarged NT is associated with adverse pregnancy outcomes even when the karyotype is normal. Based on these results, a comprehensive review of the guidelines for counselling and managing pregnancies with enlarged NT and a normal karyotype is recommended.
Keywords: amniocentesis; chorionic villus sampling; congenital anomalies; enlarged NT; karyotype; microarray; nuchal translucency; perinatal outcomes.