Outcome of 45,X fetuses with cystic hygroma: A systematic review

This objective of this systematic review was to estimate live birth rate and explore prognostic indicators in fetuses with 45,X karyotype and a posterior cystic hygroma (CH). Electronic databases were searched and studies reporting pregnancy outcomes (termination, spontaneous abortion, demise, or live birth) for fetuses with 45,X karyotype and a CH diagnosed on ultrasound were included. For cases of survival, CH characteristics, presence of hydrops fetalis, or concomitant anomalies, delivery details, and postnatal outcomes were summarized. A total of 95 studies, including 535 cases, met inclusion criteria: 285 (53.3%) pregnancies were terminated, 72 (13.5%) had spontaneous abortion or demise, 164 (30.7%) had unspecified pregnancy failure, and 14 (2.6%) were live births. Among live births with data available, all CH measured 2-7 cm, more than half were septate, and almost all regressed in size or eventually disappeared. Hydrops fetalis was noted in five cases. Of the eight live births with neonatal outcomes available, three neonates died shortly after birth and five survived past the neonatal period. This review suggests that diagnosis of CH in a 45,X fetus is associated with an estimated live birth rate of 2.6%, but only 1% survive to infancy. Prognosis appears to improve with CH regression.