Fetal Scoliosis: Natural History and Outcomes.

Introduction: Scoliosis can be detected on prenatal ultrasonography and may be associated with structural and syndromic abnormalities. Associations and pregnancy outcomes related to the prenatal diagnosis of scoliosis are poorly understood.

Methods: A retrospective cohort study was undertaken at a tertiary referral center in London. Referred cases with spinal deformities between 1997 and 2021 were identified from the prenatal ultrasonography database. Outcomes were ascertained from the database and electronic notes.

Results: One hundred twenty-three cases of fetal spinal deformities (scoliosis, kyphosis, or kyphoscoliosis) were identified from a referral population of 660,000 pregnancies, giving an incidence of approximately 0.2 per 1000 fetuses. Fifty-eight live births (47.2%) and 65 cases (52.8%) of fetal or neonatal demise or termination were observed. Most live births were isolated spinal deformities with a good postnatal outcome (n = 35, 60.3%). The commonest syndromic diagnosis in this group was VACTERL association (n = 7, 12.1%). Most cases of fetal loss were associated with severe malformations, most commonly spina bifida, body stalk anomaly and amniotic band sequence, or chromosomal abnormalities, except in 2 cases (3.1%).

Conclusions: This is the largest reported cases series to date of prenatally diagnosed fetal spinal deformity. This confirms that fetal scoliosis and associated vertebral abnormalities are underdiagnosed prenatally, with the reported incidence (0.2 per 1000) lower than the recognized incidence of congenital scoliosis (1 in 1,000). The concurrent finding of severe malformations was strongly associated with fetal loss. When an isolated finding, most fetal spinal deformities had a good postnatal outcome, while 1:8 live births were diagnosed with VACTERL association.