Twenty-seven studies were included in the review (more than 2,055,624 participants): 21 in low-risk populations (more than 2,005,173 participants, range 1,856 to 709,030 where reported) and six in high-risk populations (n=451, range 21 to 216). Ten studies were retrospective and 17 were prospective.
Low-risk women: Retrospective cohort studies (seven studies) reported prenatal detection rates that ranged from zero to 70% for all types of cleft, 33% to 88% for cleft lip with or without cleft palate and zero to 22% for cleft palate. Prospective cohort studies (14 studies) reported detection rates that ranged from 9% to 73% prenatally for all types of cleft, 9% to 100% prenatally for cleft lip with or without cleft palate and zero to 7% post-natally for cleft palate.
High-risk women: One of three retrospective cohort studies reported a detection rate of all types of cleft of 41% for unilateral clefts and 44% for bilateral cases. The second study reported a rate of cleft lip with or without cleft palate of 87% for unilateral clefts and 66% for bilateral clefts, and a rate for cleft lip with cleft palate of 88% for unilateral clefts and 90% for bilateral clefts. The third study reported a rate of cleft lip with or without cleft palate of 31% for unilateral clefts and 20% for bilateral clefts.
The three prospective cohort studies reported detection rates of cleft lip with or without cleft palate that ranged from 91% to 96% for 2D ultrasound and 100% for 3D. In two studies, rates of cleft lip with cleft palate were 41% and 46% for 2D ultrasound and 86% and 90% for 3D. One study reported detection rates for cleft palate only of 22% for 2D ultrasound and 89% for 3D.