目的   探讨孕中晚期口腔二维轴向切面超声在产前诊断胎儿唇腭裂中的应用价值，评估其对唇裂、唇腭裂及继发腭裂的检出率和准确性。方法   本研究为前瞻性研究，共纳入2020年3月—2023年12月在我院超声科行产前超声诊断的3 666例孕中晚期胎儿，其中经超声检查诊断出111例唇腭裂，这些病例归为唇腭裂组，其余3 555例归入正常对照组。所有受试者均通过口腔二维轴向切面超声进行评估，诊断结果经产后随访确认。结果   在正常对照组中，上唇及上牙槽突的评估成功率为100%，软硬腭分界线显示率为99%，软腭显示率为85%。在唇腭裂组中，超声对唇裂、唇腭裂及继发腭裂的检出率分别为45%、48%和7%，且超声诊断的灵敏度、特异度和预测值均超过98%。结论   孕中晚期口腔二维轴向切面超声在产前诊断胎儿唇腭裂中具有较高的准确性和可靠性，为早期干预和临床管理提供了重要的影像学依据。

       Objective  To explore the application value of two-dimensional axial section ultrasound in prenatal diagnosis of fetal cleft lip and palate in the second and third trimesters of pregnancy，and to evaluate its detection rate and accuracy for cleft lip，cleft lip and palate，and secondary cleft palate．Methods  This study is a prospective study that included 3 666 fetuses in the second and third trimesters of pregnancy．Among them，111 cases of cleft lip and palate were diagnosed by ultrasound examination．These cases were classified as the cleft lip and palate group，and the remaining 3 555 cases were classified as the normal control group．All subjects were evaluated by oral two-dimensional axial section ultrasound，and the diagnostic  results were confirmed by postpartum follow-up．Results  In the normal control group，the success rates of evaluating the upper lip and upper alveolar process were 100%．The present rate of the soft hard palate boundary was 99%，and the present rate of the soft palate was 85%．In the cleft lip and palate group，the detection rates of cleft lip，cleft lip and palate，and secondary cleft palate by ultrasound were 45%，48% and 7% respectively，and the sensitivity，specificity，and predictive value of ultrasound diagnosis exceeded 98%．Conclusions  Two dimensional axial section ultrasound of the oral cavity in second and third trimesters of pregnancy has high accuracy and reliability in prenatal diagnosis of fetal cleft lip and palate，providing strong imaging evidence for early intervention and clinical management．