Ultrasound Detection of Fetal Palate Development in the Early Stages of the Second Trimester and Its Clinical Application.

Objective: To establish normal values of palatal bone growth in fetuses at different gestational weeks in the early stages of the second trimester and to explore the clinical application value of the four-step ultrasound screening method for fetal cleft lip and palate.

Design: A prospective study of prenatal ultrasound screening.

Setting: Secondary maternal and child health institutions.

Patients: 300 fetuses of 12 to 20⁺⁶ weeks gestation without cleft lip and/or palate; 8538 fetuses at high risk of cleft lip and palate with malformations or karyotypic abnormalities.

Interventions: None.

Main outcome measures: palatomandibular diameter (PMD) and transverse palatal diameter was measured and establish their typical values.

Results: (1) There is a typical "superimposed line" sign in the median sagittal section of the typically developing fetal face from 12 to 20⁺⁶ weeks of gestation. (2) The PMD and hard palate transverse diameter of fetuses from 12 to 20⁺⁶ weeks of gestation increased linearly with time. (3) Among 8538 high-risk fetuses, 21 cases of cleft lip and palate were diagnosed by the four-step ultrasound screening method in the early stages of the second trimester.

Conclusions: The median sagittal section of the typically developing fetal face in the early stages of the second trimester presents a typical "superimposed line" sign, and the PMD and transverse palatal diameter increase with time. The four-step ultrasound screening method for fetal cleft lip and palate in the early stages of the second trimester has high clinical application value.