Premaxillary-maxillary suture development in the first trimester : An ultrasound study.

Abstract

Our study was designed to investigate premaxillary-maxillary suture growth in fetuses from the first trimester of pregnancy using the B‑ultrasound technique in order to determine the suture fusion time. We selected 169 healthy Han singleton pregnancies as subjects. All subjects received routine pregnancy tests and were divided into three groups based on the gestational age of the fetus: group1, the 11th gestational week; group2, the 12th gestational week; and group3, the 13th gestational week. Fetal biometric measurements were recorded during consecutive prenatal ultrasonographic examinations. These measurements included nuchal translucency thickness, crown-rump length, and premaxillary-maxillary length. Intergroup comparisons were performed using analysis of variance (ANOVA). The premaxillary-maxillary suture grows gradually and its measured length at the 11th, 12th and 13th week was 0.54 cm, 0.65 cm, and 0.74 cm, respectively. We observed asignificant linear correlation between the premaxillary-maxillary length and the week of gestation in the first trimester. The growth rate of the maxilla at the 11th, the 12th and the 13th week are significantly different with adescending order of growth rates being week12, week11 and week13, with the 12th week rate being the most rapid. The premaxillary and maxillary growth at 11 and 12 gestational weeks in the first trimester steadily accelerated, peaking at the 12th week. The rate of growth slows down after week 12 which may be associated with the fusion of the premaxillary-maxillary suture.