Maxillary length in euploid and aneuploid fetuses.

Purpose: To examine the maxillary length of euploid and aneuploid fetuses in the second and third trimester.

Methods: Retrospective study utilizing stored 2D images of second and third trimester fetal profiles obtained at the University of Tuebingen, Germany. The length of the maxilla was measured as a straight line between the anterior ventral and posterior ventral edges of the maxilla.

Results: The study population consisted of 347 euploid fetuses and 122, 36, 5, 8, and 4 fetuses with trisomy 21, 18, and 13, Turner syndrome, and triploidy. In the euploid and aneuploid group, mean gestational age was 22.3 and 22.7 weeks, respectively. The maxilla length in euploid fetuses was significantly dependent on gestational age and it was significantly shorter in fetuses with trisomy 21, 18, and 13, and triploidy but not in those with Turner syndrome. In 75.4 and 14.8%, and 11 fetuses with trisomy 21, the maxilla was below the mean, the 5th and 1st centile of the euploid population.

Conclusions: In fetuses with trisomy 21, 18, and 13 and triploidy, the maxilla is significantly shorter, but the difference is only settled, so that it is unlikely that the maxilla length will play a role in second and third screening for aneuploidy.