Fetal micrognathia: Objective assessment and associated anomalies on prenatal sonogram

Objective: To determine the accuracy and characteristics of prenatally detected fetal micrognathia. Methods: A retrospective analysis of all pregnancies with the suspicion of fetal micrognathia was performed. The affected fetuses were reassessed by estimation of the inferior facial angle (IFA) and the frontal nasomental angle on stored gray scale images to objectively establish the diagnosis. Results: Of the 28.935 ultrasounds (USs) reviewed, 58 cases were eligible and 4 were excluded because of inconclusive data. The mean values for IFA and frontal nasomental angle were 44.8° and 123.3°, respectively. In 33 cases, the pregnancy was terminated. Four fetuses died sub partu or immediately after birth, five were stillborn. Invasive testing in 40/54 cases revealed aneuploidies in 35%. Associated anomalies comprised musculoskeletal disorders (43%) and non-skeletal anomalies (15%). Less than one fifth (9/54) were alive beyond postnatal period. Four fetuses had an isolated micrognathia, one of which was found to have a cleft palate postnatally. Conclusion: The diagnosis of micrognathia has a crucial impact on both prenatal and postnatal outcomes of affected individuals due to its association with additional abnormalities. A detailed sonographic survey using objective criteria for defining micrognathia is mandatory. Once the diagnosis is confirmed, an intensive interdisciplinary counseling of the parents is needed.