Fetal mustache in early pregnancy

Area of Science:

• Prenatal diagnosis
• Fetal development
• Medical imaging

Background:

• A rod-like structure on the fetal upper lip, termed a 'mustache,' has been observed as an incidental finding.
• The incidence and clinical significance of this finding require further investigation.

Purpose of the Study:

• To determine the incidence of the fetal upper lip 'mustache' in an unselected population.
• To assess the association of this finding with fetal abnormalities or adverse outcomes.

Main Methods:

• Prospective, non-randomized study involving 3000 fetuses.
• Transvaginal ultrasound examinations at 14-16 weeks' gestation.
• Repeat scans at 20-22 weeks for cases with a 'mustache,' followed by neonatal examination.

Main Results:

• Seven out of 3000 fetuses (0.23%) exhibited a 'mustache'-like structure.
• The structure resolved later in gestation.
• No upper lip anomalies were detected postnatally in affected neonates.

Conclusions:

• The fetal upper lip 'mustache' is likely a normal variant of lip development.
• It may represent a transient delay in embryonic lip fusion.
• The finding does not appear to be associated with adverse outcomes.