What is brow presentation?

Brow presentation occurs when the fetal head is in partial extension, with the brow or forehead leading through the birth canal. This position lies between complete flexion (vertex presentation) and full extension (face presentation). It is clinically significant because it often leads to a wider diameter of the presenting part, making vaginal delivery difficult or impossible. Recognition of brow presentation is crucial for planning delivery method and preventing complications such as obstructed labor.

Reference: Williams Obstetrics, Cunningham FG, 25th Edition.