Part of a fetus which will emerge first upon birth
Presentation of twins inDer Rosengarten ("The Rose Garden"), a German standard medical text formidwives published in 1513
Inobstetrics, thepresentation of afetus about to beborn specifies whichanatomical part of the fetus is leading, that is, is closest to thepelvic inlet of thebirth canal. According to the leading part, this is identified as acephalic,breech, orshoulder presentation. Amalpresentation is any presentation other than a vertex presentation (with the top of the head first).
Relationship of presenting part to maternal pelvis based on presentation. The fetus enters the pelvis in the occipito-transverse plane (left or right), descent, and flexion and then rotates 90 degrees to the occipitoanterior (most commonly).
Left occipitoanterior (LOA)—theocciput is close to the vagina (hence known as vertex presentation), facing anteriorly (forward with mother standing) and toward the left. This is the most common position and lie.
Right occipitoanterior (ROA)—the occiput faces anteriorly and toward the right. Less common than LOA, but not associated with labor complications.
Left occipitoposterior (LOP)—the occiput faces posteriorly (behind) and toward the left.
Right occipitoposterior (ROP)—the occiput faces posteriorly and toward the right.
Occipitoanterior—the occiput faces anteriorly (absolutely straight without any turning to any of the sides)
Occipitoposterior—the occiput faces posteriorly (absolutely straight without any turning to any of the sides)
Face presentation
Mentum anterior—the fetal chin is in the direction of the maternal pubic symphysis.
Mentum posterior—the fetal chin is in the direction of the maternal sacrum. This presentation is not compatible with vaginal delivery.[why?]
Leftsacrum anterior (LSA)—the buttocks, as against the occiput of the vertex presentation, lie close to the vagina (hence known as breech presentation), which lie anteriorly and toward the left.
Right sacrum anterior (RSA)—the buttocks face anteriorly and toward the right.
Left sacrum posterior (LSP)—the buttocks face posteriorly and toward the left.
Right sacrum posterior (RSP)—the buttocks face posteriorly and toward the right.
Sacrum anterior (SA)—the buttocks face anteriorly.
Sacrum posterior (SP)—the buttocks face posteriorly.
Shoulder presentations with transverse lie are classified into four types, based on the location of thescapula (shoulder blade). This presentation needs to be delivered bycesarean section.
^abcKish, Karen; Joseph V. Collea (2003). "Malpresentation & Cord Prolapse (Chapter 21)". In Alan H. DeCherney (ed.).Current Obstetric & Gynecologic Diagnosis & Treatment. Lauren Nathan (Ninth ed.). Lange/McGraw-Hill. p. 369.ISBN0-07-118207-1.
