obstetrics Obstetrics is the field of study concentrated on pregnancy, childbirth and the postpartum period. As a medical specialty, obstetrics is combined with gynecology under the discipline known as obstetrics and gynecology (OB/GYN), which is a surgi ...

, the presentation of a

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...

about to be born specifies which anatomical part of the fetus is leading, that is, is closest to the

pelvic The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

inlet of the birth canal. According to the leading part, this is identified as a

cephalic A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may ...

breech Breech may refer to: * Breech (firearms), the opening at the rear of a gun barrel where the cartridge is inserted in a breech-loading weapon * breech, the lower part of a pulley block * breech, the penetration of a boiler where exhaust gases leav ...

, or

shoulder The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...

presentation. A malpresentation is any presentation other than a vertex presentation (with the top of the head first).

Classification

Thus the various presentations are: *

cephalic presentation A cephalic presentation or head presentation or head-first presentation is a situation at childbirth where the fetus is in a longitudinal lie and the head enters the pelvis first; the most common form of cephalic presentation is the vertex pr ...

(head first): ** vertex (

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

)—the most common and associated with the fewest complications **

sinciput In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp. The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows. The bottom of the fore ...

(forehead) ** brow (eyebrows) ** face ** chin *

breech presentation A breech birth is when a baby is born bottom first instead of head first, as is normal. Around 3–5% of pregnant women at term (37–40 weeks pregnant) have a breech baby. Due to their higher than average rate of possible complications for the ...

(buttocks or feet first): ** complete breech ** footling breech ** frank breech *

shoulder presentation A shoulder presentation is a malpresentation at childbirth where the baby is in a transverse lie (its vertebral column is perpendicular to that of the mother), thus the leading part (the part that first enters the birth canal) is an arm, a shoulde ...

: **arm **shoulder **trunk *compound presentation—when any other part presents along with the fetal head

Related obstetrical terms

Attitude

* Definition: Relationship of fetal head to spine: **flexed, (this is the normal situation) **neutral ("military"), **extended. **hyperextended

Position

* 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). **

Cephalic presentation A cephalic presentation or head presentation or head-first presentation is a situation at childbirth where the fetus is in a longitudinal lie and the head enters the pelvis first; the most common form of cephalic presentation is the vertex pr ...

*** Vertex presentation with longitudinal lie: ****Left occipitoanterior (LOA)—the

occiput The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cereb ...

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. **

Breech presentation A breech birth is when a baby is born bottom first instead of head first, as is normal. Around 3–5% of pregnant women at term (37–40 weeks pregnant) have a breech baby. Due to their higher than average rate of possible complications for the ...

with longitudinal lie: ***Left

sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

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 presentation A shoulder presentation is a malpresentation at childbirth where the baby is in a transverse lie (its vertebral column is perpendicular to that of the mother), thus the leading part (the part that first enters the birth canal) is an arm, a shoulde ...

s with transverse lie are classified into four types, based on the location of the

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...

(shoulder blade). This presentation needs to be delivered by

cesarean section Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or mo ...

. ***Left scapula-anterior (LSA) ***Right scapula-anterior (RSA) ***Left scapula-posterior (LSP) ***Right scapula-posterior (RSP)

Lie

* Definition: Relationship between the longitudinal axis of fetus and mother: **longitudinal (resulting in either cephalic or breech presentation) **oskie (cephalic presentation, fetus legs straight along frontal axis of mother) **oblique (unstable, will eventually become either transverse or longitudinal) **transverse (resulting in shoulder presentation) ***back up ***back down (indication for vertical uterine incision during cesarean delivery)

References

External links

Malpresentations and malpositions: A guide for midwives and doctors
by the

WHO Who or WHO may refer to: * Who (pronoun), an interrogative or relative pronoun * Who?, one of the Five Ws in journalism * World Health Organization Arts and entertainment Fictional characters * Who, a creature in the Dr. Seuss book '' Horton He ...

''Normal Labor and Delivery'' from Management of Labor and Delivery provided by Google books
{{Pregnancy Presentations and positions in childbirth Obstetrics Midwifery