Position (obstetrics)
In obstetrics, position is the orientation of the fetus in the womb, identified by the location of the presenting part of the fetus relative to the pelvis of the mother. Conventionally, it is the position assumed by the fetus before the process of birth, as the fetus assumes various positions and postures during the course of childbirth.
Positions
Depending upon which part of the fetus is expected to be delivered first, there are many possible positions:- Vertex presentation with longitudinal lie:
Name | Abb. | Description |
Left occipitoanterior | LOA | occiput, as against the buttocks, is close to the vagina faces anteriorly and towards left. This is the most common position and lie. |
Right occipitoanterior | ROA | occiput faces anteriorly and towards right. Less common than LOA, but not associated with labor complications. |
Left occipitoposterior | occiput faces posteriorly and towards left. | |
Right occipitoposterior | ROP | occiput faces posteriorly and towards right. |
Occipitoanterior | occiput faces anteriorly | |
Occipitoposterior | occiput faces posteriorly | |
Left occipitotransverse | LOT | occiput faces left |
Right occipitotransverse | ROT | occiput faces right |
- Breech presentation with longitudinal lie:
- Left sacrum anterior —the buttocks, as against the occiput of the vertex presentation, like close to the vagina, which lie anteriorly and towards the left.
- Right sacrum anterior —the buttocks face anteriorly and towards the right.
- Left sacrum posterior —the buttocks face posteriorly and towards the left.
- Right sacrum posterior —the buttocks face posteriorly and towards right.
- Sacrum anterior —the buttocks face anteriorly.
- Sacrum posterior —the buttocks face posteriorly.
- Shoulder presentation with transverse lie are classified into four types, based on the location of the scapula ; note: the presentation is significantly different from asynclitic positioning, and in most cases needs to be delivered by cesarean section.
- Left scapula-anterior
- Right scapula-anterior
- Left scapula-posterior
- Right scapula-posterior