Malpresentations and Positions & Operative Obstetrics
Occipito posterior position in labour management is (AIIMS Nov. 2009)
|B||Artificial rupture of membranes|
|C||Wait and Watch|
Wait & Watch
Occipito posterior position
1. Definition:The occipital region of the head lies in the right or the left side at the back of the uterus either over the sacroiliac joint or directly over the sacrum.
a. This is the most common malposition.
b. At the onset of labour incidence of OP is around 10-11%. LOP (left occipito-posterior): 3 per cent or ROP (right occipito-posterior): 8 per cent.
c. LOP is more likely to be associated with complications.
a. Faults in the passage (pelvic cavity):
Anthropoid pelvis; OP position is associated with a pelvis in which AP diameter exceeds the transverse diameter. In this pelvis with high assimilation type, extra vertebra is included in the formation of the sacrum.
Pelvis with wedge shaped brim; as bulky occiput cannot find room in the pinched forepart of the pelvis.
b. Faults in the passenger (baby):
c. Faults in power i.e. the uterine inertia.
Abnormal uterine contractions leading to persistent deflexion.
a. Per abdominal:
i. Abdomen looks flat below umbilicus.
ii. Fetal limbs easily felt near the midline.
iii. Back felt away from the midline.
iv. Anterior shoulder away from the midline.
v. FHS on the flank, difficult to locate.
b. Per vaginal:
i. Early labour.
1) Early rupture of membrane.
2) Anterior fontanalle more easily felt and at a lower levels.
ii. In late labour:
1) Caput and unfolded pinna points towards the occiput.
4. Occipito posterior has the following behaviour in labour
a. Almost 80% of cases it can undergo anterior 3/8th rotation at the pelvic floor and deliver as occipito anterior
b. In 15-20% cases it stays occipito posterior and delivers as face to pubis
c. In rare cases it can rotate insufficiently and get stuck in Deep transverse arrest in an android pelvis, which is best managed in modern obstetrics by manual rotation and forceps extraction. If this is associated with fetral distress then a cesarean section is best