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Occipitoposterior Position: The occiput is in the posterior segment of the pelvis, overlying the sacroiliac joint or the sacrum. It is responsible for most cases of prolonged labour and second stage delay.

Engaging Diameters

  1. Suboccipitofrontal diameter in a deflexed head".
  2. Occipitofrontal diameter in a head which is further deflexed",

Course of Labour:

  1. Anterior rotation: In 90% of cases, the occiput rotates anteriorly through 3/8 of a circle and the baby is born as occipitoanterior. Engagement may be delayed and labour may be longer because of deflexion.
  2. Posterior rotation and face to pubis delivery: When the head is deflexed, the engaging diameter is the occipitofrontal and the sinciput is the leading part. hence, the sinciput touches the pelvic floor first and rotates anteriorly. The occiput thus rotates posteriorly into the hollow of sacrum and delivery occurs as face to pubis.

Most common complication in such cases is Perineal teers" as the occiput is posterior and it is the longer biparietal diameter (9.4 cm) which distends the perineum rather than the smaller bitemporal diameter (8 cm). Hence in all such cases a liberal episiotomy should be given.

Besides this due to extreme moulding there is elevation of falx cerebrii which favours tentorial tear.
Occipitosacral position and face to pubis delivery are more common in an anthropoid pelvis.

Sometimes: There is failure to progress (arrest) inspite of good uterine contractions for about %-1 hr after full dilatation of the cervix- This is occipito sacral arrest.


Management of Occipito sacral arrest:

If head is engaged and occiput is below ischial Spines - Forceps application in un rotated head followed by extraction as face to pubis.


If occiput remains at or above the level of ischial spine - Cesarean section.


  1. Failure of Rotation:
    Persistent occipito posterior position.

Partial anterior rotation → Head is arrested with saggital suture in transverse diameter at the level of ischial spine, after full dilatation inspite of good uterine contractions called as Deep Transverse Arrest.


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