Posterior Arrest often occurs at around 6 centimeters dilation as the baby's head descends through the pelvis in a posterior position. The hard back of the head gets caught against the sacrum, forcing the chin to deflex and the forehead to point downward to the cervix. In this position, the head often rests against the pubic bone, causing cervical edema. And because the forehead does not apply the proper pressure to the cervix, dilation often stops.
The first thing to try is different positions...squatting, hands-and-knees....by allowing a little extra space in the pelvis, the head might go ahead and rotate. However, with the chin deflexed, this will be difficult. If there is no progress in these positions, you might try knee-chest, and this little manipulation.
In the knee-chest
position, reach your hand down to see if you can feel the baby's
If so, you should be able to feel the anterior fontanelle on the part
your baby's head that is facing toward the front of your body.
pressure to the fontanelles. However, you can apply pressure just
above the fontanelle, on the bony edge. Now picture in your mind
that you are dialing a telephone. You can do this yourself, or
a helper do it. You put two fingers just on the bony edge of the
anterior fontanelle, and dial to your left. By this, I mean exert
pressure to the left and inward. This should help flex the head
rotating to a transverse position. After it has rotated to
and you have flexed the anterior fontanelle until it is almost out of
reach, move your fingers to the posterior fontanelle, which should now
be in your reach. Do the same movement - dialing to the left and
inward. Now, try to hold the head in place while you get
I know, this is an awkward movement. Perhaps someone can help you
up. See if the head stays in place through the next couple of
and descends and/or rotates. If you continue to see descent of
head, you have been successful. However, it make take two or
times of repeating this rotation exercise in order for the head to
enough that it will stay in place.
Back to Handling Variations of Normal
to The Online Childbirth Class
Judie C. Snelson and The Center for Unhindered Living