When you see these diagrams of an opening cervix, you can see how a posterior lip would be unlikely because in actuality, the cervix opens in an elliptical fashion and not concentrically. The baby’s head dilates the cervix more with each contraction pulling the anterior part of the cervix with it. When the head is not centered evenly on the cervix, one side may dilate more than the other resulting in an anterior lip.
Wikipedia defines an anterior lip as: “The anterior section of the cervix is nearly always the last part of the woman’s cervix to be finally taken up into the lower segment of the uterus. An anterior lip occurs when the top of the cervix swells, but the rest of the cervix has completely dilated. An anterior lip can slow the woman’s progress from the 1st to 2nd stage of labor, because the swelling will usually take time to reduce, before enabling the woman’s cervix to be pulled up, and around, the baby’s head.” concentric
Women are frequently told they may have a swollen anterior lip that is impeding progress in labor. What can a woman in labor do?
- Try to push through the cervix but only if she feels an urge to push. When the cervix simply isn’t ready it can just become more swollen.
- Changing positions a lot throughout labor will help to avoid malpositions. Position changes will help keep the baby moving and rotating into optimal positions so the baby’s head will be presented evenly on the cervix. Upright positions or hands and knees are best. Try lunges, trunk rotation, walking up and down steps or marching in place, rocking the pelvis, or hanging from a rope. Using a rebozo can give even more sway to the hips when used to make a figure eight in a standing position.
- Some midwives will place an ice cube on the lip and leave it there for a few minutes. They say this works every time for them.
The woman who was told she had a posterior lip – well, it just shows we have to be informed consumers.