Delivery presentation describes the way the baby (fetus) is positioned to come down the birth canal for delivery.
Your baby must pass through your pelvic bones to reach the vaginal opening. Certain positions result in a smaller area and shape for the baby to pass through this tight passage.
The best position for the baby to pass through the pelvis is with the head down and the body facing towards the mother’s back. This position is called occiput anterior (OA).
In breech position, the baby's bottom is facing down instead of the head. Other delivery presentations can also cause problems. Your doctor may not notice some problems until you are already in labor.
Occiput Posterior (OP)
Your baby’s head is down, but is facing the wrong way. The baby faces the mother’s front instead of her back.
It is safe to deliver the baby when it faces this way. But it is harder for the baby to get through the pelvis. If a baby is in this position, sometimes it will rotate around during labor so that the baby’s head is down, and the body is facing the mother’s back (OA position). The mother can walk, rock, and try different delivery positions during labor to help encourage the baby to turn. If the baby does no turn, labor can take longer. Sometimes the doctor may use forceps or a vacuum device to help get the baby out.
A baby in the transverse position is sideways. Often, the shoulders or back are over the mother’s cervix. This is also called the shoulder, or oblique, position.
The risk for having a baby in the transverse position increases if you:
Go into labor early
Have given birth five or more times
Have placenta previa
Unless the baby can be turned into head-first position, a vaginal birth would be too risky for you and the baby. Your doctor will deliver the baby by C-section.
Less Common Presentations
With the brow-first position, the baby's head extends backward (like looking up), and the forehead leads the way. This position may be more common if this is your second pregnancy. It may also occur if you have had more than two pregnancies.
Your health care provider rarely detects this position before the birth. An ultrasound test may be able to confirm a brow presentation.
More likely, your health care provider will detect this position when your labor is not progressing well, during an internal exam.
With face-first position, the baby's head is extended backwards even further than with brow first position.
Most of the time, the force of contractions causes the baby to be in face-first position.
It is also detected when labor does not progress.
In some of these cases, a vaginal birth is possible, but labor will generally take longer. After delivery, the baby’s face or brow will be swollen and may appear bruised. These changes will go away over the next few days.
Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.