Occiput Anterior, or OA
The ideal position for birth, associated with the fewest complications, is the occiput anterior position. In this position, the occiput, or rear part of the baby's skull, is facing away from the mother's spine. This is the easiest position for labor because it places the soft part of the baby against the mother's spine. This helps labor to progress more smoothly, quickly, and painlessly than other positions, and it is also associated with fewer complications.
There are variations of the occiput anterior position:
Left Occiput Anterior, or LOA
The left occiput anterior position differs slightly from the occiput anterior position. It indicates that the baby is facing slightly toward the mother's right leg (with his occiput facing her left buttocks). This is also a good position for labor and is associated with few complications.
Right Occiput Anterior, or ROA
Another easy and common position, right occiput anterior fetuses are generally delivered without complication. In this position, the baby is turned slightly so that he is facing the mother's left side, with the back of his head facing the mother's right buttocks.
Occiput Transverse
Many fetuses are in a left occiput transverse or right occiput transverse position in early labor. In this position, the baby is fully facing his mother's left or right side. In general, the baby will turn to an occiput anterior position as labor progresses. If the baby does not turn into an occiput anterior position, labor may stop or slow, and this is sometimes solved by forceps or vacuum extraction. Cesarean sections sometimes occur when a fetus is in a persistent left or right occiput transverse position.
Right Occiput Transverse, or ROT
A baby in this position is facing his mother's left side, with the back of his skull against her right side. It can be difficult or painful to vaginally deliver a baby who will not turn from this position.
Left Occiput Transverse, or LOT:
As with a right occiput transverse position, the left occiput transverse position may be complicated without intervention. A fetus in a left occiput transverse position is facing his mother's right leg, with his occiput to her left.
Occiput Posterior, or OP
This is an undesirable position for labor and delivery, but it occurs in about one-quarter of all births. A baby in an occiput posterior position has his occiput against his mother's spine, and he is facing her belly. Although fetuses in an occiput posterior position can be delivered without complicaction, labor is often associated with severe back pain ("back labor"), may increase the likelihood of vaginal tearing, and often takes longer to progress. This is because the occiput posterior position places the hardest part of the baby--his spine--against the mother's backbone. Some obstetricians and midwives use forceps to deliver babies in an occiput posterior position, but this is controversial.
There are variations of the occiput posterior position:
Left Occiput Posterior, or LOP
In this position, the fetus' occiput is facing slightly to the left, with his face toward the mother's right leg. It carries the same complications as the basic occiput posterior position.
Right Occiput Posterior, or ROP
Like the basic and left occiput posterior positions, the right occiput posterior position can be painful and might be associated with complications. Fetuses in a right occiput posterior position are facing their mothers' right leg, with their occiputs against her left buttocks.
Although there are some complications associated with a few versions of the cephalic position, the fact that the fetus is presenting head-first is more than half the battle in guaranteeing a safe and healthy delivery. My own daughter, who decided to come out sunny-side up (occiput posterior) was still born drug-free, forceps-free, quickly, and with no complications. The exact presentation of a cephalic-position fetus is not generally known until labor, but a doctor or midwife may palpate a pregnant woman's uterus to guess the position of the baby. In some cases, an ultrasound may be prescribed to confirm the position.