Optimal Fetal Positioning
Childbirth educator Pauline Scott coined the phrase Optimal Fetal Positioning to describe the work of Midwife Jean Sutton. These two women published Understanding and Teaching Optimal Fetal Positioning in 1996. Two facts will help you to understand why fetal position is important:
- Baby's rotate to come from the womb through the pelvis and out.
- Fetal position effects fetal rotation and descent.
Optimal Fetal Positioning aims to help a fetus into the easiest birth positions for labor by giving the mother guidelines for her posture and movement (maternal positioning) in pregnancy and during labor.
Many studies show that posterior labors are more complicated for mother and baby-in general. Of course, some women do have short and rather easy posterior births. But, more posterior labors end in cesarean delivery compared to anterior labors. And, birthing a posterior positioned baby can take much longer than an anterior baby due to how fetal position effects labor.
The angle of the baby's head changes the diameter of the head.
So that a baby facing the mother's back most often fits the pelvis more easily than a baby who faces the front. The back of baby's head is the landmark (occiput bone):
The baby facing mother's back is in the "anterior" position because the baby's occiput is towards mother's anterior (front).
The baby facing mother's front is in the "posterior" position because the occiput is towards mother's back.
The baby facing the right hip and coming into the pelvis from the left fits more easily than the baby whose back is on the mother's right.
Now this last detail is a clue. If the pelvis was the only factor in fetal positioning concerns, then left and right would simply be mirror images and of equal ease (or challenge) during birth. But Midwife Jean Sutton reminds us that other anatomical features play a part in fetal position.
The mother's liver and spine can make the baby's whose back is on the right have a more extended chin. This puts the top of the head at the pelvic brim. The top of the head is longer than the crown of the head. The baby can't help with the birth as well as the baby whose chin is tucked close to the chest.
The optimal fetal positions are considered to be:
- Left Occiput Transverse (Left Occiput Lateral, top circle)
- Left Occiput Anterior (middle circle)
- Occiput Anterior (bottom circle)
The baby in the Right Occiput Anterior position may or may not be optimal:
The Right Occiput Anterior (Right Occiput Lateral) baby may have to rotate further to the left to fit through the pelvis
The ROT/ROL baby may be more likely to have his or her chin up making the head circumference larger than with the chin tucked.
Both of these two maybes, may increase the chance of the ROT/ROL baby needing more interventions for birth. A first time mother may have a longer labor with a Right Occiput Anterior baby than she would with a Left Occiput Transverse baby when rotation is effected by fetal position. If flexion is good, and the mother's pelvic floor is relatively balanced, the ROT/ROL baby probably won't present any problems at all.
More on fetal positions and how they effect labor in The Belly Mapping Workbook or the Belly Mapping article on this site.
Jean Sutton advises good maternal posture to help baby settle in an optimal position. She suggests positions that keep the pelvic brim open - away from the spine. Good posture includes standing and letting your belly hang freely to be a hammock for the baby and sitting up and letting your belly come forward. Pauline Scott discusses Jean Sutton's recommendations in Sit Up and Take Notice. Janet Balaskas wrote the book inspiring Jean and Pauline's exciting information, Active Birth.
Spinning Babies approaches Optimal Fetal Positioning with more focus on the mother's body balance than her posture.
Posture is important, I agree. I describe potentially good maternal postures in Rest Smart. Good posture will help a baby into a more optimal position unless there is a twist or significant tightness in the broad ligament, pelvic floor, or other soft tissues of the mother's reproductive anatomy. In other words, some women need more than gravity to help the baby into a good position. That's why I start with Balance as the first Principle of Spinning Babies, and have Gravity as the second principle.
Jean Sutton's little book has become the diving board for my life's work. Its amazing to me how the circle widens. I didn't see this coming in my life. I thought I'd like to be a paperback writer!
Amy Hoyt has a series on Optimal Fetal Positioning with great photos on her blog: Natural Birth in Kitsap
