In order to navigate the shape of mom's pelvis, babies usually enter the wide oval and rotate clockwise as they pass through. The relative positioning of how the baby's head enters actually impacts the length and difficulty of labor much more than commonly feared issues like the size of the baby. We can compare the head/pelvis to a key fitting in a lock. If it doesn't fit one way, we turn it until it engages. The ideal position for starting labor is for babies to have their backs on mom's left so that as they rotate clockwise through the pelvis, they have to move only 90 degrees and will meet the world facing toward mom's back side. Occasionally babies are born facing toward the front, but they fit more easily facing the back and most rotate into that position during labor.
Babies facing toward the front are said to be 'posterior'. Avoiding this posterior position will help mothers be less likely to experience 'back labor' and shorten and ease the whole labor process. Many women have very successful labors and births despite a posterior baby because the babies are able to turn during the labor process, especially if mom is able to assist by walking and changing positions herself.
But we don't want to make things harder on ourselves than they need to be.
The theory of optimal fetal positioning suggests that indeed we can. We can work with gravity and help to position our bodies in ways that can encourage our little one into a more ideal spot. The head is the heaviest part of the body (which is why most babies turn head-down later in pregnancy) and our postures can help guide our babies to take more labor-friendly positions (i.e. the direction they face). The helpful positions for mom are more upright, (sitting with knees below the hips) or forward leaning (resting on a yoga ball or hands and knees, NOT reclined. Resting lying on your left side is also advisable. You can read some great information about this here www.homebirth.org.uk/ofp.htm#practical and here spinningbabies.com Formal research on this theory is just beginning, but there is a lot of anecdotal evidence that it is effective. So, if you are sitting around counting the days until (or past) your due date, you may consider trying to get your baby to float into a more labor-friendly position.
Maybe scrubbing the floor on hands and knees to start labor could be more than just an old wives' tale . . .
Cindy Crosby is a certified Doula and Childbirth Educator, as well as blogger at www.birth-smart.com. She currently lives with her husband and three children in Derby, Kansas.