Many women approaching their birth time ask me about posterior positioning of the baby and how it attribute to the laboring process. Another way to describe posterior presentation is having a baby in the sunny-side-up position during labor and/or birth. This is where the back of the baby’s head (or the heaviest part of the head is resting on the mothers sacrum).
Almost all women have heard some horror story about someone they know who labored with a baby in the posterior position and the extraordinary back pain and extended amount of pushing that came with that kind of positioning. Posterior presentation can be very common in the hospital setting due to epidural anesthetic. In the out-of-hospital or home birth setting we tend to see it much less.
As I approach nearing participating in nearly 500 births, I have noticed a few things about posterior presentation in labor and birth I would like to share with you. In the out-of-hospital setting, where we do not use epidural anesthesia, very rarely a women will birth a baby in the posterior presentation. In fact, I have only seen 2 birth where the baby came out sunny-side-up or looking towards the vulva. Neither posterior presentations was a problem at all for the women who birthed them. Both the labor and birth process was straight forward, no interference to the fetal-ejection-reflex, the baby came out with ease during pushing and no extraordinary back pain was present. Both women birthed a baby between 5 – 7.5lbs, which I consider on the smaller side of normal birth weight for the term babies in my practice.
In most cases, if a baby favors the posterior position they will favor that position the weeks leading up to going into labor. For babies that settle into the pelvis in the posterior position labor will likely come and go for a matter of days creating a laboring pattern called prodromal or false labor. This means that regular contractions are happening, fairly strongly but they are inconsistent, uncoordinated coming sometimes every 10mins apart, sometimes every 5mins and other times every 20 mins apart. These contractions can be long lasting 60-90 secs at a time and get stronger when the mother is moving around. However, prodromal labor doesn’t move the baby down and the cervix does not open.
This kind of laboring pattern is often always linked to the baby favoring a posterior presentation and thankfully it can be fairly easy to stop this kind of laboring pattern. Ways to stop prodromal labor patterns include by taking long showers or baths, oral therapeutic dose of magnesium aspartate or orotate, techniques that facilitating a quiet body, mind , spirit, herbal teas, Diphenhydramine can help, melatonin and the essential amino acid L-tryptophan. It is always my recommendation, to rest and facilitate sleep until active labor. By chasing contractions away, eventually the baby will move out of the posterior position and the body will eventually kick into active labor and the mother can go on to have a straight forward physiological birth.
Many women worry about having back pain during labor in relation to a baby being in posterior positioning. Back labor is the hallmark sign of posterior positioned babies. However, back pain is also a normal part of birthing as the baby begins to push themselves through the pelvic bones and the sacrum has to flex in order for the baby’s head to pass under the pubic bone.
Posterior positioning can be a common finding for women on epidurals due to the lack of movement response and neuromuscular response due to the anesthetic. Anesthetic epidurals help the muscles to go completely slack and the woman is no longer able to respond to labor in the normal way of getting up and down to empty bladder, moving from hands and knees to standing, L-side lying, walking or getting in and out of the tub. With the combination of muscle release and becoming sedentary in labor, the baby is more likely to turn to the posterior position and to get stuck in the pushing phase as it is very difficult for the baby to extend its head during the final cardinal movement to produce crowning. This often leads to long 3-4 hr pushing phases on an epidural. Babies born via epidural births DO eventually rotate to the Occipital Anterior to finally be born. However, it takes extra energy reserves on the baby. Long labors and pushing phases increases the risk of cesarean birth as babies can end up getting tired and distresses when having to navigate posterior birth. However, even with epidural birth the baby almost always comes out OA.
The best way to avoid posterior birth is to avoid sitting or sleeping in recliners or in the reclining position. Left or Right siding laying for sleep is preferred, gentle physical activity like walking and swimming up until labor are great ways to ensure your baby avoids posterior presentation. Facilitate therapeutic rest if labor comes and goes strongly. Don’t waste your time with trying to facilitate stronger contractions when you can chase them away. There is nothing you can do to active labor come any faster and there’s nothing you can do to make active labor go away! Patience, rest and do what you can to make contractions space out or go away. Conserve the uterine energy and either the force of true active labor will help the baby to turn or the baby will reposition themselves and then active labor will come.