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StorkNet's Week By Week Guide to Pregnancy
Posterior Labor - A Pain in the Back!
Its Prevention and Cure
by Valerie El Halta, CPM
I have become increasingly frustrated and angered that posterior presentation (back of the baby's head toward the mother's back) and its ensuing complications in labor and delivery have accounted for an inordinate number of cesarean sections. Many of the women who come to us desiring VBACs have suffered a previous cesarean for "failure to progress" and "CPD" (cephalo-pelvic disproportion) and yet, when we receive the woman's records, the post-operative diagnosis usually confirms the posterior lie.
It is my experience that with appropriate diagnosis and minimal intervention, this condition can be corrected by assisting the baby to rotate as soon as it is diagnosed. Many times the position is not diagnosed until labor is advanced and progress arrested. Even when it is diagnosed, care providers offer comfort measures only, believing that the posterior will eventually resolve, or can be corrected in second stage after progress is arrested. Labor and delivery nurses are often untrained in diagnosing posterior, and the woman usually doesn't see her physician until near the end of labor. Even if the physician was present and an early diagnosis made, generally he/she would do nothing to correct the position.
When progress in labor is slow, often the first action taken is to break the amniotic sac, followed by pitocin augmentation. This is the worst thing that can be done in a posterior labor since when the waters are broken and contractions are enhanced, the baby's head will descend, only worsening the situation. In order to become anterior, it is necessary for the head to go through a long rotation of up to 180 degrees. (Normal rotation requires a 90 degree turn or less). If the head descends too deeply before rotation is accomplished, the risk of a deep transverse arrest increases, greatly reducing the chances for successful vaginal delivery.
If the position is not adequately diagnosed until late in labor, the only recourse may be to offer a para-cervical block or an epidural anesthesia as it is almost impossible for the mother to relax enough to allow the deep muscles of the pelvic floor to relax sufficiently to allow the baby to turn. Nothing can prepare a mother for the severe unremitting pain that accompanies labor when the baby is in a posterior position. Often, labor begins with short, painful yet irregular contractions that are often shrugged off by care givers as "false labor." It may not be productive as the ill-fitting posterior head is not properly applied to the cervix, but the mother IS experiencing discomfort! She is often sent home to wait for "real labor" to begin but is unable to sleep and often unable to eat, sometimes for several days. So, adding to the stress of a painful back labor, we begin with a mother who is already tired out! I have heard women describe the pain as "it felt as though someone were sawing my back in half" or, "I couldn't even tell when I was having contractions because my back hurt so much!" All attempts to ease the pain have little effect and the labor is a long, hard exercise in determination. Many midwives attending out-of-hospital births have not been taught to help correct a posterior presentation, and despite their best efforts are forced to transport the woman to the hospital when confronted with a mother begging for pain relief or after several hours of pushing have resulted in little progress or a large caput has formed. Then there is the mother who finally delivers her baby after a 36 hour labor and is so exhausted by the ordeal that she has difficulty bonding with the baby, postpartum involution is delayed and she may suffer from urinary tract infections due to the pressure upon and swelling of the anterior vaginal wall. Did I fail to mention those nifty lacerations up top? I would love to see this picture changed. As a midwife, it is my goal to do everything that I can to help the mother to achieve an optimum birth outcome, to use my skills to alleviate unnecessary pain and suffering and to help a new family begin in safety, peace and joy.
Hence the purpose of this article. The incidence of a posterior presentation occurring at the onset of labor is 15 to 30 percent, and many such babies rotate spontaneously to an anterior position. When the pelvis is adequate, a posterior baby may be born face up with little or no difficulty, as if saying, "Surprise! It's my little face!" On once such occasion, as a woman was delivering precipitously here in our center, my daughter who was assisting at the mother's side, and "Mom, the baby's ear is upside down!" just before the rest of her head came out, with the baby looking straight up at her mother. There are, however, many Cesarean sections done for persistent posterior labors when failure to progress occurs, or when maternal exhaustion or a transverse arrest makes vaginal delivery either very traumatic or impossible. As we are unable to guess at onset of labor what the possible outcome will be, I feel it is imperative that every effort be made to avoid both a long and difficult labor and possible necessary operative intervention by very early diagnosis and correction of the position. We see our clients weekly during the last month of pregnancy. One of the things we are careful to assess is the baby's presentation and position. An ROA position is watched expectantly, as statistically ROA is much more likely to become posterior than an OA. If the baby is posterior, we give the mother exercises to try to help the baby turn. Having the mother do pelvic rocking three times daily in sets of twenty often assists the baby to assume a more favorable position. It may also be helpful to have the mother assume a knee-chest position for twenty minutes, three times a day, or to utilize a slant board as with a breech baby to help disengage the baby, allowing gravity to assist in the rotation. At the onset of labor, the position is re-evaluated and if the exercises have not helped to change the presentation, we encourage her to come into the birth center in early labor. It is relatively simple to assist the rotation of the baby when the mother is in early labor, and very difficult once labor becomes advanced.
There are some women who seem to be more at risk for a posterior position. The woman who has an android or an anthropoid pelvis, or a woman who has a narrow inlet is more prone to have this as well as other abnormal positions. Certainly, the woman who has had a previous posterior labor is much more likely to suffer a repeat. Remember to keep a watchful eye on an ROA.
Diagnosis of Position Prenatally:
- During the prenatal exam, the mother often exclaims that the baby has too many hands and feet, and the moving limbs may be easily felt and seen.
- The mother often complains of frequency of urination due to the baby's brow pressing against her bladder. Sometimes she will also be incontinent, not being able to feel an urgency to urinate as the baby's head presses out urine.
- The mother may exhibit signs of a urinary tract infection, with the above frequency of micturation, a feeling of constant pressure at the symphysis, (above the pubic bone), and an attendant lower backache. (In this case, it is always appropriate to test the urine for bacteria, as UTIs are more likely when the bladder is not completely emptied.)
- It may be difficult to auscultate fetal heart tones, or the tones may be indistinct. When it is suspected that the baby is posterior, have the mother roll to the side and the heart tones will be more easily heard.
- While the breech is easily palpated at the fundus, it may be difficult or impossible to feel the outline of the baby's back, and the head will appear to be engaged.
Assisting in Anterior Rotation Prenatally:
- Have the mother do the "pelvic rock" exercise at least three times daily.
- She may assume a knee-chest position for twenty minutes, three times a day.
- Have the mother lie on a slant board (as with a breech position) several times a day for thirty minutes at a time.
- Have the mother take warm baths and gently massage and encourage her baby to "roll over". We have found it very effective for the mother to visualize her baby in the correct position and to talk to her baby, telling it to move as well. One time we had a particularly stubborn baby, who liked the way he was lying just fine. The mother had suffered with a previous posterior labor and was very anxious that this not be a repeat performance. She had tried in vain to get this kid to cooperate, so I called the dad in and said, "Show this baby who's the boss!" Dad said, "Turn over, Baby!" and he did.
Diagnosis of Posterior of Labor:
- Early labor may be marked by a long period of irregular uterine contractions with little or no dilation. Contractions may be more frequent yet of shorter duration than desirable or expected in early labor, e.g.: every three minutes but lasting only three seconds. This is due to inadequate application of the presenting part.
- Palpation of the baby's position abdominally is not sufficient as it is possible that the deeply engaged head may remain posterior even though the baby's body appears to be aligned as in an ROA or LOA position.
- Auscultation of the fetal heart tones is not a reliable method of assessing fetal position as they may be heard through the baby's chest as well as through his back.
- The mother usually complains of a persistent backache, which even in early labor may be severe enough that the pain of contractions is secondary. As a backache may be present even in a normal anterior presentation, it is important that a vaginal examination be done to correctly assess the baby's position by the fontanels.
- In the ROP position, the sagittal suture line will be felt obliquely, (from one o'clock to 7 o'clock), and it will be possible to feel the bregma (larger front fontanel) at the top and to the side of the pubic bone (by 1 o'clock). It may be possible to feel the top of the baby's ear as well.
- Assuming that the mother's cervix is soft and a little dilated, a finger must be inserted through the cervical opening in order to accurately determine the direction of the suture lines and to find the anterior fontanel. If the head is in a posterior position, you will readily find it between 12 and 3 o'clock on the fetal skull. Courage! This exam may not be pleasant for either you or the mother, but when you consider that you may be saving her endless hours of an extremely painful labor, WITH A GUARANTEED OUTCOME, your task will be easier. If you are not able to find the anterior fontanel, the baby is probably in the correct position, as when the head is LOA or ROA, the posterior fontanel usually cannot be felt unless the head is assuming a military position, which is another story!
Assisting Anterior Rotation During Labor:
- When it is verified that the baby is in a posterior position, the first thing that I do is to have the mother assume and maintain a knee-chest position for approximately 45 minutes. Although this position is not the most comfortable one for the mother, it is very effective as it allows the baby more room in which to rotate. I find that the mother tolerates this position very well if she is not in advanced labor. We make sure that she is well supported by lots of pillows and give her lots of encouragement and emotional support. Often, while in the knee-chest position the contractions become more regular and more effective, which also assists the baby's rotation.
- If the mother cannot tolerate the knee-chest position for as long as necessary to turn the baby, we alternate by placing her in an exaggerated Simm's position (lying on left side, two pillows under right knee, which is jack-knifed, left leg straight out and toward the back).
- Every effort should be made to avoid rupturing the membranes, as the "pillow" offered by the forewaters gives a cushion on which the baby's head may spin more easily. Furthermore, if the waters break before the baby has rotated to the anterior, it is possible that sudden descent of the fetal skull will result in a deep transverse arrest!
- If labor is more advanced when the posterior is identified, say 4-5 centimeters, it may be helpful while the mother is in the knee-chest position for the attendant to place her hand in the mother's vagina and gently lift the head, somewhat disengaging the head and allowing it to turn to anterior.
- If the posterior has not be discovered until complete dilation, or if the above methods have not been applied in early labor, the baby's head may still be turned to make delivery more likely. Again, placing the mother in a knee-chest position, with knees slightly apart, the midwife may place her hand in the woman's vagina (remember, your hand is smaller than the baby's head!). Attempt to lift the head up by grasping the head firmly, waiting for a contraction and turning the baby into an anterior position. As soon as the head is correctly positioned, hold on tight and when the uterus contracts again, urge the mother to push very hard! If the amniotic sac has not previously ruptured, rupture it now! This will assure that the position remains fixed and the baby will usually be born very rapidly. This procedure is both safe and sane, yet it must be acknowledged that it will take some physical strength to turn this recalcitrant little head against the force of a good contraction.
I have addressed this article to the prevention of complications which may result when early diagnosis and correction has not been made of the posterior position, and to offer some suggestions for assisting anterior rotation. Placing the woman in a knee-chest position and lifting the head is also an effective aid in correcting military, brow and asynclitic positions. It is my hope that through early diagnosis and appropriate intervention, many women might be liberated not only from long and difficult labors but also from complications of such labors leading to inevitable cesarean sections. I have used these techniques with very favorable results for many years. To date, I have had to transfer only one woman (in 1977) for a transverse arrest due to my inexperience at that time in diagnosing her posterior baby. Even a woman birthing in the hospital could help herself if she is having excruciating back pain or if she is told her baby is posterior by assuming a knee-chest position until she feels relief from the back pain or for at least half an hour. For those of us assisting VBAC moms who have had a posterior labor leading to cesarean, or moms who previously have had vaginal deliveries after long posterior labors, a word of caution: In my experience, when a subsequent baby is not in a posterior position, the women are often advanced in labor before they realize that they ARE in labor. This has led to many interesting and amusing situations!
Addendum: The currently advised obstetrical management of posterior in arrested second stage. From a Detroit newspaper: An obstetrician here has developed a modified technique for manual rotation of the fetal head in cases of prolonged second-stage labor. In his experience with about 50 patients, he has found the technique less traumatic to mother and fetus than the use of forceps. "Prolonged second-stage labor is often caused by persistent occiput posterior or transverse arrest of the fetal head," notes the physician. "While the majority of these will undergo spontaneous rotation, some will not." The doctor's procedure is to rotate the head from either a posterior or lateral transverse position to the anterior position. The diameter that must enter the pelvis is thereby decreased by as much as a centimeter and the head descends more rapidly. "The idea is to bring the posterior fontanel forward from the 3, 6, or 9 o'clock position to the 12 o'clock position. Then the baby is more deliverable. In the right-sided position, you rotate it clockwise. In the left-sided position you should rotate it counterclockwise." The obstetrician stresses that the physician should put his fingernail on the lambdoidal suture. "The head is smooth and covered with vernix, so you jut can't turn it with your finger alone. You must be sure to anchor your fingernail in the crease between the bones. And do it during contraction; otherwise the head won't turn easily," the obstetrician explains. The modified manual rotation technique is not meant to be a replacement for forceps. But with it the doctor has had to use Kielland's forceps in only about 10% of the patients. "When left entirely to natural forces, resolution of prolonged second stage labor may require several hours, increasing maternal exhaustion, maternal and fetal morbidity, and possibility of fetal mortality," he observes. "Good obstetric practice recommends timely, judicious intervention. The technique I use is simple and can be used by midwives, medical students, and interns as well as residents." I again assert that to refrain from acting in the interest of the mother by not correcting a posterior in early labor when it is both non-interventive and safe, is to inflict needless pain and suffering upon the mother and her baby, and may lead to a much higher level of intervention, i.e.: drugs, episiotomy, forceps, cesarean section and not the least, digging one's finger into the baby's fontanel!
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