Posterior Labor: A Pain in the Back
by Valerie El Halta
© 2005 Midwifery Today, Inc. All rights reserved.
I have become increasingly frustrated and angry that posterior position and its ensuing complications in labor and delivery account for an inordinate number of caesareans. Many of the women who come to us desiring VBACs have suffered a previous cesarean for "failure to progress" and "cephalopelvic disproportion" (CPD). Yet when we preview the women's records, the post-operative diagnosis usually confirms a posterior position (back of the baby's head toward the mother's back).
My experience is that with appropriate diagnosis, this condition can be corrected with minimal intervention by assisting the baby to rotate. But many times, the position is not diagnosed until labor is advanced and progress has stopped. Labor and delivery nurses are often untrained in diagnosing posterior positions, and the woman may not see her physician until she nears the end of labor. Even if the physician were present to make an early diagnosis, generally he/she would do nothing to correct the position. Instead, comfort measures would be offered until the situation eventually resolved itself, or was corrected in second stage after labor had arrested.
When labor progresses slowly, the first action often taken is breaking the amniotic sac, followed by Pitocin augmentation. This is the worst thing that can be done in a posterior labor since contractions are intensified. The baby's head descends quickly, which worsens the situation. In order to become anterior, the head must 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, and chances for successful vaginal delivery are greatly diminished. If the position is not adequately diagnosed until late in labor, the only recourse may be to offer a paracervical block or an epidural anesthesia as it is almost impossible for the mother to calm down 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, unrelenting pain that accompanies a posterior labor. Often labor begins with short, painful yet irregular contractions, which are often shrugged off by caregivers as "false labor." Even though the labor may not be "productive," since the ill-fitting posterior head is not properly applied to the cervix, the mother is experiencing discomfort. She may be sent home to wait for "real labor" to begin. Meanwhile, she is unable to sleep and may be unable to eat, sometimes for several days. So, adding to the stress of a painful back labor, we have 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 position. So despite their best efforts, they may be forced to transport the woman when she begs for pain relief or when several hours of pushing have resulted in little progress or formation of a large caput.
Another scenario is the mother who finally delivers her baby after a 36-hour labor, but is so exhausted by the ordeal she has difficulty bonding with the baby. Postpartum involution is delayed and she may suffer from a urinary tract infection due to pressure upon, and swelling of, the anterior vaginal wall.
As a midwife, my goal is to do everything I can to help the mother achieve an optimum birth outcome. To this end, I use my skills to alleviate unnecessary pain and suffering so a new family can begin in safety, peace and joy.
Early Diagnosis Is the Key
The incidence of a posterior position occurring at the onset of labor is 15–30 percent; many of these 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!" This happened once as a woman delivered precipitously in our center.
"Mom, the baby's ear is upside down!" said my daughter, who was assisting, just before the rest of the head came out, with the baby looking straight up at her mother.
Because we are unable to guess at the onset of labor what the outcome will be, every effort must be made to avoid both a long and difficult labor, and possible necessary operative intervention, by early diagnosis and correction of the position.
We see our clients weekly during the last month of pregnancy. We are careful to assess the baby's presentation and position. An ROA position (right occiput anterior) is watched expectantly, as this position is statistically more likely to become posterior than LOA (left occiput anterior). If the baby is posterior, we give the mother exercises to try to help the baby turn.
At the onset of labor, we re-evaluate the baby's position. If the exercises have not helped to change the presentation, we encourage the woman to come into the birth center in early labor. Assisting the baby's rotation early on is relatively simple, but once labor becomes advanced it is very difficult.
Some women seem to be more at risk for a baby that settles into a posterior, or other abnormal, presentation. Those with an android or anthropoid pelvis, or a narrow inlet, are more prone to these positions. Certainly, the woman who has had a previous posterior labor is much more likely to suffer a repeat.
Prenatal Diagnosis of Position
- 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 as the baby's head presses out urine.
- The mother may exhibit signs of a urinary tract infection (UTI) with the above frequency of micturition, a feeling of constant pressure at the symphysis (above the pubic bone) and an attendant lower backache. (In this case, testing the urine for bacteria is always appropriate, as UTIs are more likely when the bladder is not completely emptied.)
- Auscultating fetal heart tones may be difficult, or the tones may be indistinct. If you suspect the baby is in a posterior position, have the mother roll to the side and the heart tones will be more easily heard.
- While the baby in breech position is easily palpated at the fundus, feeling the outline of the posterior baby's back may be difficult or impossible and the head will appear to be engaged.
Assisting with Anterior Rotation Prenatally
- Have the mother do the "pelvic rock" exercise at least three times daily in sets of 20.
- Suggest that she assume a knee-chest position for 20 minutes, three times a day.
- Have the mother lie on a slant board (as with breech position) several times a day for 30 minutes at a time.
- Have the mother take warm baths and gently massage and encourage her baby to "roll over." We have found that having mother visualize her baby in the correct position and talk to her baby, telling it to move is often effective. Once, 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 about repeating it. She had tried in vain to get the baby 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 in 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 desired or expected in early labor. For example, they may occur every three minutes but last only 30 seconds. This is due to inadequate application of the presenting part.
- Abdominal palpation of the baby's position is not sufficient as the deeply engaged head may possibly remain posterior even though the baby's body appears to be aligned in a right occiput anterior (ROA) or left occiput anterior (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 to cause the pain of contractions to become secondary. Since a backache may be present even in a normal anterior position, a vaginal examination must be done to correctly assess the baby's position by the fontanels.
- In the ROP position (right occiput posterior), the sagittal suture line will be felt obliquely, (from one o'clock to seven o'clock), and feeling the bregma (larger front fontanel) at the top and to the side of the pubic bone (by one o'clock) will be impossible. You may be able to feel the top of the baby's ear as well.
- Assuming that the mother's cervix is soft and a little dilated, insert a finger 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 o'clock and three o'clock on the fetal skull. Have courage! This exam may not be pleasant for either you or the mother. Your task will be easier if you keep in mind that you may be saving her endless hours of an extremely painful labor, with no guaranteed outcome. If you are not able to find the anterior fontanel, the baby is probably in the correct position; when the head is LOA or ROA, the posterior fontanel usually cannot be felt unless the head is assuming a military position. (That, of course, is another story....)
Assisting Anterior Rotation during Labor
- When the baby has been determined to be in a posterior position, the first thing I do is 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 the baby has more room in which to rotate. I find the mother tolerates this position 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, contractions become more regular and more effective while in the knee-chest position, 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).
- Make every effort 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, sudden descent of the fetal skull may possibly result in a deep transverse arrest.
- If labor is more advanced when the posterior is identified, say 4 to 5 centimeters, the attendant may help by placing her hand in the mother's vagina, gently lifting and somewhat disengaging the head thus allowing it to turn to anterior, while the mother is in the knee-chest position.
- If the posterior has not been discovered until complete dilation, or if the other methods have not been applied in early labor, the baby's head can still be turned to make delivery more likely. With the mother in a knee-chest position, knees slightly apart, the midwife inserts her hand into the woman's vagina. She should attempt to lift the head by grasping it firmly, waiting for a contraction, then turning the baby into an anterior position. As soon as the head is correctly positioned, hold on tightly. When the uterus contracts again, urge the mother to push very hard. If the amniotic sac has not yet ruptured, rupture it now. This will assure that the position remains fixed and the baby usually will be born very rapidly. While this procedure is both safe and sane, it will take some physical strength to turn this recalcitrant little head against the force of a good contraction.
I hope that through early diagnosis and appropriate intervention, many women can be liberated not only from long and difficult labors, but also from the complications of such labors that can lead to caesareans. I have used these techniques for many years, and have had very favorable results. To date, I have transferred only one woman for a transverse arrest (and that was in 1977), due to my inexperience with diagnosing her posterior baby.
A word of caution: Women who have had caesareans due to posterior labors, or who have had vaginal delivery after long posterior labors, often are in advanced labor before they realize they are in labor with a subsequent baby that is not in a posterior position. This has led to many interesting and amusing situations!
Valerie El Halta, midwife, is retiring after 28 years and close to 3,000 babies. She offers gratitude and appreciation to all who have supported her through these years as friends, clients, teachers and students.
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