ACDM
California College of Midwives
Sept 1999 Principles of Mother-Friendly Childbearing Services General Guidelines for Expulsive Labor
-- the "Perineal phase", the Fetal Ejection Reflex Defined and techniques that protect the mother's perineium while making the routine use episiotomy unnecessaryDiscussion & Background about Routine Episiotomy
Background: Certain predictable problems are created when there is no distinction between the 2nd and the perineal stage of labor. The biological, physiological and psychological aspects of second stage change quite dramatically, depending on where the baby is in relation to the pelvic inlet, mid-plane or outlet. The role of gravity in relations to maternal posture and the mother’s reaction to perineal sensations and psychological response to the impending birth changes as the baby’s head progresses down through the stations of fetal descent. Obstetrical textbooks usually do not distinguish between the first phase of maternal pushing (moving fetal head through cervix and down to a +3, +4 station) and the last half which includes rocking the baby under the pubic arch, distending the perineum, extraverting the anus and eventually the crowning of the baby’s head. However, midwives have historically made this distinction in the course of managing the expulsive stage.
It is importance to avoid all maternal postures that result in the childbearing mother bearing her body weight on her sacrum -- this closes the bony aperture of the pelvis by 20-35% and increase soft tissue resistance resulting in "mattress" dystocia.
Conservation of Maternal Effort through right use of Gravity -- During the second stage (all stations above +3 or 4) the best progress and the least maternal effort is achieved when the mother is in a vertical posture. The most favorable accommodation of the irregularly shaped fetal head to the irregularly shaped maternal pelvis is achieved via a combination of maternal mobility (changes of position) and the pelvic enlarging effects of a squatting position, in which abduction of the thighs to the side and slightly back against the abdomen increases the intra-abdominal pressure while increasing the pelvic diameter.
The space-making role of abducted legs may be easily verified by anyone at any time by sitting down on a chair and placing the fingers of each hand under the protuberances of the ischium by sliding them in from the sides (by each hip bone) while the knees are still touching. Then splaying your legs to each side into a wide open position with knees far apart. You will feel the outward movement of these bones splaying open in an arc beneath your fingers approximately 2-3 cms. The dynamic effects of gravity on the human pelvis have been overlooked for centuries as the teaching of anatomical principles was based on the use of skeletons in which the normally elastic cartilage had turned to cement after death, thus rendering this biologically activity invisible in the cadaver pelvis used for determining anatomical relationship.
Psycho-social/sexual aspects of expulsive labor -- creates maternal needs for privacy and a feeling of security which shares many of the same characteristics as the social norm for using the bathroom. These are brought into play by the strong expulsive sensation of 2nd stage in which many childbearing women are, quite naturally enough, convinced that they needs to have a bowel movement. Fear of soiling often means that the mother is triggered to use the muscle of her buttocks to hold back in the rectal area while simultaneously using her abdominal muscle in an attempt to push the baby down through the birth canal. This creates a push-pull war of sorts that works against the goal of expulsive labor.
Facilitating the mother to push fully while simultaneously relaxing the gluteal muscles of the buttocks is best addressed by suggesting she sit on the toilet for a minimum of 3-6 pushes when she first begins to feel "pushy". Sitting produces a body posture sharing many of the same characteristics of squatting. Supplying the mother with 3 or 4 inch prop under each foot helps her maintain good flexion and abduction of the thighs. This comfort measure also reduces the pressure on the under side of her thighs which if prolonged will interfere with circulation and contribute to vulvular edema.
Providing the mother with privacy in the bathroom except for the presence of her spouse or intimate family member and/or the midwife/L&D nurse addresses the intimacy needs of the situation. If there is justifiable concern about precipitous birth (a multip), the caregiver can monitor progress by placing a small mirror between the mother’s legs. By shining a flash light at the mirror while angling the mirror appropriately the perineum can be visualized to be certain that she does not inadvertently deliver while on the toilet.
The creative use of gravity to shorten the 2nd stage reduces the stress on the baby and associated risk of fetal distress. In addition, physiological postures and acknowledgements of the psyco-social/sexual aspects of the mother’s experience also reduce the number of times she must push and the actual quantify of body energy the mother must expend. When a mother pushes while lying in bed on her back she is bearing body weight on the maternal sacrum. This means she must overcome the deleterious forces of gravity which now work against her as the birth canal is a relaxed right angle aiming up towards the ceiling in this position. This closes the pelvic aperture down by 1/5 to one 1/3 (equal to 1 to 3 cms). The aggregate of these forces means at the very least 1/2 hour, often an hour or more of extra pushing and increased time with expenditure of incalculable amounts of finite maternal energy for very little gain.
The pushing stage comes at the end of labor, when the mother had lost sleep and not eaten for many hours, suffers from fatigue and often is discouraged. It is unkind to ask her to do the hardest physical work ever required by our normal biology (especially if it is a first vaginal birth) under these sub-optimal conditions. The normal amount of psi (pounds pressure per square inch) required to give birth to a first baby is approximately 120 psi. The uterus on its own produces only about 80 psi, which means that either the mother must use abdominal muscles and gravity to provide the missing 40 psi or the caregiver must pull with forceps / vacuum device at that level of downward torque. When every drop of maternal energy is expended on pushing to baby down to the perineum, there is nothing left for her to use for the perineal stage -- that is to push the baby’s head and shoulders out and across the perineum. This sets up the situation for the otherwise unnecessary surgical intervention of episoiotomy and its risks of bleeding, infection, prolonged postpartum pain, the need for narcotic medications and the disruption of bonding and breastfeeding that pain and drug use entails.
On those occasion when mothers are unable to be upright or out of bed due to a medical condition, side-lying is the physiologically appropriate position as the curve of Carus is neutral to gravity with the mother on her side. While not as effective as upright positions, at the very least side-lying does not require the mother to work uphill against the forces of gravity.
Management of Perineal Stage: The concept of a "perineal stage" is a functional definition of the latter part of 2nd stage used by many midwives to describe the biological and psychological events from a +four station to the actual crowning of the baby’s head and delivery of shoulders. It is during this period of time that a biological event occurs that French obstetrician Michael O’Dont describes as the "fetal ejection reflex".
The idea of fetal ejection is that at a certain time after the cervix is fully dilated the mother experiences a dramatic event in which the body simultaneous opens up (relaxes normal muscle resistance) while forcefully propelling her fetus downward. The fetal ejection reflex efficiently overcomes the usual soft tissue resistance and takes advantage of momentum to press the baby down and out. While the example of gastric emptying (emesis) makes for an unpleasant analogy, in truth it shares the same biological chain of events, except going in the other direction. This reflex usually is triggered when the baby’s presenting part is quite low and the pressure of the advancing head triggers the same expulsive receptors as used to move the bowels. To the observer it reminds one of the reflex commonly referred to as the "dry heaves" in which a sudden powerful contraction of the abdominal muscles causes a dramatic bodily event to occur -- often to the surprise of the mother herself.
In some multips the fetal ejection reflex is initiated long before the baby’s head presses on the perineum (perhaps as soon as the cervix is fully dilated) and the baby almost "free falls" through the birth canal and across the perineium in the matter of 1 - 3 pushes. However for most mothers there is more to this reflex that just the physical trigger of cervical dilation and pelvic floor pressure. Of equally or even greater importance is the psychological component. While it is impossible to predict which mothers will and who won’t experience this "labor-saving" biological event, many birth attendants have observed that a confident mother is more likely to do so than a fearful, anxious one who feels unsure of herself. While no caregiver can program mothers under her care to experience this beneficial reflex, acknowledgement of the pyscho-social/sexual nature of childbirth greatly helps.
There are a number of favorable positions for the perineal stage. Helping the first-time mother to remain upright until the perineal cleft (that part of the mother’s perineal anatomy including the anus that normally is tightly tucked up inside of the cleft of her buttocks) has flattened out and the 2-4 cms of caput is visiable at the vaginal introits is very useful. Squatting is an excellent choice to bring this about or a birth stool may be used. However it is better for the birth stool to be removed before the baby crowns and the mother to squat or to lie on her side. According to both historical (Dr. Joseph DeLee) and contemporary sources (nurse and direct-entry midwives) who have experience with a large number of spontaneous labors and physiological births, side-lying reduces the rate of perineal trauma and shoulder dystocia. It permits better control of the emerging fetus and the weight of the upper leg can be assumed to bow the pelvis (increasing the A-P diameter), which along with the elimination of "mattress dystocia" may account for the observed reduction in shoulder dsytocia and serious perineal trauma.
This may be particularly important in a vaginal birth after cesarean as it reduces the amount of force the mother and her uterus must expend to get the baby out. If the pelvis is reduced by 30% and the perineium pressed into the bed, the mother must muscle the baby past these impediments. In the process of overcoming this abnormal resistance, the pressure on the incised uterui is increase which could contribute to uterine rupture.
In a side-lying position, the mother’s upper leg can be held up by a family member or helper or it can be placed on a large pillow. In this position the caregiver sits on the bed next to the mother and in full contact with the small of the mother’s back and hips. If sitting to the right of the mother, the top (left) hand of the caregiver reaches across and to the side of the mother’s abdomen and down between her legs to the top of the baby’s crowning head, to maintain its flexion with the fingers. The lower (right) hand is placed palm down on the perineum to lightly support it during the birth of the head and more firmly supporting it during the delivery of the shoulders. A good many times the head is born without causing a perineal laceration, while the shoulders and arms delivers a karate-chop to the perineum. The DeLee side-lying method is superb for managing the delivery of the shoulders, compound arms and the remainder of the body.
It is imperative that the truth about the historical and contemporary use of episiotomy become widely known. Episiotomy is a painful, detrimental and potentially fatal surgical procedure unnecessary to normal childbirth but none the less done routinely by the obstetrical community despite its lack of scientific basis. The only medical justification for episiotomy is to rescue a baby suffering from fetal distress during the last 5 or 10 minutes of the birth process or in response to maternal exhaustion (and then only at the mother's request and with her permission).
The unnecessary and unwise use of episiotomy by the medical profession to be an ethical violation (if not a crime!) against childbearing women and believe that women have the right to know what doctors already know (but do not put into practice).
In addition to the damage done by the routine use of episiotomy (extensively documented by Dr. Woolley's treatise), its historical acceptance by the medial profession as the basis of their "normal" management of the perineal phase of childbirth means that obstetricians have never been taught (nor learned on their own) the historically successful midwifery principles and management techniques which are far more appropriate and useful. These well known (by midwives), easily learn and easily used methods protect the mother's perineium from unnecessary trauma and accidental laceration by the birth of the baby's head or shoulders. These protective principles requires that upright and mobile positions be used for second stage (right use of gravity) and that doctors do not place mothers in a position for delivery which includes weight bearing on the maternal sacrum (as this closes down the bony pelvis by approximately one third while requiring the baby to be pushed uphill against gravity at a 60 degree angle, causing fetal distress, maternal exhaustion and perineal lacerations, edema, pain and unability to urinate immediately after the birth and /or difficulty or pain in resuming normal intercourse postpartum). Appropriate protective methods also require a through understanding of how to facilitate the normal physiology of birth to the benefit of the mother's
I perineal tissue, which includes such techniques as right use of gravity, patience with nature, delivery in a side-lying position, maintaining flexion of the fetal head and supporting the perineium during the birth of the baby's head and again during the birth of the shoulders.
Because obstetricians do not utilize "good technique" in managing the "perineal stage" of the birth (the combined problems of inappropriate rate of episiotomy and failure to make right use of gravity there is a marked increase in pelvic floor disorders for older women (incontinence, uterine prolapse, etc). The president of ACOG is now using these "collateral damage" of childbirth as a rationale for medically unnecessary "elective" cesarean becoming the delivery method of choice. This is a life and limb threatening situation that must be rectified sooner rather than later.
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