Consortium for the Evidence-based practice of Obstetrics -- 
C.E.O. is dedicated to bringing science-based 
maternity care to all childbearing women

 Quotes and Excerpts from and 
 other respected sources  of professional information
on safety, complications & practice trends for obstetricians  

Bibliography, Recommended Reading and Scientific Citation from obstetrical sources for the:

Physiological Management of Normal Labor and Spontaneous Birth

Guide to Safe and Effective Care During Labor & Pregnancy and Birth; Maternity Center Association, 2000  

Upright Positions  Offer Most Room  for Delivery --MR pelvimetry study; February 1 2002 • Volume 37 • N0 3

Women’s Position During Second Stage of Labour, Cochrane Systemic Reviews, Journal Birth 28:1 March 2001;

Delayed Pushing Doesn't Increase Fetal Trauma -- Second-stage labor; February 1 2002 • Volume 37 • No 3  

Reconsideration of “Purple Pushing” Urged, ObGynNews; Mar 15 2003 Vol 38, No

Editorial ~ Home Delivery -- Why? Michael Fleming, MD, Assistant Professor, Department of Family Medicine,  School Medicine, University of North Carolina, Chapel Hill  

~ This editorial includes an excellent perspective by a family practice physician on why and how to employ physiological principles in hospital-based obstetrical practice, including the full-time presence of the primary caregiver during active labor

Upright Positions  Offer Most Room  for Delivery --MR pelvimetry study; 2002 • Volume 37 • N0 3

Upright birthing positions provide significantly more room for delivery in terms of pelvic dimensions, compared with lying supine, Dr. Thomas Keller said at the annual meeting of the Radiological Society of North America.

He and his colleagues at University Hospital, Zurich, Switzerland, performed MR pelvimetry on 35 nonpregnant women to compare pelvic bony dimensions in the supine, hand-to-knee, and squatting positions.

At the sagittal outlet, both the hand-to-knee and squatting positions provided significantly more room than the supine position (11.8 degrees, 1.3 cm; 11.7 degrees, 1.3 cm;

and 11.5 degrees, 1.3 cm, respectively).

Similarly, the hand-to-knee (11.6 degrees, 1.1 cm) and squatting (11.7 degrees, 1.0 cm) positions provided more room for delivery at the interspinous diameter compared with the supine position (11.0 degrees, 0.7 cm).

The intertuberous diameter was wider in the squatting position than the supine position (12.5 degrees, 0.8 cm vs. 12.4, 1.1 cm).

These differences are statistically significant and confirm the advantages of birthing positions long practiced in other cultures, the study's coauthor Dr. Rahel Kubik-Huch noted during an interview.

Although few women will be physically capable of switching through several positions while giving birth, the theoretical ideal would thus be to adopt the hand-to-knee position to help the presenting part through the interspinous diameter, and to squat rather than remain supine as the [head] traverses the sagittal outlet, said Dr. Kubik-Huch, also of University Hospital.

 There were no significant differences in pelvic dimensions between the 25 nulliparous and 10 parous women, who were
 matched for age, weight, and body mass index. 

Women’s Position During Second Stage of Labour, Selected Cochrane Systemic Reviews, Journal Birth 28:1 March 2001;

A substantive amendment to this systemic review was last made on 23 March 1999. Cochrane reviews are regularly checked and updated if necessary. 

Abstract /Background: For centuries there has been controversy around whether being upright (sitting, birth stools, chairs, squatting) or lying down had advantages for women delivering their babies. 

Main results: Use of any upright or lateral [side-lying] position, compared with supine [lying flat on the back], was associated with:

1. Reduced duration of second stage labor  
2. A small
reduction in assisted deliveries [use of forceps or vacuum extraction].  
3. A
reduction in episiotomies    
Reduced reporting of severe pain during second stage of labor  
Fewer abnormal fetal heart rate patterns.

Reviewer's Conclusions:  Woman should be encouraged to give birth in the position they find most comfortable. Until such time the benefits and risks of various delivery position are estimated with greater certainty when methodologically stringent trials data are available, then women should be allowed to make informed consent choices about the birth position in which they might wish to assume for delivery of their babies.  

Delayed Pushing Doesn't Increase Fetal Trauma -- Second-stage labor; February 1 2002 • Volume 37 • No 3

Delaying pushing [i.e., physiological or non-directed] until the mother experiences Ferguson's reflex can minimize her fatigue and does not increase the likelihood of fetal trauma during second-stage labor. We should try to take advantage of natural physiologic function as much as possible during birth,” said Ellen Kopel Zottoli, R.N., of Sarasota Memorial Hospital.

Many women experience a latent resting period near the time of complete dilation that is characterized by a decrease in uterine activity. This usually lasts about 20 minutes and is a time when the mother can rest and collect herself before beginning to actively bear down, Ms. Zottoli said at a symposium on high-risk pregnancy sponsored by Symposia Medicus.

Then, when the fetal head descends past the ischial spines (+1 station), the mother feels the sudden strong urge to bear down. This is Ferguson's reflex, and it typically is accompanied by a loud maternal groan.

If women are permitted to wait until they experience this response [Ferguson reflex] to the pressure of the fetal head stretching the musculature and stimulating the nerve receptors in the pelvic floor, they are less likely to be exhausted by the birth. This has important implications for subsequent bonding with the baby and breast-feeding.

Delaying pushing also has little effect on duration of labor. In a study of patients who had an epidural during delivery, one group of patients was instructed to start pushing the minute they reached 10 cm of cervical dilation, she said. Patients in the other group were asked to not push for 1 hour unless they felt the urge to do so. "The patients who were not asked to push only delivered 8 minutes later than the others.

“If I were a mom trying to push my baby out, I'd be pretty glad I didn't push for those 52 minutes,” she said.

There's also no need for women to routinely try pushing for a count to 10. When allowed to push on their own, they tend to push about three to five times each contraction, and they tend to push for about 4-6 seconds, Ms. Zottoli said. “If we let [the mother] go with her instinct, she's going to do a much better job of coordinating her intra-abdominal and intra-thoracic pressures to make a more forceful push.”

Open-glottis pushing, rather than bearing down while holding the breath, also should be encouraged. When the mother bears down while holding her breath, she's increasing her intra-thoracic pressure and decreasing her cardiac output and blood pressure. This results in a diminished blood flow to the fetus and an increased risk of hypoxia, Ms. Zottoli said.

Moreover, the so-called 2-hour rule needn't be followed in all cases. This obstetrical practice, which is of unknown origin and dates to the early 1900s, is arbitrary, and if the fetus and mother are in good shape at the second stage, it's not necessary to intervene surgically at 2 hours.

A retrospective review that included 733 women with full-term, vertex fetuses who were delivered by unplanned cesarean birth cited “lack of progress” as the reason in 68% of cases. In 45% of nulliparous women and 34% of those who were multiparous, prolonged second-stage labor did not occur according to American College of Obstetricians and Gynecologists criteria (Obstet. Gynecol. 95[4]:589-95, 2000).

Reconsideration of “Purple Pushing” Urged, ObGynNews; Mar 15 2003 Vol 38, No 6

Physiology suggest that standard positioning and pushing techniques used during labor and delivery require rethinking, according to Lisa Miller, certified nurse-midwife.   

Long Valsalva's maneuvers -- or "purple pushing"--- and standard supine [i.e. lying on one's back] positioning should be reconsidered

Purple pushing--or closed-glottis pushing--during which the patient holds her breath for 10 seconds while pushing is safe in the approximately 80% of low-risk pregnancies. But that doesn't mean it works best. Furthermore, in physiologically high-risk cases, the baby can't tolerate that kind of pushing, said the former labor and delivery nurse-turned-midwife, who is also a lawyer. 

....near-infrared spectroscopy used to evaluate fetal effects revealed that closed glottis and coached pushing efforts [when the  doctor or nurse instructs the mother to hold her breath & push as long and hard as she can] led to decreased mean cerebral 02 saturation and increased mean cerebral blood volume. All Apgar scores were below 7 at one minute and below nine at five minutes. 

Open-glottis pushing, on the other hand, allows the patient to exhale while bearing down and leads to minimal increase in maternal blood pressure and intrathoracic pressure, maintained blood flow, and decreased fetal hypoxia. Long Valsalva pushing can adversely affect maternal hemodynamics, which in turn adversely affects fetal oxygenation, said Ms Miller, who also is president of Perinatal Risk Management and Education Services in Chicago. 

Furthermore, several studies have suggested that in patients who have received epidural anesthesia, delayed pushing is safe and effective for reducing delivery difficulty and decreasing variable decelerations in the fetus

Pushing in general should be limited to 6-7 seconds, and should be a spontaneous response to a strong urge to push. 

Coaching of the patient should be limited to encouragement of open-glottis pushing with slight exhalation during pushing and [directed coaching] should only be offered on an as-needed basis. As for maternal positioning, her mantra is : "I am here to serve my patient -- no the other way around,"....

A squatting position will provide the most intrauterine pressure and is safe in low-risk patients. Higher-risk patients, such as those with fetal heart rate changes, should avoid this position; in those cases, a side-lying position will improve heart rate patterns and Apgar scores. 

Other positions to consider include semi-recumbency, standing or leaning and hands and knees positioning. Some patient may prefer use of a birth chair or stool...

Remember the goals of positioning when helping a patient determine the best position. These include 

facilitation of alignment of the presenting part to the pelvic axis, 
encouragement of the mother's efforts
toward giving birth, 
allowing for larger pelvic diameters
improving maternal comfort  
promoting fetal well being.... 

REMEMBER THE FRIEDMAN CURVE  -- when a patient reaches 8 cm of dilatation, remember the deceleration phase of the Friedman curve and avoid starting Pitocin as a reaction to this phase. At this phase of labor, the patient's body "takes a break" [called the "rest and be thankful phase by Shielia Kitzenger] in preparation for the hard work about to come... But this is often misinterpreted as stalled labor....

Giving Pitocin at this stage can create fetal hyper-stimulation and can be considered "Muchausen OB," because it is basically creating an emergency in order to respond to it....  "This is indefensible", she said.