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Tuesday
Oct282008

Computers to Determine if a Woman Needs a C-Section Early in Labor?

The patent for an invention made with government support under a grant awarded from the National Science Foundation was published in June as a “SYSTEM AND METHOD FOR ANALYZING PROGRESS OF LABOR AND PRETERM LABOR

Authors of the patent’s application discuss the rising cesarean rate (especially primary and elective repeat c-sections) in the U.S. and cite dystocia as the most common indication for the surgery. The definition of dystocia used is:

 …a labor abnormality resulting in abnormal progression and may be due to problems with power (uterine contractions and/or maternal expulsive effort), passenger (position or size of the fetus), or passage (shape or size of the birth canal).

According to their research, many groups have tried with little success to predict which patients will experience labor dystocia. In addition, they note that augmenting with synthetic oxytocin is common in protracted or arrested labors, yet the definition of “minimally effective uterine activity” as the goal of augmentation is vague and inconsistent.

One of the intended applications of this invention is “early diagnosis and management of power problems,” or, problems with uterine contractions and/or maternal expulsive effort.

Authors report that the VBAC rate has fallen by nearly two-thirds since 1996 primarily due to safety concerns and cite the discrepancy between VBAC rates reported for 2003 (10.6%) and the target of 63% outlined in the government’s Healthy People 2010 Framework (http://www.healthypeople.gov/About/).

The Background of Invention section continues:

Women who labor and then fail to deliver vaginally have more complications (primarily infection and hemorrhage), incur more expense, and consume more resources (labor suite, nurse, etc.) than women who have an elective abdominal delivery. For VBAC patients, who are at increased risk for labor dystocia, the risk of uterine rupture increases the potential for a catastrophic outcome, and elective repeat cesareans are becoming the standard.

With declining numbers of patients attempting a subsequent vaginal birth after cesarean (VBAC), 60% of cesareans may relate directly or indirectly to the diagnosis of dystocia. The diagnosis of dystocia, however, is a matter of debate since, if given enough time, many very slow and even arrested labors will eventually proceed to vaginal delivery.

 

A brief summary so far…

The cesarean rate is too high. Dystocia may relate directly or indirectly to 60% of cesareans. There has been little success to date in predicting who will experience dystocia. Women with dystocia often have their labors augmented with oxytocin, the goal of which has been poorly and inconsistently defined. Laboring and then failing to deliver vaginally increases maternal morbidity, costs more and commands more hospital resources than elective cesarean sections. For VBAC patients, who “are at an increased risk for labor dystocia” and for whom there is a chance of catastrophic uterine rupture, elective cesareans are becoming the standard. Dystocia is a labor abnormality marked by abnormal progression and, again, related to 60% of cesareans but “if given enough time, many very slow and even arrested labors will eventually proceed to vaginal delivery.”

 

So the problem isn’t really dystocia, is it? It’s not allowing enough time for labor to take its course without artificially inducing and augmenting the process.

 

By citing the rising c-section rate and the huge discrepancy between the government’s Healthy People 2010 target for VBAC rates and the actual low VBAC rates reported for 2003, the assumption is that the invention will remedy what appears to be an out-of-control surgical birth epidemic. While this system for measuring uterine activity may serve as a valuable tool for research, it is unfair to women to hook them up to a machine to tell them early in labor whether their uterus will fail at birth. Technology concerned with “early diagnosis and management of power problems,” also defined as problems with uterine contractions and/or maternal expulsive effort is a guaranteed way to increase the cesarean rate and justify each case in court with an impressive mathematical breakdown of efficiency of contractions and dystocia prediction indicators.

 

In the section entitled “Brief Summary of the Invention” is a description of the use of multiple electrodes for assessing uterine electrical activity that will be affixed to the woman’s abdomen. The subject invention will utilize the readings to quantify whether the contractions are considered efficient.

“Contraction efficiency enables clinical assessment of various aspects of labor, including:

  • Progress of labor monitoring: the ability to track efficient versus inefficient contractions allows the clinician to know when a patient’s labor is unlikely to progress to delivery. This early detection of failure to progress can save the hospital money, save the staff time and effort, and avoid problems that might be caused by prolonged attempts to deliver vaginally. [See my comment 1 below excerpt]
  • Effectiveness of labor augmentation: the ability to identify the need for oxytocin, and to rapidly assess its effect and speed its accurate titration, with a minimum of cervical exams, thus reducing the risk of chorioamnionitis [See my comment 2 below excerpt]
  • Transition during labor induction: the ability to recognize when a misoprostil or other induction is ready for oxytocin, limiting cervical exams and speeding inductions by avoiding unnecessary delays.
  • Preterm labor monitoring: many patients arrive at the hospital with preterm labor symptoms. Today, there is not a clear method of determining whether the patient is actually in preterm labor or not. This invention may be used to rapidly triage patients and send home those patients who are not in preterm labor.
  • Home monitoring: either similar to the above discussion for continuous preterm labor monitoring at home, or for parents who would like a better indication of when they should leave for the hospital (e.g. to discriminate between real labor and false labor).
  • External IUP prediction: EHG cannot currently replicate the performance of internal monitoring of uterine pressure (IUPC). With an appropriate understanding of the electrical characteristics of the EHG, a non-invasive method of predicting IUP within a certain range is possible. Thus replacing the role of the IUPC in determining the adequacy of contractions.
  • Detection of elevated baseline uterine tone and uterine rupture. The subject invention can predict and detect problems with overall uterine activity. [See my comment 3 below excerpt]
  • Patient feedback on effective methods of ‘pushing’

 

 1. “Early detection of failure to progress.” Now women will know if they need a c-section before wasting expensive bed space, nursing care and pharmaceuticals in the hospital. The clinician administering the test with the subject invention will be helping the hospital create a paper trail akin to electronic fetal monitoring to justify use of early intervention.

2. The invention could help assess the need for induction and/or continued augmentation that may lead to a decrease in the number of cervical exams administered to verify progress. This could be helpful if the induction was medically indicated. Did labor need to be artificially initiated? Why? Who determined that it was progressing too slowly? By whose standards? The assessment of the “need for oxytocin” should begin with these questions.

3. If this invention can predict and detect problems with uterine activity, such as uterine tone and uterine rupture, then VBACs can be considered safer than ever, correct? Now uterine rupture can be detected externally while in labor?

 

The technology may be groundbreaking in measuring uterine electrical activity in a non-invasive manner, especially if it can actually predict uterine rupture. Its application as a means of predicting labor progress and labor outcome, however, toes an ethical line if used to stamp a patient with “FAIL” and roll her to the OR.

 

The creation of contraction efficiency and dystocia predictive indicators is based on a data set of 388 term patients, 61 of whom had c-sections. The following information was stored in a database and patient subsets from this database were considered suitable for initial design of the predictive models:

  • Maternal age
  • Height
  • Weight
  • Race
  • Any diagnoses
  • Obstetric history
  • Labor onset (spontaneous versus induced)
  • Membrane status (artificial versus spontaneous rupture, time)
  • Gestational age
  • Fetal presentation
  • Estimated fetal weight
  • All cervical examinations (including dilation, effacement and station)
  • All medications administered with dose and time
  • Continuous cardiotocographic and all data from the abdominally sited electrodes including individual impedances
  • Information regarding the type of delivery, newborn weight and Apgar scores

 

There are so many more relevant variables in labor and birth than those listed. Was there a supportive person with the woman during labor? What was her emotional state like during labor? Was she scared? Did she feel safe?

 

The headless (and oddly nipple-free) subject of the patent illustration is a perfect representation of failing to take the complex psychosocial and emotional components of childbirth into account in scientific research.

 

Another piece of technology used to label a woman’s body as faulty is the last thing today’s hospitals need.

 

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