The paradox of electronic fetal monitoring: more data may not enable us to predict or prevent infant neurologic morbidity.

Electronic fetal heart rate monitoring has been used to identify periods of fetal risk, with the hope that clinical intervention would avoid the potential for perinatal death or neurologic damage. A literature review of 10 infant studies failed to document fetal heart rate patterns associated with neurologic injury or protocols for intervention to avoid neurologic injury. A separate analysis of fetal heart rate patterns from 55 brain-damaged infants failed to find consistent patterns that foreshadowed the observed brain injury. These findings should not be surprising, because the majority of infant brain damage occurs outside the intrapartum period and because electronic monitoring may identify times of fetal risk but was never expected to identify brain damage.

Abnormal labor and infant brain damage.

OBJECTIVE: To determine whether arrest disorders result in increased neurologic abnormalities in infancy or childhood. METHODS: Four hundred thirteen infants with arrest disorders as defined by Friedman criteria were matched to a similar population without arrest disorders. The median length of follow-up was 6 years for the study infants and 5.07 years for the controls. The numbers of children with abnormalities in the groups with and without arrest disorders, as well as the specific abnormalities encountered, were stratified by method of delivery. RESULTS: Thirty neurologic abnormalities were found in the arrest group and 37 in the control group; thus, the null hypotheses could not be rejected. In addition, although the control group was not followed as long as the study population, the diagnosis of abnormalities was more frequent in the later years in the controls. This suggests that had the follow-ups been equal, there would have been stronger proof that arrest by itself was not associated with infant brain damage. CONCLUSION: Our study confirms that labor diagnoses of prolonged active phase, protractions or arrests, and failure to descend are not associated with increased neurologic abnormalities. Delivery by cesarean or vaginal birth and use of oxytocin are not factors in the etiology of major brain damage.

Obstetric care and cesarean birth rates: a program to monitor quality of care.

OBJECTIVE: To study the quality of obstetric care in relation to rising cesarean rates, a Task Force was formed in New York state by the Department of Health and ACOG District II. The Task Force also included the Organization of Obstetric, Gynecologic, and Neonatal Nurses and the Hospital Association of New York State. The goals were to enhance hospitals' in-house review processes, standardize terminology, and improve the quality of care. A premise of the program was that if quality of care improved, cesarean rates would fall. METHODS: A Dictionary of Terms was developed to standardize clinical and diagnostic terminology. A two-tiered review process was instituted, using internal and external hospital reviews. A format for in-house review of obstetric care was developed and recommended to hospitals. External reviews were conducted at 24 hospitals during 1989-1990. Review teams, composed of obstetrician-gynecologists and obstetric nurses in active obstetric practice, assessed obstetric facilities, staffing, medical care, and the in-house review process. Contacts continued with the hospitals after site visits to follow up on implementation of recommendations. General recommendations to improve care, based on the overall program experience, were distributed to hospitals and physicians as part of educational efforts to improve quality of care. RESULTS: The state cesarean rate reversed. Statistics for 1989 and 1990 showed a stronger downward trend in reviewed hospitals than in non-reviewed hospitals. A survey of reviewed hospitals reported a positive response to the review process. CONCLUSION: A successful quality assurance program can be jointly developed by a state regulatory agency and a medical specialty society.

The incidence of cerebral palsy.

The clinician is often held responsible for obstetric events that are suspected of being related to cerebral palsy. To review the incidence of cerebral palsy and to aid the clinician in this situation, a search of published studies was conducted. Composite rates of cerebral palsy in different birth weight infants and cerebral palsy with and without serious mental retardation were calculated. The cumulative incidence rate at the age of 5 to 7 years was 2.7 cases of cerebral palsy for 1000 birth cohorts. Approximately 36% of all cerebral palsy occurred in the infant less than 2500 gm. Serious mental retardation (intelligence quotient less than 50) accompanied cerebral palsy approximately 30% of the time for the term infant and 18% of the time when the infant was less than 2500 gm. On the basis of a past estimation that 70% of cerebral palsy is of antepartum or unknown origin, the term infant at risk for intrapartum-attributed cerebral palsy may be about 1 in 2000 term births.

Caring for our future: a report by the expert panel on the content of prenatal care.

The report of the Expert Panel on Prenatal Care entitled Caring for Our Future: The Content of Prenatal Care was presented to the Assistant Secretary for Health, James Mason, MD, on October 2, 1989. The Panel noted the need for attention not only to the mother and fetus, but also to the infant and family. Besides traditional medical care concerns, the importance of psychosocial and environmental patient and family needs was emphasized. The Panel felt that the addition of the pre-conception visit to routine prenatal care made care more effective. Suggestions as to visit timing and content were made. The Panel noted the need for further understanding of many of the activities performed routinely in prenatal care.

Vaginal birth after cesarean: a meta-analysis of morbidity and mortality.

The cesarean birth rate has continued to climb despite efforts to counteract it. A major reason for this rise is the practice of elective repeat cesarean. We conducted a meta-analysis that included 31 studies with a total of 11,417 trials of labor to evaluate the association between birth route after a cesarean and morbidity and mortality for the mother and infant. Summary odds ratios were calculated. Maternal febrile morbidity was significantly lower after a trial of labor than after an elective repeat cesarean. The intended birth route made no difference in the rates of uterine dehiscence or rupture. The use of oxytocin, presence of a recurrent indication for the previous cesarean, and presence of an unknown uterine scar were also unassociated with dehiscence or rupture. After excluding antepartum deaths, fetuses weighing less than 750 g, and congenital anomalies incompatible with life, we found no difference in perinatal death rates. The proportion of 5-minute Apgar scores of 6 or lower was higher after a trial of labor, but we were unable to exclude very low birth weight fetuses or those with congenital anomalies from this analysis. Our findings argue for trials of labor for more women after a cesarean birth.

Vaginal birth after cesarean: a meta-analysis of indicators for success.

The cesarean birth rate has continued to climb despite efforts to counteract this trend. A major reason for this rise is the practice of doing an elective repeat cesarean. Our study used a statistical model of meta-analysis to analyze the findings of 29 individual studies that looked at the association between the success of a trial of labor and various preexisting conditions. We hypothesized that various preexisting factors, including cephalopelvic disproportion, previous breech, previous vaginal delivery, more than one previous cesarean, use of oxytocin, and the length of labor and extent of dilatation in the previous cesarean, would affect the prediction of the outcome of a trial of labor. After determining odds ratios for the individual preexisting factors from the individual studies, we calculated overall odds ratios which incorporated the findings from all of the studies. For previous cephalopelvic disproportion, the odds were 0.5 for a successful trial of labor; for prior breech, 2.1; for women with a previous vaginal delivery, 2.1; for women who had had more than one cesarean, 0.7; and for women receiving oxytocin, 0.3. We were unable to analyze other preexisting factors because the data were not available, but short discussions of some of these other factors are offered. Even though the success rates do vary with the different preexisting factors, the clinician may anticipate a greater than 50% chance for success in any individual labor.

Dating the early pregnancy by sequential appearance of embryonic structures.

A total of 97 transvaginal scans were performed from 4 to 12 weeks' gestation in normal and accurately dated gestations. The sequential appearance of six structures were examined: (1) the gestational sac only was present during week 4; (2) the yolk sac appeared in week 5; (3) the fetal pole with detectable heart motion was first seen in week 6; (4) the single unpartitioned ventricle in the brain marked week 7; (5) the falx cerebri appeared during week 9; and (6) the appearance and the disappearance of the physiologic midgut herniation were seen in week 8 and week 11, respectively. Inasmuch as the time in gestation at which these structures appear characterizes the gestational age more than any measurement at this age, we propose a practical method to determine the correct gestational age in early first-trimester pregnancy.

Arrest disorders and infant brain damage.

In the past, difficult labors have been associated with maternal and infant damage. Today, changing patient management is associated with less trauma and more frequent use of cesarean births to avoid potential fetal neurologic damage. In this report, arrests of dilatation and descent and prolongation of the decelerative phase of labor were reviewed with respect to the later appearance of brain damage in infants after 2 years of age, in association with obstetric interventions including cesarean birth, forceps, and oxytocin. Charts of 413 infants born after abnormal labors were studied. Log-linear analysis was performed to determine the contribution of method of delivery and oxytocin use to the presence of neurologic abnormalities. Statistical testing ruled out the presence in the model of a three-way interaction, and excluded the two-way interactions of neurologic abnormalities-oxytocin use and neurologic abnormalities-method of delivery. Chi-square tests of partial association and marginal association for the delivery-oxytocin interaction yielded values of 33.54 (P less than .0001) and 33.78 (P less than .00001). This model asserted that method of delivery and use of oxytocin were unrelated to the presence of neurologic abnormalities, but were related to each other.

A close look at early embryonic development with the high-frequency transvaginal transducer.

Transabdominal sonography has been, for the past two decades, used as an effective diagnostic and research tool in obstetrics. It is predominantly used in the second and third trimesters of gestation. Its use in the first trimester is relatively limited and mostly diagnostic in nature. The introduction of the higher frequency transvaginal transducer probe, with its higher resolution of the images, opens new possibilities to study early gestation. We studied embryonic development in 38 well-dated and normal pregnancies. A well-defined intrauterine gestational sac could be seen at 4 weeks and 1 to 4 days of menstrual age. The beta-subunit of human chorionic gonadotropin level at this time was 450 to 750 mlU/ml. Structures such as the yolk sac, membranes, ventricular system in the brain, musculoskeletal system, and cord were described and illustrated. Textbooks and atlases were used for comparative purposes. High-resolution transvaginal sonography will facilitate first-trimester perinatology.

Effect of amniotic membrane rupture on length of labor.

Between January 1, 1979, and December 21, 1982, 2564 medically and obstetrically normal patients, admitted to the hospital with intact amniotic membranes during the latent phase of labor, were matched for spontaneous or artificial rupture of the membranes at similar cervical dilations. Spontaneous rupture of the membranes occurred earlier and was more likely in the latent phase of labor than was artificial rupture of membranes, which tended to occur nearer to or in the active phase of labor, and at lower pelvic stations. When matched by cervical dilation, spontaneous membrane rupture was associated with more rapid cervical dilation. Stepwise regression analysis confirmed that membrane rupture had a significant but small effect on labor length and rate of cervical dilation. Pelvic station and maternal parity had a smaller association with labor length than did membrane rupture. Cervical dilation at the time of membrane rupture appeared to be the most important factor associated with the length of labor.

Decreased fetal movements with sustained maternal hyperglycemia using the glucose clamp technique.

The purpose of this study was to evaluate the effect of sustained maternal hyperglycemia (120 mg/dl) on fetal activity. The glucose infusion study group was comprised of nine healthy gravidas between 36 and 40 weeks' gestation, and six patients served as controls. The protocol design included an overnight fast for all patients. Fetal movements were evaluated by external fetal monitoring. A 2-hour preinfusion evaluation of fetal activity served as the baseline control for each patient studied. Study patients then received a glucose infusion by a glucose clamp technique to maintain a sustained hyperglycemia of 120 mg/dl for 3 hours. After the glucose infusion, fetal movements were observed for 1 hour. Control patients received a saline infusion for 2 hours after a 2-hour baseline evaluation. Maternal hyperglycemia was associated with a significant decrease of fetal movements greater than 1 second duration during the first hour of glucose infusion. Fetal movements returned to baseline during the second and third hours of glucose infusion. Saline infusion was not associated with a decrease in fetal activity. We conclude that sustained maternal hyperglycemia is associated with a transient decrease in fetal movement during the first hour of glucose infusion followed by a return to the control (preinfusion) level of fetal activity. These data may have implications in the study of fetal behavior in diabetes mellitus.

Transition from latent to active labor.

The transition from the latent to the active phase of labor, as defined by Friedman, was studied in all noncomplicated patients over a four-year period. Mothers studied were in spontaneous labor with a singleton fetus in the vertex position with intact membranes at admission. The independent variables were the parity and vaginal examination data, and the dependent variable was the rate of cervical dilation. The transition from latent to active labor was recorded and stratified by the cervical dilation where it occurred in a sample population consisting of 1060 nulliparous and 639 primiparous or multiparous women. There were no differences between nulliparous and multiparous patients. Less than 50% of labors became active by the time the cervixes had reached 4-cm dilation. By 5 cm, 74% of labors were active. However, when protracted and arrested labors were eliminated, 60% of the patients had reached the latent-active transition by 4 cm and 89% by 5 cm. We concluded that once a normal patient has reached 5 cm, she should be in the active phase of labor. If not, there is a high probability of labor dystocia.

Prenatal and perinatal factors associated with brain disorders.

In April 1985, a report entitled "Prenatal and Perinatal Factors Associated with Brain Disorders" was published by the National Institutes of Child Health and Human Development and the National Institute of Neurological and Communicative Disorders and Stroke. A panel of ten individuals completed the report documenting the knowledge and the complexities of what is known with respect to brain damage that may develop before birth or in the neonatal period. It is clear that all stages of fetal and neonatal development influence normal outcome. Although intrapartal period events may explain a significant portion of cerebral palsy, the illness is often linked with confounding factors such as low birth weight and asphyxia. Pure epilepsy or pure mental retardation is rarely associated with intrapartal events. In general, the pathologic lesions seen in the brain may reflect many different fetal insults. The same clinical event such as asphyxia may result in varied intracranial diseases, which effects may depend on when the clinical events occurred.

Assessment of developmental time periods and risks of brain damage in the fetus and neonate.

The life cycles of 18 infants with neurologic morbidity were divided into antepartum, intrapartum, neonatal and infant time periods. Specific events related to risks for each infant were assigned to these periods. In almost all the children multiple, rather than single, fetal, neonatal and infant risks were found, and along with the multiple risks, multiple time periods were found during which the risks occurred. It is difficult, and often impossible, to relate infant neurologic morbidity to a single event or time period.

Midforceps deliveries: long-term outcome of infants.

Infants delivered by midforceps between 1976 and 1982 were evaluated for evidence of developmental delay or neurological deficit by chart review. The 110 infants who were followed for at least 2 years were compared to a matched group of infants delivered by cesarean section. The cesarean section group was matched for the immediate indication for delivery (dystocia or fetal distress), birth weight, gestational age, sex, and race. There was no significant difference in abnormal outcomes in the two groups.

Trends in the frequency of cesarean births.

While the actual cesarean birth rate may still be increasing, it appears that the rate of increase is not as extreme. Perhaps this can be expressed as a trend. A recent study has demonstrated the ability to decrease the primary cesarean section rate without adverse perinatal effects. Confirmation that the cesarean birth rate is not necessarily linked to perinatal mortality is available from the Dublin report, in which the authors note that the trend in cesarean birth rates can be altered by a different approach to the management of labor. While still speculative, it appears that public concern and physician attitudes may soon be reflected in a trend toward decreasing cesarean birth rates.

Latent phase of labor in normal patients: a reassessment.

The vaginal examination data (dilation, station, and time) were examined from 2845 consecutive uncomplicated patients who were admitted in early labor to Cleveland Metropolitan General Hospital between January 1, 1979 and December 31, 1982, using data from the computer database of the Perinatal Clinical Research Center. The length of the latent phase of labor was calculated in 2479 of these patients to form the study group. Individual effects of parity and the cervical dilation on the length of the latent phase of labor resembled Friedman's results from 20 years ago. Furthermore, the average and prolonged lengths of the latent phase confirmed that labors have not changed appreciably in 20 years. However, multivariable analysis and standard stepwise regression on all of the vaginal examination data revealed that the largest influence on the length of latent labor was the admitting cervical dilation. Parity had only a small effect when cervical dilation was controlled. Thus, a multiparous patient may progress as slowly as a primiparous patient if they both are admitted with a low cervical dilation.