Birth weight as a predictor of brachial plexus injury

OBJECTIVE

To examine the relationship between birth weight and brachial plexus injury and estimate the number of cesareans needed to reduce such injuries.

METHODS

All 80 neonatal records coded for brachial plexus injury from October 1985 to September 1993 at the Brigham and Women's Hospital in Boston, Massachusetts, were studied along with linked maternal files. Birth weight, method of delivery, presence or absence of shoulder dystocia, and any diagnosis of maternal gestational or nongestational diabetes were abstracted. Data for the group with brachial plexus injury were compared with data for live-born infants without this injury during the same period. The sensitivity and specificity of birth weight as a predictor of brachial plexus injury were calculated. Further, the number of cesarean deliveries necessary to prevent a single brachial plexus injury was estimated using various weight cutoffs (4000, 4500, and 5000 g) for elective cesarean delivery.

RESULTS

Among 77,616 consecutive deliveries, there were 80 brachial plexus injuries identified, for an incidence of 1.03 per 1000 live births. The incidence of brachial plexus injury increased with increasing birth weight, operative vaginal delivery, and the presence of glucose intolerance. In the group of women without diabetes, between 19 and 162 cesarean deliveries would have been necessary to prevent a single immediate brachial plexus injury. Among women with diabetes, between five and 48 additional cesareans would have been required.

CONCLUSION

Although birth weight is a predictor of brachial plexus injury, the number of cesarean deliveries necessary to prevent a single injury is high at most birth weights. Because of the large number of cesarean deliveries needed to prevent a single brachial plexus injury in infants born to women without diabetes, it is difficult to recommend routine cesarean delivery for suspected macrosomia in these women.

Abrupt onset of severe pain at term. A case report

This case report involves an adolescent primigravida at term who was admitted with urinary complaints to the labor and delivery unit of a medical center. Within an hour, she suddenly began screaming and complaining of severe pain running from her anterior pelvis through her vagina and up her spine. Three days of very challenging co-management of the patient, with several recurrences of acute pain, followed. Differential diagnoses that could explain this patient's symptoms are reviewed and discussed. Difficult management issues, including the stress of clinical management in the face of unidentified disease processes, are addressed. Lacking a certain diagnosis even retrospectively, the authors request comments from readers.

Peritonitis associated with passage of the placenta into the abdominal cavity in a llama

Following parturition, a female llama was admitted to our hospital with a tear in the dorsal area of the vagina and peritonitis. The llama was clinically normal for 7 days after which its condition started to deteriorate, and the llama died 11 days after admission. On necropsy examination, the intact placenta was found in the abdominal cavity. Therefore, we suggest that in llamas with vaginal tears after parturition, it may be useful to immediately secure the fetal membranes with umbilical tape to the outside of the llama to ensure that the placenta will pass through the vulva. Additionally, in llamas with uterine or vaginal tears in which a retained placenta is suspected but cannot be identified in the uterus, exploratory laparotomy should be performed immediately, even if the llama appears clinically normal.

Obstructed labor injury complex: obstetric fistula formation and the multifaceted morbidity of maternal birth trauma in the developing world

Prolonged obstructed labor may produce injuries to multiple organ systems. The best known, and most common, of these injuries is obstetric fistula formation. When obstructed labor is unrelieved, the presenting fetal part is impacted against the soft tissues of the pelvis and a widespread ischemic vascular injury develops that results in tissue necrosis and subsequent fistula formation. Unlike the postsurgical vesicovaginal fistula, however, which is usually the result of focal trauma to otherwise healthy tissues, the obstetric fistula is the result of a "field injury" to a broad area. The field injury that is produced by prolonged obstructed labor may result in multiple birth-related injuries in addition to (or instead of) a vesicovaginal fistula. Focusing simply on the "hole" between the bladder and the vagina ignores the multifaceted nature of the injury that many of these patients have sustained. These injuries may include total urethral loss, stress incontinence, hydroureteronephrosis, renal failure, rectovaginal fistula formation, rectal atresia, anal sphincter incompetence, cervical destruction, amenorrhea, pelvic inflammatory disease, secondary infertility, vaginal stenosis, osteitis pubis, and foot-drop. In addition to their physical injuries, women who have experienced prolonged obstructed labor often develop serious social problems, including divorce, exclusion from religious activities, separation from their families, worsening poverty, malnutrition, and almost unendurable suffering. Isolated almost exclusively to the developing world, particularly Africa, this problem has not received the international attention that it deserves, from either a medical or a social standpoint.

Risk factors and fetal outcome in cases of shoulder dystocia compared with normal deliveries of a similar birthweight

OBJECTIVES

To compare risk factors and fetal morbidity in deliveries complicated by shoulder dystocia with deliveries of similar infant birthweights but not complicated by shoulder dystocia.

DESIGN

A retrospective case-controlled study.

SETTING

Kuwait Maternity Hospital.

PARTICIPANTS

Sixty-nine cases of true shoulder dystocia and 138 controls matched for exact infant's birthweight.

METHODS

Demographic data and data regarding history of previous shoulder dystocia, diabetes mellitus, labour course, method of delivery and newborns' condition were collected from patients and case notes following delivery. The mothers' height and weight were measured. Oral glucose tolerance test were performed on patients who were not known as diabetics. The infants' head and chest circumferences and bisacromial diameter were measured.

RESULTS

There were no significant differences between cases and controls when mean age, parity, height, weight and gestational ages were compared. The cases demonstrated a higher incidence of previous shoulder dystocia (P < 0.01), diabetes mellitus (P < 0.001), use of oxytocin for acceleration of labour (P < 0.01) and operative vaginal deliveries (P < 0.01). Differences between cases and controls in their newborn infants' head and chest circumferences were not significant, but the newborns of cases have a longer mean bisacromial diameter and a shorter head circumference:bisacromial diameter ratio (P < 0.001 and P < 0.001, respectively). Thirty-seven infants (53.6%) from cases and two from controls (1.4%) sustained birth injuries. There were two stillbirths among the cases.

CONCLUSIONS

Although fetal macrosomia is the principal risk factor for shoulder dystocia, other important risk factors include diabetes mellitus, previous history of shoulder dystocia, prolonged labour, delay in the second stage of labour and fetal shoulder width which appear to be independent of fetal weight.

Risk of uterine rupture after the partographic 'alert' line is crossed--an additional dimension in the quest towards safe motherhood in labour following caesarean section

To determine if prolonged active phase of labour is associated with increased risk of uterine scar rupture in labour following previous lower segment caesarean section, a retrospective cohort study (1988-91) was done to analyse active phase partographs of 236 patients undergoing trial of labour following caesarean section, 7 (3%) of whom had scar rupture. After onset of active phase (3 cm cervical dilatation), a 1 cm/h line was used to indicate "alert". A zonal partogram was developed by dividing the active phase partographs into 5 time zones: A (area to the left of "alert" line), B (0-1 h after "alert" line), C (1-2 h after "alert" line), D (2-3 h after "alert" line) and EF (> 3 h after "alert" line). The relative risk of uterine scar rupture was calculated for different partographic time zones. The relative risk of uterine scar rupture was 10.5 (95% confidence interval 1.3-85.5, p = 0.01) at 1 hour after crossing the "alert" line; 8.0 (95% confidence interval 1.6-40.3, p = 0.009) at 2 hours after crossing the "alert" line; and 7.0 (95% confidence interval 1.6-29, p = 0.02) at 3 hours after crossing the "alert" line. In women undergoing trial of labour following caesarean section, prolonged active phase of labour is associated with increased risk of uterine rupture. A zonal partogram may be helpful in assessing this risk in actively labouring women who cross the partographic "alert" line.

Medico-legal aspects of brachial plexus injury: the obstetrician's point of view

The author reviews the obstetric literature with regard to factors predisposing to or predicting the occurrence of brachial plexus injury in the newborn. Based on the evaluated data, it is concluded that, whereas there are identifiable predisposing factors for shoulder dystocia, to which the occurrence of brachial plexus injury is widely attributed, the predictive power of the various identifiable factors is generally low. The writer also quotes literary data which suggest that injury to the brachial plexus may occur in utero before labor and, thus, unrelated to arrest of the shoulders during the process of delivery. The contemporary literature contains diverse and often contradictory opinions which do not provide clear-cut guidelines for the practicing obstetrician for the prevention of brachial plexus injury. In some parts of the world a disproportionately large number of malpractice claims against obstetricians derive from such injuries. Therefore, the formulation of a consensus concerning the definition of shoulder dystocia, the identification of preventive measures to be utilized to avoid its occurrence and the required clinical management in case of arrest of the shoulders are unresolved problems that the medical profession needs to address.

Are labor abnormalities more common in shoulder dystocia?

OBJECTIVE

Our objective was to determine the association between labor abnormalities and shoulder dystocia.

STUDY DESIGN

All consecutive cases of shoulder dystocia from January 1986 to August 1994 were reviewed (n = 276). For purposes of comparison a control group of vaginally delivered patients was randomly selected in a 2:1 ratio (n = 600). Charts were reviewed for demographic information, labor and delivery events, and neonatal outcome.

RESULTS

Labor abnormalities were comparable in the shoulder dystocia and control groups, both in the active phase and in the second stage. When patients with diabetes and those with macrosomic infants were analyzed separately, no significant differences in labor abnormalities were identified. The rate of operative vaginal delivery was significantly higher in the shoulder group, and one third of the operative deliveries were midpelvic. In addition, the induction rate was higher in the shoulder group.

CONCLUSIONS

Our data suggest that labor abnormalities may not serve as clinical predictors for subsequent development of shoulder dystocia, thus emphasizing the unpredictability of this condition.

Shoulder dystocia--is it predictable?

An unmatched comparative study is described to determine if routine clinical indicators are useful predictors for shoulder dystocia. Parity, maternal weight gain during pregnancy, and a history of a previous large baby and increased operative vaginal delivery rate were more often associated with shoulder dystocia. No other significant associations were found. However, shoulder dystocia can not be predicted accurately antepartum using routinely available clinical factors.

Shoulder dystocia. Report of 2 cases and review of the literature

Shoulder dystocia, or impacted shoulders is an infrequently encountered obstetric emergency. Despite various risk factors identified by investigators, the occurrence of shoulder dystocia is difficult to predict. Two cases of severe shoulder dystocia managed personally by the author are presented. These cases illustrate some of the important issues regarding prediction of shoulder dystocia and the need to begin a series of well-tested manoeuvres immediately, to successfully deliver the baby.

Emergent management of shoulder dystocia

It is clear that in the vast majority of cases, shoulder dystocia cannot be predicted by the physician. Although macrosomia is strongly associated with shoulder dystocia in retrospective analyses, there are no clinical or sonographic parameters that can reliably and prospectively identify the individual macrosomic fetus. Furthermore, more than 98% of patients with macrosomic fetuses who deliver vaginally do not have shoulder dystocia. Some investigators have advocated the use of cesarean delivery for suspected macrosomic fetuses to avoid potential birth trauma during vaginal delivery; however, this strategy has not been shown to be beneficial in the majority of cases. Boyd and colleagues report that an increase in the cesarean delivery rate for suspected macrosomia from 8% in the 1960s to 21% in 1980 did not improve overall perinatal outcome among macrosomic infants. Since 50% to 90% of cases of shoulder dystocia occur in normally grown fetuses, cesarean delivery for all suspected macrosomic fetuses would not be expected to prevent the vast majority of cases of shoulder dystocia and would expose many mothers to a substantially increased risk for morbidity and mortality. Management of this complex problem requires clinical judgment by the well-trained physician and individualized care for each patient. Because shoulder dystocia remains unpredictable in almost all cases, when it does occur it must be managed expeditiously but carefully with one or more of the maneuvers described. The sequence of manipulations reported herein represents one way of managing shoulder dystocia (Fig. 11). As noted before, however, there are no data to support improved efficacy of one particular sequence over another. The sequence of maneuvers chosen by the clinician should be based on the algorithm with which he or she is most familiar and which has proven successful in their hands. Permanent injury to the fetus fortunately is rare but does occur even in the well-managed case.

[Anatomic findings during 509 microscopic sphincteroplasties for urinary stress incontinence in women. Diagnostic and surgical consequences]

Stress incontinence of urine without cervicocystoptosis secondary to difficult labor and delivery is essentially due to rupture of the smooth muscle sphincter of the bladder. Other changes affecting the anterior vaginal wall (thinning of fibrous tissue, partial splitting of the striated urethral sphincter, etc.) are found before difficult labor without stress incontinence of urine. Only operative microscopy enables anatomical analysis. Lateral cystography confirms the clinical diagnosis. There is no correlation between the extent of lesions and functional study results. Surgery is limited to the dissection and apposition of the residual zone of the smooth muscle sphincter retracted laterally. There were neither postoperative dysuria nor dyspareunia. There were 11 recurrences. No marked symptomatic change 5 years later.

Tracheal collapse

Tracheal collapse in calves usually is associated with dystocia at birth, especially breech presentations. Inspiratory dyspnea typically is seen within the first several months of life and may worsen progressively. Lateral cervical radiographs are useful in defining the affected segments as well as identifying previously fractured ribs. Surgical stenting of the trachea will improve the calf's condition, but because this procedure is done on young calves, the tracheal diameter of the affected segment is permanently limited by the size of the prosthesis.

The Zavanelli maneuver for relief of abdominal dystocia associated with gastroschisis

A patient with acute hydramnios and advanced preterm labor at 34 weeks was seen after gastroschisis had been diagnosed by second-trimester fetal ultrasonography. The fetus also had meconium peritonitis and acute ascites. The distended abdomen did not decompress spontaneously during the second stage of labor. Severe abdominal dystocia was resolved with the Zavanelli maneuver (cephalic replacement) and cesarean delivery. This is the first reported use of the Zavanelli maneuver for abdominal dystocia.

Fractured clavicle is an unavoidable event

OBJECTIVES

The three purposes of this study were to determine the incidence of fractured clavicle in newborns delivered at our hospital, to identify preventable risk factors associated with these fractured clavicles, and to identify the acute sequelae of fractured clavicle in these infants.

STUDY DESIGN

We performed a retrospective chart review of all women delivered during an 8-month period. Newborns with radiologically proved fractured clavicles were compared with a control group of infants delivered immediately before and immediately after the study patient. Maternal, labor, delivery, and newborn factors were analyzed statistically.

RESULTS

A fractured clavicle occurred in 0.9% (34/3880) of vaginally delivered newborns; none occurred with an abdominal delivery. The only statistically significant risk factors were gestational age, shoulder dystocia, and newborn weight. No infant with fractured clavicle had a 5-minute Apgar score < 7, an abnormal cord blood pH, or an abnormal neurologic examination.

CONCLUSIONS

We did not identify a specific perinatal factor that can be changed to avoid clavicle fracture. The injury appears to be an unavoidable event without permanent sequelae. Thus it is not an indicator for quality improvement.

Management of anticipated and actual shoulder dystocia. Interpreting the literature

Shoulder dystocia is a rare but serious obstetric complication that can result in significant neonatal and maternal morbidity and in costly litigation. Conflict exists in the literature regarding definition, incidence, predictability and preventability, relationship to neonatal injury, and appropriate management models. Anticipatory clinical interventions for potential shoulder dystocia have included ultrasound assessment of macrosomia; elective induction of labor; elective caesarean section; altered place of birth; and generous episiotomy/episioproctotomy. The authors note that these interventions often conflict with client desires and nurse-midwifery philosophy of birth, generate significant risks and costs in themselves, and do not address the poor predictability of shoulder dystocia. In recent literature, the safety and efficacy of maternal position change maneuvers (such as McRoberts maneuver, hands-knees position, and squatting) have been presented as methods to resolve most cases of shoulder dystocia. Despite the success of these more benign, external maneuvers, the episiotomy mandate remains in nearly all obstetric and midwifery texts and handbooks (1-8) and journal references (9-19). A literature review of related professional disciplines was undertaken to study these conflicts and to identify support for applying a philosophy of minimal, appropriate intervention to the complex issue of shoulder dystocia.

Inter-relationships of periparturient diseases in dairy cows

The associations between periparturient diseases in 3603 lactations over three calving seasons were assessed on 10 dairy farms in the south west of England by using logistic regression. Calf mortality and dystocia were strongly associated. Twinning and dystocia were important predictors of calf mortality. Twinning was also a significant predictor for retained fetal membranes. Retained fetal membranes, twins, calf mortality and dystocia, in that order of importance, were risk factors for vulval discharge. Twinning, dystocia, retained fetal membranes and lameness before service increased the risk of mastitis before service. Similarly, mastitis and dystocia before service increased the risk of lameness before service. Oestrus was less likely to be observed in cows that had twinned or suffered lameness before service, the latter having a significantly greater influence in first calvers than older cows.

Disseminated B virus infection in a cynomolgus monkey

A cynomolgus monkey (Macaca fascicularis) was euthanatized 1 week following dystocia because of severe peritonitis. Histologic examination revealed lesions characteristic of herpesvirus infection in lungs, liver, spleen, bone marrow, uterus, and adrenal gland, and on the serosal surface of intestines, pancreas, and reproductive tract. Immunohistochemical studies on liver and lungs revealed Herpes B-like antigens in the lesions. B virus was isolated from serum. As systemic B-virus infection was not diagnosed before death of the monkey, these findings underscore the need for universal precautions when handling blood, fluids, or tissues from macaques.

Risk factors for downer cow syndrome

A nested case-control study to detect risk factors for the development of the downer cow syndrome 30 d postpartum was conducted. Records from 2705 lactations from 12 Holstein dairy herds in the vicinity of Cornell University were collected prospectively between March 1981 and April 1985. Logistic regression was used to model the risk factors for downer cow syndrome. No confounding or modification effect by season of calving and parity was detected. The cumulative postpartum incidence rate for downer cow syndrome was 1.1%. Clinical hypocalcemia and stillbirth increased the risk of downer cow syndrome fivefold. An interaction term existed between dystocia and retained placenta.

Causes of abortion, stillbirth, and perinatal death in horses: 3,527 cases (1986-1991)

Pathology case records of 3,514 aborted fetuses, stillborn foals, or foals that died < 24 hours after birth and of 13 placentas from mares whose foals were weak or unthrifty at birth were reviewed to determine the cause of abortion, death, or illness. Fetoplacental infection caused by bacteria (n = 628), equine herpesvirus (143), fungi (61), or placentitis (351), in which an etiologic agent could not be defined, was the most common diagnosis. Complications of birth, including neonatal asphyxia, dystocia, or trauma, were the second most common cause of mortality and were diagnosed in 19% of the cases (679). Other common diagnoses were placental edema or premature separation of placenta (249), development of twins (221), contracted foal syndrome (188), other congenital anomalies (160), and umbilical cord abnormalities (121). Less common conditions were placental villous atrophy or body pregnancy (81), fetal diarrhea syndrome (34), and neoplasms or miscellaneous conditions (26). A diagnosis was not established in 16% of the cases seen (585). The study revealed that leptospirosis (78) was an important cause of bacterial abortion in mares, and that infection by a nocardioform actinomycete (45) was an important cause of chronic placentitis.