An objective definition of shoulder dystocia: prolonged head-to-body delivery intervals and/or the use of ancillary obstetric maneuvers

OBJECTIVE

To generate an objective definition of shoulder dystocia by timing the events of the second and third stages of labor, and to define the true incidence of shoulder dystocia.

METHODS

In 34 arbitrarily selected 24-hour time periods, a nonparticipating observer prospectively timed intervals of the second stage of labor in all vaginal deliveries and recorded the use of obstetric maneuvers (McRoberts, episiotomy after delivery of the fetal head, intentional extension of initial episiotomy after delivery of the fetal head, suprapubic pressure, posterior arm rotation to an oblique angle, rotation of the infant by 180 degrees, delivery of the posterior arm, and general anesthesia) and whether the obstetric attendant identified a delivery with shoulder dystocia. All data are reported as mean +/- standard error of the mean.

RESULTS

Two hundred fifty deliveries were timed and recorded prospectively. Mean intervals (in seconds) in nonmaneuver patients were as follows: head to anterior shoulder 14.8 +/- 1.0, anterior to posterior shoulder 3.9 +/- 0.6, posterior shoulder to body 5.4 +/- 0.8, and total head-to-body time 24.2 +/- 1.3. Three groups of patients were defined after delivery. The maneuver group consisted of 27 patients requiring any of the aforementioned obstetric maneuvers, although the obstetric attendant identified only 16 of these as shoulder dystocia. The prolonged delivery group included 29 patients with the head-to-body delivery interval exceeding the mean plus two standard deviations (60 seconds) of nonmaneuver patients. Sixteen of the 27 maneuver patients were identified as prolonged. The 210 not identified as maneuver or prolonged were considered to be normal. Normal patients had a significantly lower newborn birth weight (3269 +/- 38 g), and a lower proportion of 1-minute Apgar scores of 7 or less (11%) than did the maneuver (4247 +/- 86 g, 41%) and prolonged groups (3952 +/- 118 g, 34%). Defining shoulder dystocia as a prolonged head-to-body delivery time and/or the use of obstetric maneuvers identified 40 patients who had birth weights and 1-minute Apgar scores significantly different from the normal patients.

CONCLUSION

The incidence of shoulder dystocia, as defined by the use of ancillary obstetric maneuvers, is higher than that reported previously, and the reporting of shoulder dystocia appears to be unreliable. The interval from head-to-body delivery is delayed significantly in patients with shoulder dystocia, despite the lack of recognition of shoulder dystocia. We propose defining shoulder dystocia as a prolonged head-to-body delivery time (eg, more than 60 seconds) or the need for ancillary obstetric maneuvers.

[Frequency and determinants of episiotomy in second-line obstetrics in The Netherlands]

OBJECTIVE

To study factors that influence the probability of episiotomy in Dutch gynaecologist-supervised deliveries.

SETTING

Obstetric units of Dutch hospitals.

DESIGN

Observational study.

METHODS

Data of 65,313 gynaecologist-supervised, vaginal deliveries of live-born singletons registered in the Dutch National Obstetric Database of 1990, were used. Firstly, the effect of characteristics of the mother, the child, the pregnancy, and the delivery on the probability of episiotomy were assessed in univariate analyses. Subsequently logistic regression analysis was used to determine the effect of each variable, while adjusting for the other variables.

RESULTS

The episiotomy rate in the total group of gynaecologist supervised deliveries was 39%. In the subgroup of vaginal deliveries of live born singletons, the rate was 46%. Besides the well-known risk factors such as parity, instrumental delivery and length of second stage of labour, ethnicity was also found to have an independent effect on the risk of an episiotomy. Mediterranean, Creole and Hindu women had a lower episiotomy risk than Dutch women (OR: 0.47 and 95% CI: 0.44-0.51). Gynaecologists more often performed episiotomy than midwives, after adjusting for possible confounding factors (OR: 1.54; 1.46-1.63). In University hospitals fewer episiotomies were performed than in large non-university hospitals (OR: 0.81; 0.76-0.87.

CONCLUSION

The decision to perform episiotomy appears not to depend solely on factors related to perineal rupture or foetal complications. The probability of episiotomy is also influenced by attendant at delivery and type of hospital.

Intrapartum bimanual tocolytic-assisted reversal of face presentation: preliminary report

OBJECTIVE

To design and conduct a mode of vaginal delivery for mentoposterior-presenting fetuses when cesarean delivery is not possible.

METHODS

Eleven orthodox Jewish parturients who refused cesarean delivery had intrapartum bimanual conversion of mentoposterior to occipitoanterior presentation, concomitant with ritodrine infusion in ten.

RESULTS

Excluding the first case, in which ritodrine was not administered, the maneuver was successful and vaginal delivery was achieved.

CONCLUSION

This maneuver, performed with intravenous ritodrine tocolysis, might be an alternative mode of delivery in the presence of mentoposterior presentation when cesarean delivery is not possible. More experience is needed with this technique before it is performed routinely.

Survey of forceps delivery in North America in 1990

OBJECTIVE

To determine whether opinions and practice patterns have markedly changed over the past decade and whether clinicians are cognizant of the new ACOG definitions for forceps deliveries.

METHODS

Two hundred ninety-five United States and Canadian residency programs were surveyed via a questionnaire; 203 (69%) responded. Statistical analysis was performed using the chi 2 test, Yates correction factor, and the extended Mantel-Haenszel test.

RESULTS

All but two program directors (99%) were familiar with the new definitions, which were being used by 162 (80%) of the programs. All institutions used outlet and low forceps, although 14% no longer performed midforceps deliveries. Attending faculty were the primary instructors in 67% of United States and 100% of Canadian programs. Simpson forceps were the most commonly used for outlet (46%) and low (43%) forceps deliveries. Kielland (27%) and Simpson (24%) instruments were most commonly used for midforceps deliveries.

CONCLUSION

Although the rate of midforceps use decreased, operative vaginal delivery was still commonly taught in residency programs in North America in 1990.

The diagnosis and management of dystocia of the shoulder

Dystocia of the shoulder is an unpredictable obstetric emergency that may result in injury to the mother or fetus. In an effort to reduce such risks, attempts have been made to identify patients having a fetus who may subsequently develop shoulder dystocia. The literature, however, clearly reflects that even the combination of prenatal historic facts, estimated fetal weight and sequence of intrapartum events is ineffective in prospectively identifying infants whose births are complicated by shoulder dystocia. During a ten year period at the University of Mississippi Medical Center, the incidence of macrosomia, shoulder dystocia and subsequent brachial plexus injury was reviewed. The majority of instances (89 percent) of shoulder dystocia occurred in patients weighing less than 8 pounds 13 ounces at birth. In the current retrospective review, only 11 percent of the women had risk factors for macrosomia or shoulder dystocia and among these, none were identified prospectively. Additionally, 91 percent of patients with brachial plexus injury recovered with no sequelae. One instance of brachial plexus injury occurred at the time of cesarean section. These data reveal that macrosomia and subsequent shoulder dystocia cannot be predicted. Therefore, it is not feasible to prevent brachial plexus injury prospectively by prophylactic cesarean section. Great clinical acumen and technical expertise by the obstetrician using a variety of methods may be useful in avoiding, as much as possible, injury to the mother and fetus when shoulder dystocia does occur.

Operative vaginal delivery. ACOG Technical Bulletin. Number 152--February 1991

With any operative vaginal delivery, it is important to document in the medical record the indications for the procedure, including the position and station of the vertex and specifics of technique, timing, and ease of the procedure. The use of cord pH and blood gas determinations may be helpful for further evaluation of the fetus.

Instrumental (operative) vaginal deliveries: vacuum extraction compared with forceps delivery at Ilorin University Teaching Hospital, Nigeria

In a four-year period (1984 to 1987) a total of 141 Nigerian women who had instrumental vaginal deliveries at term in the Obstetric unit of University of Ilorin Teaching Hospital, Ilorin, were studied. Out of this number 79 had forceps delivery while 62 had vacuum extraction. The forceps delivery rate had fluctuated between 0.11% and 0.46% while the vacuum extraction rate had steadily increased from 0.08% to 0.39% (Table 1) in our unit over the 4-year period. With the exception of fetal distress, there were no significant differences found in the indications for forceps delivery and vacuum extraction. The preapplication station, position and cervical dilatation differ in both groups (Table 4). There was less maternal trauma in vacuum extraction than forceps (Table 5). The vacuum extraction was more associated with cephalhaematoma and neonatal jaundice but less with neonatal mortality compared with forceps (Table 7). Vacuum extraction had gradually assumed more prominence as an alternative to midforceps delivery in our unit in the study period. There was no maternal mortality in the two groups.

[Relations between psycho-physical acceleration and modern obstetrics]

In the highly developed countries, an acceleration of human growth and an increase in body length can be observed. The weight and length at birth are also increasing, which can be proved by our own investigation. Up to now, the theories explaining this phenomena are insufficient, because they assume the transmission of genetically acquired qualities. The reason for the acceleration is to be considered in the advancement of obstetrics as follows: Obstetrical handling, forceps and caesarean section permit the delivery of large babies, which were often lethal for mother and child. This led to an increase in the frequency of genetic developments for greater body length and weight at birth, which had formerly been limited by the high mortality rate. The trend towards larger babies is caused by an evolutionary selection of an enlargement of the brain, which must reach a certain minimum size by the time of birth. The relative enlargement of the newborn skull, made possible by advanced obstetrics, permits such increased birth weight and length. It also leads to an acceleration of growth and taller adults. The consequence of larger babies is an increasing frequency of obstetrical operations.

Dilation and evacuation for second-trimester genetic pregnancy termination

Dilation and evacuation (D&E) is the most common procedure for second-trimester pregnancy termination currently used by United States obstetrician-gynecologists. Although this method carries morbidity and mortality rates significantly lower than methods requiring labor induction, the procedure most commonly used for second-trimester genetic terminations seems to be labor induction (eg, vaginal prostaglandin suppositories). Many geneticists appear reluctant to recommend D&E over induction methods of pregnancy termination because they perceive that fetal abnormalities cannot be consistently confirmed by evaluation of the products of conception obtained by D&E. We report here 60 consecutive patients who underwent D&E (14-22 weeks' gestation) after detection of fetal abnormalities. The prenatal diagnoses were confirmed in all cases. Our experience thus indicates that D&E is reliable in confirming most prenatal diagnoses and should be the procedure of choice when second-trimester pregnancy termination is chosen because of fetal abnormalities.

[Risk assessment of active obstetrical intervention in relation to delivery time interval in the control of vaginal twin delivery]

In connection with the vaginal delivery of twins, different opinions exist among obstetricians as to whether the time interval between the birth of both twins influences the often reported higher perinatal mortality and morbidity of the second twin. During the period from January 1, 1982, to December 12, 1987, we had 176 twin deliveries (1.5%), among a total number of 11,395, from which, after vaginal birth of twin A, in 96 cases twin B was born alive. In this study group, we analysed retrospectively our active obstetrical management in respect of relations between time interval on the one hand and perinatal mortality, operation frequency and foetal outcome of the second born twin on the other. The perinatal mortality rate, as defined by the WHO was 4.2% and excluding stillborns and children with a birth weight of less than 1,000 g, only 0.3%. We could not identify the influence of the time interval on perinatal mortality, which was equal for both twins. The frequency of surgical interventions rose from 12.8% when twin B was born within 20 min, to 38.8% when it was delivered after this time interval. An adverse foetal outcome judged by APGAR-score could not be proved. Shortening the time interval by active obstetrical management is of value in order to reduce potential risks for the mother and the second born twin, but it should be borne in mind, that the results of our study are positively influenced by the primary selection criteria of mode of delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervagem/Dilapan for preoperative cervical dilatation prior to vacuum aspiration for termination of first trimester pregnancy. A prospective randomized study

The present study included 40 healthy nulliparous women admitted to the hospital for termination of first trimester pregnancy. The patients were randomly allocated to two study groups. One group was treated for 4 hours with one 1 mg Cervagem vaginal suppository prior to vacuum aspiration, the other was treated 4 hours with a Dilapan osmotic dilator intracervically. The patients were continuously supervised during treatment and after operation. Side effects and analgesic consumption were recorded. At operation the degree of cervical dilatation, blood loss and operative complications was registered. Dilapan was more effective and more uniform in dilating the cervix (p less than 0.05) and eventual further dilatation was easier (p less than 0.05). The blood loss was higher in the Dilapan-treated group (p less than 0.05). Side effects of postoperative pain and use of analgesic injections were higher in the Cervagem group (p less than 0.05). It is concluded that both methods are effective in dilating the cervix prior to vacuum aspiration, with Dilapan being the more effective dilator with the lower frequency of side effects.

Vacuum extraction

Vacuum extraction rivals forceps delivery in efficacy, is less traumatic to the mother and is as safe or safer than forceps delivery for the infant. Soft plastic cup extractors minimize the technical, maternal and fetal problems of vacuum extraction and have made this method of delivery ideal for the family physician who practices obstetrics.

Barton's forceps deliveries at Paarl Hospital

Experience in using Barton's forceps for mid-pelvic arrest of the fetal head in 348 cases has proved that this instrument is both easy to apply and safe for the baby, provided rigid adherence to safety criteria are observed. As modern obstetric practice is favourably disposed towards mid-pelvic forceps vaginal delivery, the particular advantages of Barton's forceps should be more widely extolled. Their use is an invaluable addition to the obstetrician's armamentarium. Training in their use should, however, be thorough and extensive and under the guidance of a skilled senior obstetrician.

Birth progression and traction forces developed under vacuum extraction after slow or rapid application of suction

A vacuum extraction recorder was used to provide an objective measure of the traction forces developed on the fetal head during 120 vacuum extractions. In half of the deliveries the vacuum was gradually and stepwise increased to -0.8 kg/cm2 before traction. In the others, a rapid application of vacuum to the same level was chosen. No significant difference could be recorded in the traction forces developed by the different methods. In fact, once an adequate level of vacuum had been achieved, high degrees of traction could be applied to the suction cup, regardless of the rate at which the vacuum was developed. Furthermore, the number and nature of neonatal complications were not influenced by the method chosen.

[Is rotation in vacuum extraction possible?]

Vacuum extraction is a traction instrument and hardly suitable for accomplishing rotation. This assumption is disproved by means of two new suction cups that are being used in China. These suction cups and their use are described together with the relevant indication.

Obstetric vacuum extraction

A brief historical review of vacuum extraction, indications for use, safety considerations, mode of action, delivery technique, and discussion of nursing implications is presented. Safety and effectiveness of vacuum extraction are supported by the results of a comparative study done at Mount Sinai Medical Center in which 256 vacuum extractions and 300 randomly selected forceps deliveries were performed. Indications for use, clinical status before application, maternal complications, and immediate neonatal complications are analyzed and discussed.

[External over-rotation of the head in the treatment of high longitudinal shoulder position]

The shoulder dystocias are an anomaly of shoulder presentation which render difficult or prevent complete extraction of the trunk following birth of the head. Acute hypoxia ensues, threatening the infant's life. Additionally, termination of delivery, which must be effected without delay and is surgically difficult, is frequently associated with often permanent damage to the upper limbs. Macrosomatia of the child and a vaginal-surgical delivery initiated before the preceding part has reached the pelvic floor increase the probability of high longitudinal shoulder position occurring. Early and forced application of Kristeller's method also encourages manifestation of the condition and simultaneous wedging of the shoulders in the pelvic inlet. Taking into account the inadequate shoulder rotation above the pelvic inlet, "external over-rotation of the head" is recommended as a treatment for high longitudinal shoulder position. The technique is described in detail. As soon as the condition appears likely to occur, the head is grasped in the hands (applied flat) and turned, in first position with the back of the head toward the right, in second position with the back of the head toward the left. This must be done early, i.e., if possible before the shoulders are finally locked in the pelvic inlet. Further expression of the trunk must not be assisted by Kristeller's method until high transverse position of the shoulders has been achieved. Clinicosurgical experience gathered so far and the early morbidity of the 24 children in whom high longitudinal shoulder position was overcome in this way justify the recommendation of "external over-rotation of the head" as an effective primary treatment method.

[Fetal monitoring sub partu in West Germany. II. Effect of clinic size and clinic type on monitoring practice]

Data from 690 clinics concerning obstetric management and intensive monitoring of the fetus sub partu were classified according to the type of hospital (e. g., municipal clinic, district hospital...) and the size of the hospital based on the number of births per year. On the basis of the annual number of births four groups (I-IV) were formed, each with 172 clinics. While the average number of surgical deliveries (cesarean, forceps, vacuum) is not related to the hospital (Table 3), it is related to the type of hospital (Table 6): the average number of cesarean deliveries is highest in university clinics (n = 24; 14.9%), and on average more forceps (6.5%) than vacuum extractions (5.7%) are performed. In all other hospitals vacuum extraction is clearly preferred (7-8%). The quotient Q of the annual number of births per CTG unit is not constant, but increases with the size of the clinic: In large hospitals (Group IV) significantly more births are monitored with a CTG unit (maximum 607, average 215), so that there is a numerical "monitoring deficit" as compared to smaller departments. The monitoring capability is numerically highest in the university clinics (Q = 147) and lowest in the academic teaching hospitals (Q = 192). The larger the clinic, the more frequently fetal blood is analyzed: the figure in large clinics is 40%. Small clinics are less familiar with this method (approx. 16%). The larger the clinic, the more often intrauterine catheters are used to measure labor; the figure rises from 7% to 29%.(ABSTRACT TRUNCATED AT 250 WORDS)

[Delivery planning and interdisciplinary management of large coccygeal teratomas]

Prenatal sonographic screening and a growing experience of examiners with regard to possible congenital malformations such as large coccygeal teratomas have induced the request for an early interdisciplinary consultation between obstetrician, human geneticist, paediatric surgeon, neonatologist and psychologist. It should aim at a careful information and counselling of the parents with regard to the mode of delivery and possibilities of operative management. The prerequisites for far sighted planning and performance of delivery are demonstrated by the example of large coccygeal teratomas. The availability of equipment, facilities and manpower at the time of delivery guarantees a course of delivery at reduced risk and is, together with the psychological guidance of the parents, a basic element of optimal care for the newborn.

Modified manual rotation in midpelvic delivery

A relatively atraumatic and simple technique for forceps rotation of the vertex is described for use when spontaneous rotation has failed to occur. The technique consists of applying the Laufe forceps as in a Scanzoni application to achieve maximum flexion of the vertex. The forceps blade is used only as an attachment for the finger rotation. No twisting of the forceps handle is required.

[Significance of trial vacuum extraction in the framework of obstetric surgery in vertex presentation]

On the basis of a clinical study of 76 infants born by trial vacuum extraction from the pelvic inlet, 57 infants were examined retrospectively with regard to early and late morbidity after "successful" trial vacuum extraction. In 34 cases surgery was indicated because of fetal distress; in 23 children the operation was performed because of a standstill at the pelvic inlet. The results were compared with a group of infants delivered by vacuum and forceps extraction from the centre of the pelvis (or the pelvic floor) or cesarean section in consequence of fetal distress. The results indicate the high risk for children born by trial vacuum extraction, especially in cases of fetal distress. In addition to statistically significant lower Apgar scores and a statistically significant higher acidosis morbidity (p less than 0.05) as compared to other obstetric operations, there is also a statistically significant greater number of "striking" and "injured" children as opposed to those delivered by vacuum or forceps extraction from the centre of the pelvis (or the pelvic floor) or by cesarean section in consequence of fetal distress. These neurological deviations represent primarily the static-motoric and speech development, and are analogous to late morbidity after births from breech presentation. The findings confirm the clinical impression that trial vacuum extraction-especially in cases of fetal distress at the pelvic inlet-represent an additional risk to the child. In such cases cesarean section is the only alternative method of delivery.

Early office termination of pregnancy by soft cannula vacuum aspiration

This report documents the results of an ongoing study of the first 454 consecutive outpatient abortions by menstrual extraction technique performed by the author over a span of 8 years. All patients had positive preevacuation pregnancy tests and the procedure was employed up to 9+ weeks from the first day of the last menstrual period. All procedures were carried out in an outpatient setting under local anesthesia. Pathologic evaluation revealed decidua and villi in all but 10 cases. Major complications were encountered in 2.6% of cases and in only two was laparotomy necessitated--one for a ruptured corpus luteum cyst and the other for an unruptured ectopic cornual pregnancy. The current application for the procedure is suggested by its technical simplicity and relative safety in population presenting for early termination of pregnancy.

Vacuum extraction: use in a small rural hospital

The effectiveness of vacuum extraction with the Silastic Obstetrical Vacuum Cup (SOVC), which has a soft, maleable cup, was assessed by two family physicians in a small rural hospital. Vacuum extraction was attempted in 35 of 231 deliveries over an 18-month period, with an overall success rate of 66%. The main indications for vacuum extraction were fetal distress, followed by a prolonged second stage of labour and malrotation of the occiput. The efficiency of the technique improved with experience. The effects of vacuum extraction on the fetus and mother compared favourably with those reported in the literature. After introduction of the SOVC, the rate of primary cesarean section for cephalopelvic disproportion declined, as did the rate of forceps delivery. Despite careful antenatal screening and referral, and the availability of alternatives, delivery by vacuum extraction with the SOVC was found to be a useful and effective adjunct to obstetric practice.

Rotational delivery of the fetus: Kielland's forceps and two other methods compared

A retrospective comparison was undertaken of 552 cases in which Kielland's forceps were used for rotation and delivery, 95 cases in which other forceps were used for rotation and delivery, and 160 cases in which manual rotation and forceps were used. There was no significant difference in maternal or fetal morbidity between the three groups, regardless of whether the indication for delivery was delay in the second stage of labour or fetal distress. When Kielland's forceps were used by junior staff, significantly more vaginal and cervical lacerations and primary postpartum haemorrhage occurred, but there was no increase in fetal morbidity.

[Obstetric spoons (author's transl)]

The article describes "obstetric spoons" which are easy to apply and which can be used as well as the forceps and the vacuum extractor for vaginal-operative termination of labor. These spoons offer the following advantages: They are an effective and relatively harmless instrument which can be applied rapidly and easily even by those who are less skilled. During extraction, the spoons are only slightly pressed onto the head of the child by the operator's hands; the additional pressure required is exercised by the soft parts of the mother. It is hardly critical if the spoons are not applied exactly in transverse diameter. If the traction force applied is too strong, they separate and slide over the head without exercising any further pressure. This counteracts any possible overforceful extraction. The spoons can also be applied simultaneously in combination with vacuum extraction and girdle expression, which renders even complicated vaginal surgical procedures from the mid-pelvic plane relatively harmless with regard to the strain exercised on the child.