Evaluating perinatal mortality rates: effects of referral and case mix.

OBJECTIVE--To evaluate perinatal mortality rates as a method of auditing obstetric and neonatal care after account had been taken of transfer between hospitals during pregnancy and case mix. DESIGN--Case-control study of perinatal deaths. SETTING--Leicestershire health district. SUBJECTS--1179 singleton perinatal deaths and their selected live born controls among 114,362 singleton births to women whose place of residence was Leicestershire during 1978-87. MAIN OUTCOME MEASURE--Crude perinatal mortality rates and rates adjusted for case mix. RESULTS--An estimated 11,701 of the 28,750 women booked for delivery in general practitioner maternity units were transferred to consultant units during their pregnancy. These 11,701 women had a high perinatal mortality rate (16.8/1000 deliveries). Perinatal mortality rates by place of booking showed little difference between general practitioner units (8.8/1000) and consultant units (9.3-11.7/1000). Perinatal mortality rates by place of delivery, however, showed substantial differences between general practitioner units (3.3/1000) and consultant units (9.4-12.6/1000) because of the selective referral of high risk women from general practitioner units to consultant units. Adjustment for risk factors made little difference to the rates except when the subset of deaths due to immaturity was adjusted for birth weight. CONCLUSION--Perinatal mortality rates should be adjusted for case mix and referral patterns to get a meaningful result. Even when this is done it is difficult to compare the effectiveness of hospital units with perinatal mortality rates because of the increasingly small subset of perinatal deaths that are amenable to medical intervention.     

Home births in England and Wales, 1979: perinatal mortality according to intended place of delivery.

A survey was carried out of all 8856 births occurring at home in England and Wales in 1979. Of these births, 67% had been booked for delivery at home, 21% had been booked for delivery in hospital, 3% had not been booked, and for 9% the intended place of delivery was unknown. The perinatal mortality varied almost 50-fold according to the intended place of delivery, ranging from 4.1/1000 births in those booked for delivery at home to 196.6/1000 unbooked births. Deliveries that occurred at home but had been booked for a hospital consultant unit were associated with a perinatal mortality of 67.5/1000. Births that had been booked for delivery at home included the smallest proportion of babies of low birth weight: 2.5% weighed 2500 g or less compared with 18% of those booked for consultant units and 29% of those not booked. Within these low birthweight groups there were noticeable differences in perinatal mortality; births booked to occur at home had the lowest mortality and unbooked births had the highest. Perinatal mortality among babies who weighed more than 2500 g was generally low irrespective of the intended place of delivery; the only exception was in babies whose delivery had not been booked. In all groups perinatal mortality was considerably higher in nulliparous than parous women. Women booking a delivery at home are clearly a selected group, and some may have been transferred to hospital during labour and were thus not included in the survey. Nevertheless, these data suggest that the perinatal mortality among births booked to occur at home is low, especially for parous women.     

Planned and unplanned deliveries at home: implications of a changing ratio.

The observation that perinatal mortality among babies delivered at home has tended to increase beyond that among babies delivered in consultant obstetric units has caused alarm and prompted recommendations that delivery at home should be further phased out. With data derived from the Cardiff Births Survey the possibility was investigated that this trend might reflect a changing ratio of planned to unplanned domiciliary births. At the beginning of the 1970s deliveries at home that were planned to be so outnumbered those that were not by nearly five to one. By 1979 unplanned deliveries at home outnumbered planned deliveries. The characteristics of the mothers, the health care they received, and the outcome of delivery differed strikingly between planned and unplanned deliveries at home. It is concluded, firstly, that every year the maternity services must try to meet the various needs of about 2000 women in England and Wales who give birth at home without planning to do so; and, secondly, that the heterogeneity of births at home and in hospital will continue to obstruct the search for unbiased estimates of the risks attributable to delivery in specialist obstetric units, general practitioner units, and at home.     

Audit of 26 years of obstetrics in general practice.

To assess the feasibility and quality of general practitioner obstetrics an audit of 1223 consecutive obstetric deliveries over 26 years was carried out with standard clinical records. The perinatal mortality of 9.0 per 1000 births was significantly better than the national average of about 19.0 per 1000 for the overall period. During the audit home deliveries virtually stopped. The proportion of consultant bookings and deliveries more than doubled because of more stringent booking arrangements despite relocation of the previously isolated general practitioner unit to beneath the consultant unit. Abnormal deliveries also rose significantly. A "steady state" was achieved during the final 11 years in which 73% of women booked to be delivered by their general practitioner, 64% were admitted to the general practitioner unit, and 54% were delivered by their general practitioner. Though this is enough to sustain obstetric experience, the proportion might safely be increased.     

Are isolated maternity units run by general practitioners dangerous?

A retrospective survey was carried out of women admitted in labour to an isolated maternity unit run by general practitioners in Penrith. In the five years 1980-4, 1267 women began labour in Penrith, of whom 1153 (91%) never required help from a consultant unit. Ninety required transfer during labour. Ten mothers and four neonates required transfer during the early puerperium, all to one receiving unit in Carlisle. There were six perinatal deaths during the five years; five occurred in babies delivered after transfer. The perinatal mortality was 4.7/1000. The low mortality, the low level of intervention, and the preference of women all support the retention of isolated units.     

Perinatal mortality and morbidity among babies delivered in water: surveillance study and postal survey

AimTo compare perinatal morbidity and mortality for babies delivered in water with rates for babies delivered conventionally (not in water).DesignSurveillance study (of all consultant paediatricians) and postal survey (of all NHS maternity units).SettingBritish Isles (surveillance study); England and Wales (postal survey).SubjectsBabies born in the British Isles between April 1994 and March 1996 who died perinatally or were admitted for special care within 48 hours of birth after delivery in water or after labour in water followed by conventional delivery (surveillance study); babies delivered in water in England and Wales in the same period (postal survey).Results4032 deliveries (0.6% of all deliveries) in England and Wales occurred in water. Perinatal mortality was 1.2/1000 (95% confidence interval 0.4 to 2.9) live births; 8.4/1000 (5.8 to 11.8) live births were admitted for special care. No deaths were directly attributable to delivery in water, but 2 admissions were for water aspiration. UK reports of mortality and special care admission rates for babies of women considered to be at low risk of complications during delivery who delivered conventionally ranged from 0.8/1000 (0.2 to 4.2) to 4.6/1000 (0.1 to 25) live births and from 9.2 (1.1 to 33) to 64/1000 (58 to 70) live births respectively. Compared with regional data for low risk, spontaneous, normal vaginal deliveries at term, the relative risk for perinatal mortality associated with delivery in water was 0.9 (99% confidence interval 0.2 to 3.6).ConclusionsPerinatal mortality is not substantially higher among babies delivered in water than among those born to low risk women who delivered conventionally. The data are compatible with a small increase or decrease in perinatal mortality for babies delivered in water.

Key messages

• Data on adverse effects of delivery in water have been limited
• Perinatal mortality and risk of admission for special care is similar for babies delivered in water and for low risk deliveries that do not take place in water
• The risk of perinatal mortality for babies delivered in water is similar to the risk for babies born by normal vaginal delivery to women at low risk of adverse outcome
• Delivery in water may have caused water aspiration in two babies and contributed to snapped umbilical cord in five

     

Outcome of pregnancies referred to a general practitioner maternity unit in a district hospital.

OBJECTIVE--To audit the outcome of pregnancies booked for confinement in a general practitioner maternity unit in a district general hospital. DESIGN--Retrospective review of case records. SETTING--General practitioner maternity unit in a district general hospital. PATIENTS--685 Women referred to a general practitioner unit in 1987. RESULTS--315 Nulliparous women and 330 multiparous women were booked for confinement; 202 women transferred to consultant care before delivery and a further 104 during labour or after delivery. Recognised risk factors, other than nulliparity, rarely predicted the need for transfer. Confinement in the general practitioner unit was associated with low intervention and good fetal outcomes. CONCLUSIONS--The general practitioner maternity unit provides a safe alternative for confinement in low risk pregnancies. High rates of transfer deny this facility to many women who desire confinement in a low technology environment.     

Contribution of isolated general practitioner maternity units.

A postal survey of isolated general practitioner maternity units in England and Wales showed that just under 4% of deliveries take place in them. Eight per cent of general practitioners are on the staffs, and in 87% of units midwives are integrated with the community midwifery service. Sixty two per cent of units have visiting consultant cover. Fifty seven per cent of patients are booked and delivered in the unit, 28% are booked and deliberately delivered elsewhere, 5% are transferred in the antenatal period, and 10% transferred as emergencies. The perinatal mortality rate for cases booked and delivered in the units is 1.1 per 1000. The number of emergency transfers was appreciably less for those units that were prepared to do their own operations. Thirty five per cent of these units are liable to be cut off in bad weather, and they will continue to fulfil an essential role in the midwifery services.     

Place of the General Practitioner in the Obstetric Service

A survey of perinatal mortality in Northern Ireland has shown that despite a progressive fall in the proportion of deliveries at home the perinatal mortality rate in domiciliary practice has risen in recent years. Overall, however, the perinatal mortality rate for all deliveries compares well with English figures. It seems that as the proportion of deliveries in hospital and general-practitioner obstetric unit rises a hard core of high risk patients is left who insist on delivery at home. Three prerequisites for good general-practice obstetrics are careful selection of cases, intelligent antenatal care, and close co-operation between the general practitioner and the consultant.     

General practitioner obstetrics in Bradford.

The standard of obstetrics care by general practitioners in Bradford was assessed by reviewing the case records of all women who in 1988 were booked for delivery under their general practitioner but subsequently required transfer to consultant care. A total of 5885 women were delivered in Bradford during 1988. Of 1289 booked under their general practitioner, 637 required transfer to consultant care. In 259 cases transfer occurred during labour; only 37 of these women were visited by their general practitioner. Many of the problems that precipitated transfer were predictable and some were considered preventable: 263 of the women transferred were considered unsuitable for booking by general practitioners. The perinatal mortality among women booked under their general practitioner was 10.1/1000 and the stillbirth rate 7.8/1000. These figures are high and suggest a need for tighter controls over the qualifications and experience of doctors participating in a fully integrated system of obstetric care.     

Management of labour in an isolated rural maternity hospital.

OBJECTIVES--To evaluate the use of a maternity unit run by general practitioners and midwives, describing the outcome of labour in an unselected group of women and quantifying the contribution made by general practitioners. DESIGN--Retrospective population based review of obstetric patients who had access to an isolated rural maternity unit. SETTING--Rural area 120 km from a consultant maternity unit. SUBJECTS--997 consecutive women delivered between January 1987 and May 1991. MAIN OUTCOME MEASURES--Mode of delivery and complications by place of booking and place of delivery; need for medical intervention and transfer. RESULTS--530 women (53%) were booked for delivery in the rural unit; this group had a caesarean section rate of 3.8% and an unplanned transfer rate of 12.8% to the consultant unit in labour. Of the 462 who delivered in the low risk unit, 25 (5%) required a forceps delivery; postnatal complications requiring emergency medical support occurred in a further 33 (7%). CONCLUSIONS--Risk characterisation is possible, but medical support from general practitioners and obstetricians is required in almost a third of women at low risk for complications of delivery. Results of this study support the team approach to obstetric management but not the move towards isolated units without organised medical support.     

Use by general practitioners of obstetric beds in a consultant unit: a further report.

Of 1,700 women booked for delivery by general practitioner obstetricians in a consultant unit, 1,399 had uncomplicated deliveries and the co-operation between practitioner and consultant was an obvious advantage for the 257 who were transferred completely to consultant care during pregnancy, labour, or puerperium. The scheme, which started in 1964, has enabled general practitioners to continue to give complete obstetric care to their patients. The number of participating practitioners has, however, declined from 80 to 16 indicating that many preferred to concentrate on antenatal work.     

Home versus hospital deliveries: follow up study of matched pairs for procedures and outcome. Zurich Study Team.

OBJECTIVE: To assess procedures and outcomes in deliveries planned at home versus those planned in hospital among women choosing the place of delivery. DESIGN: Follow up study of matched pairs. SETTING: Antenatal clinics and reference hospitals in Zurich between 1989 and 1992. SUBJECTS: 489 women opting for home delivery and 385 opting for hospital delivery; the women comprised all those attending members of the study team for antenatal care and those attending the reference hospital for antenatal care who could be matched with the women planning home confinement. MAIN OUTCOME MEASURES: Need for medication and incidence of interventions during delivery (caesarean section, forceps, vacuum extraction, episiotomy), duration of labour, occurrence of severe perineal lesions, maternal blood loss, and perinatal morbidity and death. RESULTS: All women were followed up from their first antenatal visit till three months after delivery. Referrals during pregnancy (n = 37) and labour (70), changes of mind (15 home to hospital, eight hospital to home), and 17 miscarriages resulted in 369 births occurring at home and 486 in hospital. During delivery the home birth group needed significantly less medication and fewer interventions whereas no differences were found in durations of labour, occurrence of severe perineal lesions, and maternal blood loss. Perinatal death was recorded in one planned hospital delivery and one planned home delivery (overall perinatal mortality 2.3/1000). There was no difference between home and hospital delivered babies in birth weight, gestational age, or clinical condition. Apgar scores were slightly higher and umbilical cord pH lower in home births, but these differences may have been due to differences in clamping and the time of transportation. CONCLUSION: Healthy low risk women who wish to deliver at home have no increased risk either to themselves or to their babies.     

Confidential paediatric inquiry into neonatal deaths in Wessex, 1981 and 1982.

From 1 January 1981 to 31 December 1982, 66 256 births and 386 neonatal deaths were recorded in the Wessex Regional Health Authority, giving a neonatal mortality of 5.8/1000 live births. An experienced consultant paediatrician undertook a confidential inquiry into each death shortly after it had been reported. One hundred and forty four deaths (37%) were found to be due to lethal or severe malformations, an incidence of 2.2/1000 births. Of the 242 normally formed infants, 111 (46%) died within 24 hours of birth. Seventy seven (32%) weighed over 2500 g at birth. Factors operating before delivery accounted for 104 (43%) of the deaths of normally formed infants. The commonest factors were short gestation and low birth weight, and intrauterine hypoxia and birth injury. Factors after delivery accounted for 81 deaths (33%), the commonest being infections and sudden infant deaths. In the remaining 57 deaths (24%) it seemed that a combination of factors before and after birth had led to the death. Factors before birth thus played a part in two thirds of all deaths. Possible adverse factors in medical care were sought in 154 potentially viable babies and were identified in 38--that is, 10% of all neonatal deaths. Better provision and training of district staff in immediate care at birth would achieve more in lowering neonatal mortality in Wessex than the setting up of a regional unit specializing in advanced neonatal intensive care. Moreover, the greatest scope for improving the outcome of childbirth in Wessex would be offered if there were further advances in obstetric rather than neonatal care.     

Changing pattern in a general practitioner obstetric unit.

Over the past nine years in Watford the proportion of hospital confinements has increased and domiciliary confinements have almost ceased. The proportion of patients originally booked into the general practitioner obstetric unit and subsequently transferred to the consultant unit has increased. Most patients are transferred during pregnancy, and the numbers transferred in labour are decreasing. The proportion of GPs attending their patients for delivery is low: local practitioners appear to be prepared for the consultant unit to supervise delivery with the practitioner co-operating in antenatal and postnatal care and family planning. There seems little doubt that the success of GP units depends on the enthusiasm and interest of individual practitioners.     

Attitudes to viability of preterm infants and their effect on figures for perinatal mortality.

OBJECTIVE--To examine how local attitudes to management of extreme preterm labour can influence data on perinatal mortality. DESIGN--One year prospective study in a geographically defined population. SETTING--The 17 perinatal units of Trent region. PATIENTS--All preterm infants of less than or equal to 32 weeks'' gestation in the Trent region. INTERVENTIONS--Infants who had been considered viable at birth were referred for intensive care; those who had been considered non-viable received terminal care. MAIN OUTCOME MEASURES--Whether each infant was born alive, dead, or alive but considered non-viable. RESULTS--Large differences were observed among units in the rates of delivery of infants of less than or equal to 27 weeks'' gestation (rates varied from 7.2 to 0 per 1000 births). These differences were not present in the data relating to infants of between 28 and 32 weeks'' gestation. The variation seemed to result from different approaches to the management of extreme preterm labour--that is, whether management took place in a labour ward or a gynaecology ward. CONCLUSIONS--Place of delivery of premature babies (less than or equal to 27 weeks'' gestation) may influence classification and hence figures for perinatal mortality. In addition, the fact that the onus of judgment regarding viability and classification is often placed on relatively junior staff might also affect the figures for perinatal mortality. The introduction of a standard recording system for all infants greater than 500 g would be advantageous.     

Collaborative survey of perinatal loss in planned and unplanned home births. Northern Region Perinatal Mortality Survey Coordinating Group.

OBJECTIVE: To document the outcome of planned and unplanned births outside hospital. DESIGN: Confidential review of every pregnancy ending in stillbirth or neonatal death in which plans had been made for home delivery, irrespective of where delivery eventually occurred. The review was part of a sustained collaborative survey of all perinatal deaths. SETTING: Northern Regional Health Authority area. SUBJECTS: All 558,691 registered births to women normally resident in the former Northern Regional Health Authority area during 1981-94. MAIN OUTCOME MEASURE: Perinatal death. RESULTS: The estimated perinatal mortality during 1981-94 among women booked for a home birth was 14 deaths in 2888 births. This was less than half that among all women in the region. Only three of the 14 women delivered outside hospital. Independent review suggested that two of the 14 deaths might have been averted by different management. Both births occurred in hospital, and in only one was management before admission of the mother judged inappropriate. Perinatal loss to the 64 women who booked for hospital delivery but delivered outside and to the 67 women who delivered outside hospital without ever making arrangements to receive professional care during labour accounted for the high perinatal mortality (134 deaths in 3466 deliveries) among all births outside hospital. CONCLUSIONS: The perinatal hazard associated with planned home birth in the few women who exercised this option (< 1%) was low and mostly unavoidable. Health authorities purchasing maternity care need to address the much greater hazard associated with unplanned delivery outside hospital.     

Midwife managed delivery unit: a randomised controlled comparison with consultant led care.

OBJECTIVE--To examine whether intrapartum care and delivery of low risk women in a midwife managed delivery unit differs from that in a consultant led labour ward. DESIGN--Pragmatic randomised controlled trial. Subjects were randomised in a 2:1 ratio between the midwives unit and the labour ward. SETTING--Aberdeen Maternity Hospital, Grampian. SUBJECTS--2844 low risk women, as defined by existing booking criteria for general practitioner units in Grampian. 1900 women were randomised to the midwives unit and 944 to the labour ward. MAIN OUTCOME MEASURES--Maternal and perinatal morbidity. RESULTS--Of the women randomised to the midwives unit, 647 (34%) were transferred to the labour ward antepartum, 303 (16%) were transferred intrapartum, and 80 (4%) were lost to follow up. 870 women (46%) were delivered in the midwives unit. Primigravid women (255/596, 43%) were significantly more likely to be transferred intrapartum than multi-gravid women (48/577, 8%). Significant differences between the midwives unit and labour ward were found in monitoring, fetal distress, analgesia, mobility, and use of episiotomy. There were no significant differences in mode of delivery or fetal outcome. CONCLUSIONS--Midwife managed intrapartum care for low risk women results in more mobility and less intervention with no increase in neonatal morbidity. However, the high rate of transfer shows that antenatal criteria are unable to determine who will remain at low risk throughout pregnancy and labour.     

Perinatal deaths: analysis by clinical cause to assess value of induction of labour.

Over the 10 years 1966-75 the rate of induction of labour in the Glasgow Royal Maternity Hospital has increased from 16-3% of all births. During the same period perinatal mortality fell from 33 to 22 per 1000, mainly because of significantly fewer deaths due to antepartum haemorrhage; trauma; maternal diseases; and unknown causes in mature babies. The reduction in the number of deaths of unknown causes in mature fetuses was achieved by preventing deaths occurring after 40 weeks and was recorded in all age and parity groups. The results suggested that increased use of induction of labour has contributed to the improved perinatal mortality rate.     

Perinatal mortality and morbidity associated with eclampsia.

Out of all the women who were delivered in Cardiff maternity units during 1965-74, 43 developed eclampsia, an incidence of 72/100 000 deliveries. The incidence in residents of Cardiff was 53/100 000 deliveries. None of the mothers with eclampsia died, but 10 of the 47 babies were lost, all but one having been born to women with antepartum eclampsia. The perinatal deaths were mainly associated with chronic placental insufficiency and preterm delivery. The extent to which the wide range of complex drug regimens used influenced perinatal outcome is not clear, although polypharmacy should be avoided. Because eclampsia is rare we advocate that its management should be planned and rehearsed and that a simple, standardised treatment regimen should be used. Failing placental function may be detected by monitoring fetal growth by ultrasound.