Archiuvs of Disease in Chidhood 1996;75:F97-FI02

Outcome in low risk pregnancies

Renu Arya, Tim Pethen, Richard B Johanson, S Andrew Spencer

AbstractAins-To determine the obstetric andneonatal outcomes of a cohort ofvery lowrisk pregnancies in hospital, that would besuitable for home delivery.Methods-A retrospective analysis was

undertaken of computerised records cov-

ering five years from July 1988 to August1993 of 32424 pregnant women who deliv-ered at the North Staffordshire MaternityHospital, Stoke on Trent, during thatperiod.Results-Of 32424 deliveries, only 1314(4%) fulfilled our criteria for being lowrisk. Sixty seven (5.1%) of the low riskgroup had an operative delivery, withCaesarean section accounting for 32(2.4%) cases, 16 (23.90!%) babies were

resuscitated and three were intubated. Anormal vaginal delivery occurred in 1245women, but a paediatrician attended 122births (9.22%), assisted ventilation was

provided in 65 cases (5.2%), and fivebabies were intubated (0.4%). Fourteenbabies in total were admitted to theneonatal unit and one died.Conclusions-These results suggest thatat least 5% ofwomen suitable for deliveryat home will require transfer in labour.Midwives attending home births must beskilled in bag and mask resuscitation as

only rarely will an urgent intubation berequired. The British Paediatric Associa-tion Working Party report on neonatalresuscitation suggests a need for resusci-tation in only 0.2% of low risk deliveries:but these findings suggest that the need isgreater.(Arch Dis Child 1996;75:F97-F102)

Keywords: low risk deliveries, home birth, neonatalresuscitation

Department ofPaediatricsNorth StaffordshireHospital andUniversity ofKeeleStoke on TrentR AryaS Spencer

Department ofObstetricsT PethenRichard B Johanson

Correspondence to:Dr Arya,Department of Paediatrics,North Staffordshire Hospitaland University of Keele,Stoke on Trent, StaffordshireST4 6QG.

Accepted 30 April 1996

The Department of Health report ChangingChildbirth: the Report of the Expert MaternityGroup recommends that women should havean informed choice with regard to the place ofbirth.' This includes the opportunity for a

planned home birth, an option 1 in 8 Britishwomen would be interested in pursuing.2 Thereport states that when evaluating the risk of anunexpected emergency at home, this should bebalanced against the evidence from publishedstudies which show higher obstetric interven-tion rates in hospital.' These studies, how-ever, have largely concentrated on the obstetricaspects of the pregnancy and include littleanalysis of the role of the paediatrician at thedelivery. Indeed, there is a lack of publisheddata available on the neonatal outcome of low

risk pregnancies in this country.'0 This infor-mation is required in planning a service that islikely to include a much larger proportion ofhome deliveries.At the North Staffordshire Maternity Hospi-

tal computerised records have been kept of alldeliveries since 1988. This database containsinformation about complications arising dur-ing pregnancy and outcomes for both motherand child, including details of neonatal resusci-tation. Data are collected for the deliveriesbooked for both the consultant and the GPunits. There are over 6000 deliveries a year andreferrals are accepted from other hospitals inthe region for high risk pregnancies. This com-prehensive database provided an opportunityto perform a retrospective analysis of theoutcome of a very large number of pregnan-cies. The aims of this study were to determi-ne:(i) the proportion of the study populationfalling into the low risk category usingpredefined criteria; (ii) the rate of obstetricintervention required in the low risk group;and (iii) the incidence of paediatric interven-tion, resuscitation, and neonatal outcome inthese remaining low risk deliveries.

MethodsThe study was based on a population ofwomen booked at the North StaffordshireMaternity Hospital in the years from July 1988to August 1993. Mothers booked into both theconsultant and GP units were included.Patients who delivered but were not booked atthe hospital were excluded.To select our low risk population, we

excluded those pregnancies associated withany recognised risk factors 1112 either at thetime of booking or developing during the preg-nancy (table 1). Those selected were women ingood health with at least one previous unevent-ful pregnancy. All these women would havebeen suitable candidates for home delivery." 14.Information regarding birthweight, gestationalage, sex and Apgar scores was collected.

Patients who had an instrumental deliverywere identified. The reasons for interventionwere analysed. The group was divided intothose performed urgently to reduce the risk tothe fetus and those performed for otherreasons. The requirement for paediatric sup-port or resuscitation was considered separatelyin this group as it is likely that these patientswould have been transferred to hospital beforedelivery.

In the normal vaginal delivery group analysisof the incidence of complications, paediatricinvolvement, and the numbers of infants resus-citated was performed. Fetal distress wasdefined as an abnormal fetal heart rate either

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Age < 17 or > 35, height < 155 cm, unsupportedmotherPrimigravida or parity > 3; previous Caesarean section;previous termination of pregnancy > 12 weeks; recurrentabortions or previous spontaneous abortions; involuntaryinfertility; previous postpartum haemorrhage or bloodtransfusion; third degree tear or retained placenta;myomectomy or previous hydatidiform molePrevious babies < 2500 g, or large for dates ( > 4500 g),premature infants < 37 weeks, previous stillbirth orneonatal deathDiabetes, hypertension, chest disease, heart disease,epilepsy, immune thrombocytopenia, myasthenia gravis,systemic lupus erythematosus, renal disease, thrombosis orhepatitisTwin or breech presentation, preterm delivery < 37weeks, high serum afetoprotein, amniocentesis, if labourwas induced

on Pinnard auscultation or on cardiotocograph(CTG), with type 1 and/or 2 dips, bradycardiaor fetal tachycardia, or an abnormal fetal scalppH ( < 7.2). The presence ofmeconium in theliquor with or without an abnormal cardio-tocogram was considered a separate category,but the grade of meconium was not qualified.Failure to progress was defined as a failure ofthe cervix to dilate at a rate of 1 cm/hour over afour hour period of observation despite goodcontractions. Where more than one complica-tion was present, the patient was allocated tothe category which was considered to be themost important in that patient's care.The resuscitation received was classified into

four categories: none/suction only; facial oxy-gen, bag, and mask ventilation; and intubationwith or without cardiac massage. Resuscitationperformed by midwives was noted. The casenotes were reviewed in all cases where intuba-tion took place to obtain as much informationas possible about the need for intubation. Thecase notes of a sample of babies who receivedbag and mask ventilation were also comparedwith the database to check the level ofvalidation.Outcome with regard to deaths and admis-

sion to the neonatal intensive care unit(NICU) was assessed for all low risk deliveries.

ResultsDuring the study period there were 32424deliveries at the hospital. Of these, only 1312(4.0%) fulfilled the criteria for being extremelylow risk.

Six hundred and sixty three mothers(50.5%) had been booked for delivery in theGP unit but 132 (10.1%) were transferred tothe consultant unit due to a problem arisingduring labour. The other 768 mothers deliv-ered as booked in the consultant unit. Twelvewomen delivered unexpectedly either at homeor before arrival at hospital.The mean gestational age of the infants was

40 weeks (range 37 to 47 weeks) and therewere similar numbers ofboys (n = 635) to girls(n = 677). The mean birthweight was 3500 g,

all the babies apart from two being within therange 2000-5000 g. One baby was small fordates (1760 g) and the other, large for dates(5080 g), and neither had been diagnosedbefore delivery. Despite being so large, the5080 g baby did not have any problems and

Table 2 Reasonsfor assisted delivery

Complication Assisted delivery (n=67) (%)

Fetal distress 23 (34.3)Failure to progress 18 (26.9) (5)*Abnormal presentation I 1 (16.4) (5)*Meconium stained liquor 9 (13.4)Cord prolapse 5 (7.5) (2)*Other reason 1 (1.5)

* These figures refer to the deliveries where there was alsoassociated fetal distress

did not require any resuscitation. The Apgarscores were equal to or greater than 7 at 1minute in 1231 babies (93.8%), but 75 babies(5.7%) had a score of less than 7, and of these,13 had a score of less than 4. The 5 minuteApgar score was equal to or greater than 7 in1305 babies (99.5%). However, five babies stillhad a low score after 5 minutes and one did nothave a score recorded as he was beingventilated and receiving cardiac massage at thetime.

ASSISTED DELIVERIESObstetric intervention was required in 67(5.1%)deliveries. Of these, 32 women had anemergency Caesarean section (2.4%), 23 had aventouse extraction (1.8%), and 10 had aforceps delivery (0.8%). Two women had abreech delivery as the breech presentation wasnot diagnosed until they were in labour. Thereasons for intervention are shown in table 2.

In 44 of these deliveries there were also signsof fetal distress. Furthermore, in the groupsthat required intervention for prolonged labouror abnormal presentation three infants re-ceived bag and mask ventilation and one infantwas intubated despite the absence of fetaldistress. Only one of the five infants with cordprolapse required intubation, and one receivedbag and mask ventilation. No morbidity wasexperienced by this group. Nevertheless, adelay in delivery could have had an adverseeffect on outcome. In total 47 (70%) of thisgroup (3.6% of the entire low risk group) mayhave been at greater risk for this reason.With regard to outcome, five babies were

admitted to the NICU. Three required ventila-tion in association with meconium stainedliquor and all three went on to develop convul-sions. One ofthe three died with severe hypoxicischaemic encephalopathy. The remaining twonon-ventilated babies showed signs of mildasphyxial encephalopathy but subsequentlymade a good recovery.

NORMAL VAGINAL DELIVERIESThere were 1245 normal vaginal deliveries(94.9%). In 185 (14.8%) of these, there was acomplication. The prevalence of each compli-cation is shown in table 3. A paediatrician wascalled to 122 deliveries (9.8%).Although 531 women delivered in the GP

unit (40% of the total low risk group), therewas a complication in 31 deliveries (5.4%) and21 babies received bag and mask ventilation orwere intubated. There were nine deliverieswith meconium stained liquor and despitebeing in hospital, there was not enough timebefore delivery for the women to be transferredto the consultant unit.

Table 1 Risk factors excludedfrom population studied

Personal characteristics

Obstetric history

Previous babies

Maternal history, past or current

Current pregnancy

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Table 3 Complications arising during labour or afterdelivery

Normal vaginal ddiveryComplication (n=1245)(4%)

Meconium stained liquor 101 (8.1)Failure to establish 37 (3.0)

respirationsFetal distress 30 (2.4)Cord around neck 7 (0.6)Shoulder dystocia 3 (0.2)Other reason 7 (0.6)

Table 4 Level of resuscitation required after normalvaginal delivery

Normal vaginal deliveryLevel of resuscitaion required (n=1245) (%/6)

None/suction only 1029 (82.7)Facial oxygen 151 (12.1)Bag and mask 60 (4.8)Intubation 5 (0.4)Intubation plus cardiac 1 (0.1)massage

The level of resuscitation provided is shownin table 4. Assisted ventilation was given to 65babies (5.2%). Of these, five were intubatedand one also required cardiac massage. Thereasons for assisted ventilation were recordedas failure to establish respirations despitesimple measures such as suction and stimula-tion (n = 32), meconium stained liquor (n= 14), fetal distress (n = 9), cord round theneck (n = 7), and shoulder dystocia (n=3).

In 35 (53.8%) cases assisted ventilation wascarried out by the paediatrician including allthe intubations, whilst the other 30 were man-

aged by midwives.In this group of 65, 47 mothers required

either no analgesia or Entonox alone. Sixmothers had an epidural and 12 mothers hadpethidine before the delivery. Eleven of thebabies received naloxone at the time of resusci-tation.

INTUBATED BABIESFive babies from the normal vaginal deliverygroup were intubated. The case histories forthe babies are as follows.The first baby had a falling heart rate just

before delivery. He was floppy and apnoeicafter birth, but had a good heart rate. He was

intubated and received intermittent positivepressure ventilation for 4 minutes because offailure to respond to bag and mask ventilationfor 3 minutes. He established regular respira-tions at 7 minutes and was extubated. Apgarscores were 4 and 8 at 1 and 5 minutes, respec-tively. His birth weight was 3.75 kg.

In the second case there was fresh meco-

nium stained liquor at delivery. The baby was

given suction and there was no meconiumbelow the cords. He was intubated andventilated with intermittent positive pressureventilation for 6 minutes because he failed toestablish respirations. Apgar scores were 7 and9 at 1 and 5 minutes. His birth weight was

3.33 kg.The third baby had meconium stained

liquor and shoulder dystocia at delivery. Hehad irregular respirations and was intubatedand received intermittent positive pressure

ventilation for over 6 minutes. There was nomeconium below the cords. Apgar scores were6 and 8 at 1 and 5 minutes, respectively. Hisbirth weight was 4.24 kg.

In the fourth case meconium stained liquorwas discovered on artificial rupture of mem-branes 10 minutes before delivery which wasprecipitous in the second stage. The cord wastight around the neck. The baby initially had agood heart rate but poor respiratory effort.Two minutes after delivery, the heart rate fell to60 beats per minute; tone, colour and respira-tory effort were poor. The infant was slow torespond to bag and mask ventilation and wasintubated for 1 minute with a good response.There was no meconium below the cords.Apgar scores were 4 and 10 at 1 and 5 minutes.His birthweight was 3.8 kg.

In the fifth case there was meconium stainedliquor at delivery, and as the head wasdelivered the cord was tight around the neck.The cord was cut and clamped but there wasdifficulty in delivering the body due toshoulder dystocia. The baby was born in poorcondition and was intubated from birth andreceived cardiac massage for 6 minutes. He wastransferred, ventilated, to the NICU andsubsequently developed hypoxic ischaemicencephalopathy and convulsions. He was extu-bated after 48 hours and was discharged homewith a course of anticonvulsants. Apgar scoreat 1 minute was 2; the 5 minute Apgar scorewas not recorded. His birthweight was 4.1 1 kg.

ADMISSIONS TO NEONATAL INTENSIVE CARENine babies from the normal vaginal deliverygroup were admitted to the NICU. Only one ofthe babies who had been intubated at birth wasadmitted. One baby was unexpectedly smallfor dates (1760 g), three had meconiumaspiration syndrome-one in association withshoulder dystocia. A further two babies hadshoulder dystocia and showed signs of birthasphyxia. Three other babies were slow todevelop spontaneous respirations. All of theseinfants recovered, although one of the babieswith shoulder dystocia and meconium aspira-tion was ventilated. He subsequently devel-oped moderate hypoxic ischaemic encephal-opathy. He was started on anticonvulsants andcontinued taking them once at home. Anotherinfant had a diaphragmatic hernia and wastransferred, ventilated, to a surgical unit.

DiscussionIn assessing the potential risks to infants of ahome delivery ideally data on low risk deliver-ies conducted in the home are needed. Withthe drive in the 1970 and 1980s 15-7 for hospi-tal deliveries, there are currently few homedeliveries to study. In the North Staffordshireregion, until now, only 16 to 20 women a yearhave elected to have their babies at home. Theoutcome of low risk pregnancies may beaffected by the socioeconomic status of thepopulation and therefore we wished to obtaininformation relevant to our own population.The only way to achieve this was to study hos-pital based deliveries, although about half of

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these were planned for the GP unit whereobstetric intervention is kept to a minimumunless complications arise.

In selecting our low risk population weexcluded patients on the basis of known riskfactors which only left 4%. There are, ofcourse, problems in retrospectively analysingcomputerised data. For example, we were notable to differentiate mild from severe asthmaand so all patients classified as having chronicchest problems were excluded from the lowrisk group. In practice the attending physicianwould use clinical judgment to determine theimportance of any given risk factor in an indi-vidual patient and thus greatly refine the selec-tion criteria. Nevertheless, in this study we areconfident that all significant risks were ex-cluded, leading to the selection of the lowestrisk population possible. Furthermore, the useof risk factor analysis is an imperfect indicatorfor predicting whether a delivery would be lowor high risk, but this method is currently in usein clinical practice in many booking clinics.The use of these risk factors may place a lowrisk woman into a high risk category, but isunlikely to miss any with clinically relevantobstetric illness.'o20 Accepting that transfer ofpatients in labour will be required for assisteddelivery, the numbers of patients actuallydelivering at home would be further reduced to3.8%. Clearly if a target of 20-25% homedelivery rate is anticipated then further workwill be required to determine which of the riskfactors is most significant and which should bedropped.We were concerned that over 5% of this

group of patients with no known risk factorsdid not have a normal vaginal delivery. It mightbe argued that this figure would be much lowerhad the patients actually delivered at home.Nevertheless, this level of support/need fortransfer and its subsequent consequencesshould be accounted for at the planning stageofcommunity services until it is confirmed thatthis is an overestimation. In providing in-formed choice any additional risk to a dis-tressed infant arising from a delay in deliveryshould be discussed with the mother.Over 5% of those infants who might well

have been considered suitable for homebirthreceived resuscitation at a level which includedassisted ventilation. In many of these casescomplications could not have been anticipateduntil the time of delivery or shortly before. Thepresence of meconium stained liquor is onereason for prompt transfer to hospital but thiscan present late on in labour and there may notbe time for the transfer to take place before thebaby is delivered. Indeed, in this study, ninebabies with meconium stained liquor deliveredin the GP unit as there was not enough timebefore delivery, even in hospital, to be trans-ferred down to the consultant unit. A paedia-trician was called to attend 9.8% of normaldeliveries and although this may be a reflectionof local guidelines, the reason for attendance inthis low risk group was for anticipatedproblems with the baby, such as meconiumstained liquor or failure to establish respira-tions.

Only five infants were actually intubated,one patient for each year of study. The rate ofintubation varies among hospitals.21 The skillof the resuscitator may influence intubationrates, with skilled operators providing a muchlower level. Skilled operators may be better atselecting patients for intubation, or theyobviate the need because their skills in manag-ing the pre-intubation resuscitation are moreeffective. It is clear that midwives or the persontaking responsibility for the delivery will needto develop these skills and occasionally therewill be an unexpected need for intubation. Itmay be difficult for personnel to acquire orretain skills in intubation when the procedureis so rarely called for in this group. Perhaps thisproblem could be overcome if staff rotatethrough high risk units and are given responsi-bility for resuscitation in this group as well. Itmay be unrealistic to expect communitymidwives/GPs to intubate, and a paramedicflying squad may be an alternative. Theincreased risk of an adverse outcome from anydelay in resuscitation should be discussed withparents considering a home delivery.The BPA Working Party Report cites a need

for neonatal resuscitation in only 0.2% of lowrisk births.22 This figure was based on a Swed-ish study by Palme-Kilander." In our study5.2% of the babies born by normal vaginaldelivery received assisted ventilation, althoughonly five (0.4%) were intubated. The studiesare not directly comparable. In the Swedishstudy the parameters for identifying the lowrisk population were not defined and the needfor resuscitation was assessed on the basis oflow Apgar scores. The North Staffordshirestudy is more representative of the British situ-ation and should serve to inform thedebate.2""

1 Department of Health. Changing childbirth: the report of theexpert maternity group. (Cumberlege report) London:HMSO, 1993.

2 MORI. Changing childbirth. London: HMSO, 1993.3 Shearer JML. A five-year prospective survey of risk ofbook-

ing for a home birth. BMJ 1985; 291: 1478-80.4 Klein M, Lloyd I, Redman C, Bull M, Turnbull AC. A com-

parison of low-risk pregant women booked for delivery intwo systems ofcare. BrJ Obstet Gynaecol 1983; 90: 118-22.

5 Ford C, Iliffe S, Franklin 0. Outcome of planned homebirths in an inner city practice. BMJ 1991; 303: 1517-9.

6 Duran AM. The safety ofhome birth: the farm study. Am JPublic Health 1992; 82: 450-3.

7 MacVicar J, Dobbie G, Owen-Johnstone L, Jagger C, Hop-kins M, Kennedy J. Simulated home delivery in hospital: arandomised controiled trial. Br _J Obstet Gynaecol 1993;100: 316-23.

8 Albers LL, Katz VL. Birth setting for low-risk pregnancies:an analysis of the current literature. Jf Nurse Midwifery1991; 36: 215-20.

9 Eskes TK. Home deliveries in The Netherlands - perinatalmortality and morbidity. Int J Gysaecol Obstet 1992; 38:161-9.

10 Dixon EA. Review of maternity patients suitable for homedelivery. BMJ 1982; 284: 1753-5.

11 Buder NR, Bonham DG. Priata mortality. The first reporton the 1958 per d mortality survy. Edinburgh and Lon-don: E & S Uvingstone, 1963.

12 Ministry ofHealth. Report on confidentia enquiries into mater-nal deaths in England and Walks 1958-60. Reports on publchealth and medical su Noa 108. London: HMSO, 1963.

13 Van Alten D, Bskes M, Treffers PE. Midwifery in the Neth-erlands. The Wormerveer study; selection, mode of deliv-ery, perinatal mortality and infant morbidity. BrJ ObstetGynaecol 1989; 96; 96: 656-62.

14 Oppenheimer C.O nising midwifery care in the Nether-lands. BMg 1993; 307: 1400-2.

15 Social Services Committee (Chairman, R Short). Perinatand neonatl mortaliy. Second Report from the Social Ser-vices Committee, Session 1979-80, Vol 1, Cmnd 663-1.London: HMSO,1980.

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16 Standing Maternity and Midwifery Advisory Committee(Chairman, J Peel). Domiciliary midwifery and maternity bedneeds. London: HMSO, 1970.

17 Campbell R, Macfarlane AJ. Where to be born? 7he debate andthe evdence. 2nd edn. Oxford: National Perinatal Epidemi-ology Unit, 1987.

18 Cole SK, Mcllwaine GM. The use of risk factors in predict-ing possible consequences of changing patterns of care inpregnancy. In: Chamberlain G, Patel N, eds. 7he future ofmaternity services. London: Royal College of Gynaecolo-gists, 1994: 65-72.

19 Chard T, Learmont J, Carroll S, Hudson C, Lloyd DS,Sloan D. Evaluation of a fetal risk-scoring system. Am JPerinatol 1992; 9; 388-93.

20 Bull MJV. Selection ofwomen for community obstetric care.In: Chamberlain G, Patel N, eds. The future of matrnityservices. London: Royal College of Gynaecologists, 1994:73-81.

21 Scottish Health Service Common Services Agency. Hospitaland Health Board comparisons in obstetrics 1988-1990. Edin-burgh: Information & Statistics Division, 1992:57.

22 British Paediatric Association. Neonatal _susiation Reportofa BPA Working Party. London: BPA, 1993.

23 Palme-Kilander C. Methods of resuscitation in low-Apgarscore newborn infants - a national survey. Acta Paediatr1992; 81: 739-44.

24 Sackin P. Maternity services. BMJ 1992; 304: 1056-7.25 Balen A. Maternity services. BMJ 1992; 304: 1057.26 McGarry J. Maternity services. BMJ 1992; 304:1057.27 Fleissig A, Cartwright A. Women's preference for place of

birth. BMJ 1992; 305: 476.28 Newburn M. Women's preference for place of birth. BM3'

1992; 305:476.29 Glasier A, Anderson F. Women's preference for place of

birth. BMJ 1992; 305: 476.30 Johnson M, Haddad S, Smith J, Wong A. Women prefer

hospital births. BMJ 1992; 305: 255.31 Sullivan C, Leslie A, Stephenson T. Emergency transport

for neonates after home deliveries. BMJ 1994; 309: 742.32 Young G, Drife J. Home or hospital birth? Practoner 1992;

236:672-4.33 Kargar I. Every woman's rights. Nursing Times 1992; 88: 66.34 Young GL. Place of birth. In: Chamberlain G, Patel N, eds.

The future of maernity services. London: Royal College ofGynaecologists, 1994: 53-60.

35 McClure BG. The role of the paediatrician. In: Chamber-lain G, Patel N, eds. The future of maternity services.London: Royal College of Gynaecologists, 1994: 240-3.

CommentaryIn England and Wales home births are stilluncommon, but their numbers are risingsteadily. After falling to an all time low of0.89% in 1987, the percentage of maternitiesoccurring at home reached 1.94 % in 1995.'Despite this doubling, the numbers of homebirths in most districts are still small, making itdifficult to monitor trends and predict theimplications for services. Data are also in shortsupply at any level, apart from a survey ofplanned and actual home births in the North-ern Region in 19932 and the National BirthdayTrust's as yet unpublished survey of plannedhome births in 1994.The authors' ingenious response to the lack

of data for their own population was aretrospective analysis of computerised dataabout selected women who actually experi-enced hospital care.They interpret this cau-tiously, conscious that benefits and hazards ofhospital care are different from those associ-ated with home delivery, and that the outcomemight have been different if the same group ofwomen had planned to deliver at home. Howdoes their analysis help us, what questions doesit raise, and what further information isneeded?The authors were concerned to find that 5%

of women in their extremely low risk groupmight have required transfer in labour and feltthat this was a cause for concern. From astatistical perspective, however, their approachcould be viewed as a screening procedure, witha relatively low rate offalse negative results andthus a high sensitivity of 95%. Although itidentified a group of women in which the rate

of complications is low, it cannot by its verynature predict which individual women in thegroup will experience these complications.

People faced with the problems of planningservices and providing care for women whoneed to transfer to hospital in labour and forbabies born at home with problems might wellfind this statistical observation frustrating. Onthe other hand, emergency measures willalways be needed anyway to deal with the usu-ally more acute problems which can arise whenlabour or birth occurs outside hospital unin-tentionally. Previous surveys have found thatabout a third of births occurring at home wereprecipitate births to women who had booked todeliver in hospital, or were to women who hadmade no arrangements at all."3This has impli-cations for the training ofhome birth practitio-ners and of ambulance staff, particularly para-medics.The authors found that just over 5% of the

babies born to women in their low risk groupwere resuscitated, but that only five out of 65were intubated. This suggested that most couldbe cared for by appropriately trained midwives.They did comment, however, that the propor-tion resuscitated was higher than that observedin a Swedish study4 cited in the report of theBPA Working Party on Neonatal Resuscita-tion.5 It is difficult to interpret this difference,given that the comparison is based on retro-spective data from two separate sources. A col-laborative prospective study, using commondefinitions, would be needed to investigatewhether the difference is a real one or an arte-fact of differences in practice or methods ofdata collection.When it comes to specificity, the authors'

selection procedure leaves a lot to be desired asthey acknowledge themselves. They use crite-ria which are far more stringent than areusually applied in practice, so much so thatonly 4% of deliveries satisfied them. They didnot estimate the proportion ofwomen who didnot satisfy their criteria but went on to have anuncomplicated delivery. It would not besurprising if this was quite high. They point outthat the risk approach, although an imperfectindicator, is used in many booking clinics andmay place "low risk" women into a "high risk"category.The authors use two types of exclusion crite-

ria. The first type is based on adverse eventsand other factors in the individual woman'sclinical background and her current and previ-ous pregnancies. This is therefore specific tothe women concerned. More importantly,some of the factors which may affect decisionsabout place of delivery do not arise until afterinitial booking, so it may be unduly restrictiveto rule out home delivery categorically at thatstage.The second type of criterion is based on

probabilities of adverse events among womenin particular age, parity, height and socialgroupings. Thus primiparous women areexcluded and the age and height criteria arevery restrictive. Unsupported mothers' areexcluded, but not defined. These criteria werefirst put forward in the 1950s and 1960s to

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