BMJ No 7068 Volume 313

General Practice Paper Saturday 23 November 1996

Outcome of planned home and planned hospital births in low risk pregnancies: prospective study in midwifery practices in the Netherlands

T A Wiegers, M J N C Keirse, J van der Zee, G A H Berghs Abstract

Objective - To investigate the relation between the intended place of birth (home or hospital) and perinatal outcome in women with low risk pregnancies after controlling for parity and social, medical, and obstetric background.

Design - Analysis of prospective data from midwives and their clients.

Setting - 54 midwifery practices in the province of Gelderland, Netherlands.

Subjects - 97 midwives and 1836 women with low risk pregnancies who had planned to give birth at home or in hospital.

Main outcome measure - Perinatal outcome index based on "maximal result with minimal intervention" and incorporating 22 items on childbirth, 9 on the condition of the newborn, and 5 on the mother after the birth.

Results - There was no relation between the planned place of birth and perinatal outcome in primiparous women when controlling for a favourable or less favourable background. In multiparous women, perinatal outcome was significantly better for planned home births than for planned hospital births, with or without control for background variables.

Conclusions - The outcome of planned home births is at least as good as that of planned hospital births in women at low risk receiving midwifery care in the Netherlands.

Introduction

In the Dutch maternity care system midwives are qualified to provide independent care for women with uncomplicated pregnancies.(1)(2) They also identify and select the women who, because of existing or anticipated problems, require care from an obstetrician.(1)(3) Twenty five years ago, women receiving primary care all gave birth at home, but since the 1970s they have been able to choose between home birth and hospital birth under the care of a midwife or general practitioner. This has led to a substantial reduction in home births (from 69% of all births in 1965 to 31% in 1991)(4) and an increase in the proportion of births attended by midwives (from 35% in 1965 to 46% in 1992). About half of births attended by midwives now occur in hospital, with women and their babies generally being discharged within a few hours after birth.

There is growing concern among primary care givers that these short-stay hospital births (termed "poliklinische bevallingen") enhance the risk of medicalisation and may ultimately eliminate the home birth option. Indeed, referral to an obstetrician occurs more frequently for women with a planned hospital birth than for those choosing home birth.(5) The reasons for this difference are unclear. Self selection may be an important confounder, with the healthiest and most affluent women choosing home birth. Also the choice of home or hospital may influence referral to specialist care, as resources are more likely to be used if they are closer at hand.

We prospectively studied results of planned home births and planned hospital births in women with low risk pregnancies receiving care from midwives. We wished to assess whether the planned place of birth would lead to differences in perinatal outcome after the confounding effects of obstetric, medical, and social background were controlled for.

Patients and methods

Study design

The study was conducted prospectively in two periods between 1990 and 1993 among women with low risk pregnancies receiving midwifery care in the province of Gelderland. A total of 97 midwives in 54 practices enlisted 2301 women, who signed an informed consent form and received a questionnaire about their social background and their preference for birth at home or in hospital. The midwives also received questionnaires about their clients, one to complete before delivery and one afterwards. A copy of the birth notification form (a voluntary registration system used by most midwives and obstetricians) with data on medical and obstetric background, labour, and delivery was added to the completed questionnaires.

For 294 women (13.8%) the birth notifications indicated obstetric referral before the onset of labour, which was an exclusion criterion, and for another 171 (8.0%) information from the midwives could not be checked against birth notifications because they were not available. The study population thus consisted of 1,836 women, 840 primiparae and 996 multiparae, of whom 1,140 had chosen home birth and 696 hospital birth. For 116 (6.3%) women, information was confined to what had been received from their midwife and the birth notification form; these women were excluded only from the subanalyses relating social background to outcome.

Data analysis

Data variables were divided into background and outcome variables according to whether the variable was or could be known before the onset of labour. A value of 1 or 0 was awarded to each, based on the optimality concept originally developed by Prechtl(6) and Touwen et al,(7) in which optimality indicates "the best possible"; it avoids judgments on what is normal or abnormal when defining, for example, "no episiotomy" as optimal. The items were then summed into separate indexes for perinatal background and perinatal outcome,(8) reflecting the number of optimal items in each index.

The perinatal background index,(8) consisting of 31 items, considers as "best possible" the absence of any social, medical, or obstetrical problem before and during pregnancy. Because of its expected skewness in a low risk population and the poor internal consistency expected with many unrelated items (verified by Cronbach's alpha=0.29),(9) the index was used in a simplified, dichotomous manner. Women at or above the median were considered to have a relatively favourable background, the others as having a less favourable background.

The perinatal outcome index consists of 36 items, of which 22 relate to childbirth, nine to the condition of the newborn, and five to the condition of the mother afterwards.(8) Optimal values were based on the principle that a maximally healthy mother and baby with minimal intervention for both of them constitutes the best possible birth.(8)(10) The perinatal outcome index therefore considers not only the result, but also the means by which it is achieved.

Primiparous women and multiparous women were considered separately because of well known differences in outcome. All analyses were based on the planned rather than the actual place of birth because referral to hospital during labour is usually indicative of anticipated or existing problems. Including these women among hospital births would bias the results of planned hospital births negatively and home births positively.

Power analysis, based on detecting a significant difference in the combined frequency of non-optimal factors during and after childbirth, led us to aim for a sample size of 1600 women, with approximately half being multiparous and preferably half choosing hospital birth. Because women in Gelderland more often choose home than hospital birth, only women choosing hospital birth were recruited in the final four months of the study.

Differences in individual background and outcome items were assessed by the chi-2 test and differences in the composite indexes by Student's t test.

Results

Table 1 shows the various perinatal outcomes in relation to the planned place of birth. Interventions - including referral, medication, and episiotomy - were more common in primiparous than parous women, confirming the need to consider these women separately. In primiparous women, the individual outcomes showed few differences between home and hospital. Intervals longer than 12 hours between rupture of membranes and birth, "other problems" (including the need for sedation), and neonatal problems in the first 24 hours (including benign items, such as checkup after instrumental delivery or blood glucose measurement, that cause mothers to worry) occurred more often in planned hospital births than in planned home births (table 1). In multiparous women there were more differences between planned hospital births and planned home births: rates of referral during labour, inadequate progress, perineal laceration, episiotomy, medication in third stage of labour, placental retention, postpartum haemorrhage, and blood transfusion (table 1). Primiparous women (t=1.99, P<0.05) and multiparous women (t=5.56, P<0.001) with a planned home birth scored better on the perinatal outcome index than those with planned hospital birth.

Table 1 - Non-optimal characteristics in perinatal outcome index among planned home and planned hospital births in primiparous and multiparous women
	% (No) of primiparous women (n = 840)		% (No) of multiparous women (n = 996)
Non-optimal outcome	Home births (n = 471)	Hospital births (n = 369)	Home births (n = 669)	Hospital births (n = 327)
Labour and delivery
Medication in first stage labour	21.2 (100)	23.6 (87)	6.1 (41)	8.9 (29)
Ruptured membranes for >12 hours	13.4 (63)	19.0 (70)*	6.4 (43)	7.3 (24)
Amniotic fluid not clear	14.2 (67)	16.5 (61)	12.7 (85)	14.1 (46)
Duration first stage >10 hours	24.6 (116)	22.8 (84)	3.7 (25)	6.4 (21)
Duration second stage >60 minutes	28.9 (136)	28.7 (106)	1.3 (9)	1.8 (6)
Non-cephalic presentation at birth	3.2 (15)	5.1 (19)	1.9 (13)	1.8 (6)
Assisted delivery	29.5 (139)	29.8 (110)	4.3 (29)	6.1 (20)
Perineal laceration	78.3 (369)	74.8 (276)	52.0 (348)	63.0 (206)**
Episiotomy	52.4 (247)	52.8 (195)	15.8 (106)	25.1 (82)***
Referral to specialist care in labour	36.7 (173)	40.7 (150)	8.7 (58)	12.8 (42)***
Insufficient cervical dilatation	8.9 (42)	9.2 (34)	0.9 (6)	2.8 (9)*
Inadequate progress in second stage	12.1 (57)	9.5 (35)	0.4 (3)	1.2 (4)
Fetal distress	4.5 (21)	4.9 (18)	0.6 (4)	0.9 (3)
Induction or augmentation of labour	3.6 (17)	5.1 (19)	1.9 (13)	2.1 (7)
Instrumental vaginal delivery	13.8 (65)	15.7 (58)	1.2 (8)	1.2 (4)
Caesarean section	3.0 (14)	4.1 (15)	0.1 (1)	0.6 (2)
Suturing third degree perineal tear	1.5 (7)	1.4 (5)	0.6 (4)	0.6 (2)
Medication in third stage labour	60.5 (285)	65.9 (243)	37.2 (259)	59.3 (194)***
Placental retention	0.4 (2)	0.8 (3)	0.7 (5)	2.8 (9)*
Blood loss 1000 ml or more	1.9 (9)	4.1 (15)	0.6 (4)	3.7 (12)***
Blood transfusion	0.8 (4)	1.1 (4)	0	1.8 (16)**
Other problems (including need for sedation)	10.4 (49)	19.0 (70)***	5.2 (35)	9.8 (32)*
Neonatal condition
Non-optimal birth weight	17.4 (82)	17.3 (64)	16.6 (111)	19.0 (62)
<10th centile	4.9 (23)	8.9 (33)	6.1 (41)	5.2 (17)
>90th centile	12.5 (59)	8.4 (31)	10.5 (70)	13.8 (45)
Apgar score <9 at 5 minutes	7.0 (33)	9.2 (34)	4.5 (30)	3.7 (12)
Perinatal death	0	0.5 (2)	0.6 (4)	0
Transfer to neonatal ward	11.7 (55)	16.5 (61)	4.5 (30)	7.0 (23)
Congenital anomalies	1.5 (7)	2.4 (9)	1.3 (9)	3.1 (10)
Birth trauma	0.6 (3)	0.5 (2)	0.6 (4)	0.9 (3)
Problems in first 24 hours	16.6 (78)	25.7 (95)**	4.5 (30)	11.0 (36)***
Problems in first week	7.0 (23)	6.8 (25)	2.7 (18)	3.1 (10)
Non-optimal gestational age	4.9 (23)	5.1 (19)	5.0 (33)	2.8 (9)
<37 weeks	2.1 (10)	2.7 (10)	1.1 (7)	1.3 (4)
42 or more weeks	2.8 (13)	2.4 (9)	3.9 (26)	15. (5)
Condition of the mother after birth
Mastitis	0	0	0	0.3 (1)
Endometritis	0	0.5 (2)	0.1 (1)	0
Cystitis	0	0	0.1 (1)	0.3 (1)
Medication in puerperium	0	0	0.3 (2)	0.3 (1)
Other problems	0.4 (2)	0.3 (1)	0	0.6 (2)*
P<0.05; ** P<0.01; *** P<0.001.

Background characteristics differed little between women choosing home or hospital birth (table 2). Primiparous women from ethnic minorities, those with uncertain dates, and those not attending antenatal classes more often chose hospital. Multiparous women were more likely to choose a hospital birth if they belonged to an ethnic minority; had a non-optimal body mass (Quetelet index outside the range 18.8-24.2; P<0.05); had a history of obstetric complications, preterm birth, or instrumental delivery; or had received medication (including vitamins and iron) in pregnancy (table 2).

Table 2 - Percentage non-optimal characteristics in the perinatal background index among planned home and planned hospital births in primiparous and multiparous women
	% (No) of primiparous women (n = 840)		% (No) of multiparous women (n = 996)
Non-optimal background	Home birth (n = 471)	Hospital birth (n = 369)	Home birth (n = 669)	Hospital birth (n = 327)
Social and medical background
Single mother****	2.2 (10)	2.7 (9)	0.8 (5)	2.4 (7)
Ethnic minority****	2.1 (10)	5.2 (19)*	2.2 (15)	5.6 (18)*
No attendance at antenatal classes****	13.7 (61)	20.9 (70)*	41.8 (265)	41.6 (119)
Smoking****	25.4 (113)	29.2 (98)	25.8 (116)	24.9 (72)
Alcohol use >2 glasses a week****	4.3 (19)	3.6 (12)	5.4 (35)	4.5 (13)
Drug intake****	0.2 (1)	0.9 (3)	0.5 (3)	0
Non-optimal Quetelet index*	29.0 (128)	23.5 (77)	27.9 (176)	35.6 (99)*
<18.8	6.2 (27)	5.5 (18)	6.6 (42)	5.4 (15)
>24.2	22.8 (101)	18.0 (59)	21.3 (134)	30.2 (84)
Non-optimal maternal age	18.0 (83)	21.9 (79)	43.8 (288)	45.1 (145)
<20 years	0.6 (2)	1.7 (6)	0	0
>31 years	17.4 (81)	20.2 (73)	43.8 (288)	45.1 (145)
Pre-existent hypertension or diabetes	0.4 (2)	0	0	0
Reproductive history
History of infertility	0.2 (1)	0.8 (3)	0.1 (1)	0.3 (1)
More than one abortion	1.9 (9)	0.8 (3)	4.8 (32)	4.0 (13)
Preterm birth <28 weeks	0	0	0.4 (3)	0.6 (2)
Preterm birth 28-36 weeks	0	0	0.3 (2)	1.8 (6)*
Intrauterine fetal death	0	0	0	0.3 (1)
Instrumental (vaginal) delivery	0	0	1.9 (13)	8.0 (26)***
Caesarean section	0	0	0	0.6 (2)
Infant with low weight for gestation	0	0	0.9 (6)	0
Pregnancy induced hypertension	0	0	0.4 (3)	0.6 (2)
Complications in pregnancy	0	0	0.4 (3)	3.7 (12)***
Present pregnancy
Vaginal bleeding	1.1 (5)	1.9 (7)	1.6 (11)	2.1 (7)
Pre-eclampsia	1.1 (5)	2.2 (8)	0.6 (4)	1.5 (5)
Haemoglobin <6.8 mmol/l	14.2 (69)	18.4 (68)	18.8 (126)	23.9 (78)
Diastolic blood pressure >90 mm Hg	4.9 (23)	5.1 (19)	3.4 (23)	2.8 (9)
Uncertain dates	4.9 (23)	8.7 (32)*	3.9 (26)	5.8 (19)
Rhesus sensitisation	0	0	0.1 (1)	0
Other complications	14.2 (67)	13.6 (50)	10.5 (70)	10.4 (34)
Specialist advice required in pregnancy****	16.5 (76)	18.9 (69)	16.0 (106)	21.0 (68)
Non-optimal No of antenatal visits****	13.5 (62)	14.1 (51)	16.9 (112)	10.5 (34)*
<10	11.3 (52)	11.1 (40)	16.2 (107)	9.9 (32)
>15	2.2 (10)	3.0 (11)	0.7 (5)	0.6 (2)
Amniocentesis	0.2 (1)	0	2.2 (15)	1.8 (6)
Cardiotocography during pregnancy	1.7 (8)	2.7 (10)	1.9 (13)	2.4 (8)
Drugs prescribed or taken in pregnancy****	78.6 (341)	77.8 (242)	83.1 (518)	89.0 (242)*
*P<0.05; **P<0.01; ***P<0.001; **** Some missing data in this category were accounted for in the percentages.

The median value of the perinatal background index (our cutoff between favourable and unfavourable) was 29 points for primiparous women and 28 points for multiparous women. A statistical difference in background between planned home births and planned hospital births was found for primiparous women (chi-2 = 4.21, P = 0.04 compared to chi-2 = 3.60, P = 0.06 in multiparous women).

Table 3 shows the relation between the perinatal outcome index and the planned place of birth, after control for favourable or unfavourable background. After controlling for background, we found no difference in perinatal outcome between planned home birth and planned hospital birth in primiparous women. In multiparous women, the perinatal outcome index controlled for background was significantly better with planned home birth than with planned hospital birth (table 3).

Table 3 - Perinatal outcome index in planned home births and planned hospital births controlled for background variables in low risk pregnancies
Characteristics of women	Mean perinatal outcome index (SD)	Difference (95% confidence interval)
Primiparous women
Background relatively favourable (index 29 or more)
Home birth planned (n = 223)	31.56 (3.17)	0.60 (-0.10 to 1.30)
Hospital birth planned (n = 133)	30.96 (3.50)
Background relatively unfavourable (index <29)
Home birth planned (n = 182)	30.63 (3.57)	0.24 (-0.55 to 1.03)
Hospital birth planned (n = 151)	30.39 (3.75)
Multiparous women
Background relatively favourable (index 28)
Home birth planned (n = 367)	34.17 (1.85)	0.90 (0.52 to 1.28)
Hospital birth planned (n = 140)	33.27 (2.24)
Background relatively unfavourable (index <28)
Home birth planned (n = 215)	33.69 (2.45)	0.73 (0.17 to 1.29)
Hospital birth planned (n = 111)	32.96 (2.38)

Discussion

Measuring perinatal outcome

Measuring the quality of maternity care has never been easy. For many years, perinatal mortality rates were used for this purpose, often with little regard for the value and validity of such data.(11) Now, with rates well below 10 per 1000 births, they have lost virtually all of their utility for measuring quality of care in the Western world. Other measures have yet to find acceptance, but it is unlikely that a single measure will ever be satisfactory for a process that involves mother and baby and for which the end result is not the only outcome that matters. We therefore opted for a differentiated approach that considers both the mother and the baby and that takes both the results and the way in which they are achieved into account. To this end and with a view to obtaining a single measure for maximal outcome with minimal intervention(8)(10) we constructed a composite perinatal outcome index based on an optimality concept developed in the 1970s for identifying a cohort of infants with a flawless start in life.(6)(7)

Outcome in relation to background

Using this tool we compared the outcomes of planned home births with those of planned hospital births for primiparous and multiparous women after controlling for the confounding effects of social, medical, and obstetric background. Without control for this background, the perinatal outcome in primiparous women was significantly better for planned home births than for planned hospital births. This is mainly because nulliparous women with a less favourable background tend to prefer hospital, whereas those with a favourable background tend to choose home birth. This may be different in other countries, but it is not unexpected in the Netherlands, where home birth has been an approved option for a long time.(1)(5) (12) After background variables were controlled for, the perinatal outcome for primiparous women with low risk pregnancies was similar for those who planned home births and those who planned hospital births.

For multiparous women with low risk pregnancies, the perinatal outcome of planned home birth was significantly better than that of planned hospital birth, whether or not background was controlled for. A closer look at the background characteristics shows that multiparous women with a complicated previous pregnancy, including instrumental delivery in our study, were more likely to opt for hospital birth than for home birth. Their history may put them at higher risk of encountering problems again, and this may account for some difference in outcome between home and hospital. However, the multiparous women in our study were at low risk and their history would not have prompted referral to an obstetrician. We also analysed our data after excluding women with a less than optimal obstetric history, and the perinatal outcome index remained better for planned home birth than planned hospital birth (t=4.75, P<0.001). Further research will be necessary to determine how much of the difference in outcome can be attributed to obstetric history and how much to the chosen place of birth. In the meantime and on the basis of our results, the place of birth seems to affect perinatal outcome in women at low risk.

Impact of choice

Ideally - and particularly when offset against virtually 100% hospital births in the rest of Europe - better evidence is needed before generalisations are made on the merits of planned home birth. Such evidence is not easy to gather. It is well known that a variety of psychological factors can influence people's health and interfere with medical treatment. In obstetrics, levels of anxiety have been found to predict obstetric complications.(13) Choice itself (allowing women to choose home or hospital birth) may influence levels of anxiety and apprehension and thereby also the outcome of maternity care. Evidently, the elimination of choice - as would be necessary in a randomised trial - could by itself have a major impact on perinatal outcome by inducing insecurity and anxiety in women assigned to give birth in a manner that they do not prefer. In areas where the patient's choice has a profound effect on outcome, random comparisons eliminating choice will give unreliable estimates of true differences.(14) Therefore, in the Netherlands, where choosing between home or hospital birth is an integral feature of the system, randomised controlled trials between home birth and hospital birth would not produce generalisable results even if it were possible to mount such trials.

Our research has shown that, for women with low risk pregnancies in the Netherlands, choosing to give birth at home is a safe choice with an outcome that is at least as good as that of planned hospital birth. We also found indications that there is some self selection among women who can decide for themselves where to have their baby, and that this preordains outcome, albeit to a limited extent. It is important, therefore, that the home birth option remains available, but especially that women at low risk are really given a free choice.

References

1 Keirse M J N C. Interaction between primary and secondary antenatal care, with particular reference to the Netherlands. In: Enkin M, Chalmers I, eds. Effectiveness and satisfaction in antenatal care. London: Heinemann, 1982:222-33.

2 Van Teijlingen E, McCaffery P. The profession of midwife in the Netherlands. Midwifery 1987;3:178-86.

3 Ziekenfondsraad. Verloskundige indicatielijst 1987: final report of the working party to adjust the Kloostermanlist (WBK). Amstelveen: Ziekenfondsraad, 1987.

4 Central Bureau voor de Statistiek. Births by obstetric assistance and place of delivery, 1991. Maandber Gezondheid (CBS) 1993;12(2):19-31.

5 Damstra-Wijmenga S M I. Home confinement: the positive results in Holland. J R Coll Gen Pract 1984;256:425-30.

6 Prechtl H F R. The optimality concept. Early Hum Dev 1980;4:201-5.

7 Touwen B C L, Huisjes H J, Jurgens-van der Zee A D, Bierman-van Eendenburg M E C, Smrkovsky M, Olinga A A. Obstetrical condition and neonatal neurological morbidity. An analysis with the help of the optimality concept. Early Hum Dev 1980;4:207-28.

8 Wiegers T A, Keirse M J N C, Berghs G A H, van der Zee J. An approach to measuring quality of midwifery care. J Clin Epidemiol 1996;49:319-25.

9 Carmines E G, Zeller R A. Reliability and validity assessment. Beverly Hills and London: Sage, 1979.

10 Enkin M W, Keirse M J N C, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1995: 389.

11 Keirse M J N C. Perinatal mortality rates do not contain what they purport to contain. Lancet 1984;i:1166-9.

12 Treffers P E, Eskes M, Kleiverda G, van Alten D. Home births and minimal medical interventions. JAMA 1990;264:2203-8.

13 Crandon A J. Maternal anxiety and obstetric complications. J Psychosom Res 1979;23:109-11.

14 McPherson K. The best and the enemy of the good: randomised controlled trials, uncertainty, and assessing the role of patient choice in medical decision making. J Epidem Community Health 1994;48:6-15.

NIVEL
(Netherlands Institute of Primary Health Care),
PO Box 1568,
3500 BN Utrecht,
Netherlands

T A Wiegers, research fellow
J van der Zee, director
G A H Berghs, research fellow

Department of Obstetrics and Gynaecology,
Flinders University of South Australia,
Flinders Medical Centre,
GPO Box 2100,
Adelaide,
SA 5001,
Australia

M J N C Keirse, professor

Correspondence to: Mrs Wiegers.

Funding: This study was supported by grant 28-1644 from the Praeventiefonds, The Hague.
Conflict of interest: None.
(Accepted 7 August 1996)