New Dutch study raises troubling questions about the safety of homebirth

A new Dutch study of homebirth appears in the forthcoming issue of the journal Obstetrics and Gynecology. Planned Home Compared With Planned Hospital Births in The Netherlands by van der Kooy et al. is large, comprehensive and raises troubling questions about the safety of homebirth.

The large amount of data is analyzed in a bewildering number of ways, but the bottom line is that homebirth is safe when nothing goes wrong; in the presence of life threatening problems, homebirth increases the risk of death. Moreover, while homebirth with a Dutch midwife in the absence of complications is nearly as safe as hospital birth with a Dutch midwife, the perinatal mortality rate in both groups is 33% higher than comparable risk women delivered in hospitals by obstetricians just across the border in Flanders.

This study is one of many undertaken in the Netherlands to investigate the high perinatal mortality rate.

The debate on the safety of home births continues in the literature ... In The Netherlands, approximately 50% of women give birth under the supervision of a community midwife. The community midwives are independent health care professionals in The Netherlands operating either solely or in group practices.

The proportion of home birth deliveries in The Netherlands has steadily decreased over the last decade but is currently stable at 25% of all births. Several Anglo-Saxon countries are considering the reintroduction of home births based on recent claims of sufficient safety. The reverse trend is observed in The Netherlands, where the debate has intensified since the national perinatal mortality rate showed it to be one of the highest in Europe.

The authors started with a very large and comprehensive database, and analyzed it in a variety of ways. They started with 679,952 births: all the low risk births attended by midwives from 2000-2007. They looked at the difference in perinatal death rates (defined restrictively as intrapartum deaths and neonatal deaths up to 7 days of age) between home and hospital birth, first by analyzing what actually happened, then by constructing hypothetical groups of patients, all of whom were ideal candidates for homebirth.

As primary analysis, we present the results of the natural prospective approach resembling an intention- to-treat analysis. For comparison, we added a perfect guideline approach resembling a per-protocol analysis. The natural prospective approach establishes, within observational constraints, the intrapartum and early neonatal death of planned home compared with planned hospital births.

They further analyzed the data by removing deaths due to the "Big 4": congenital anomalies, premature births, intrauterine growth retardation and low Apgar scores. The decision to analyze the data with these deaths removed is baffling. It's baffling because it removes patients who received potentially substandard midwifery care during pregnancy (failure to diagnose anomalies and intrauterine growth retardation as well as failure to appropriately refer patients delivering before term) and it is baffling because it removes babies in need of expert resuscitation. This group is of prime concern when investigating the safety of homebirth because it is this group that faces the greatest risk when born outside the hospital.

Of note, both groups (real-world and hypothetically perfect) differed substantially by maternal characteristics.

Compared with women who planned birth in the hospital or with an unknown location, the women with a planned home birth were more likely to be multiparous, 25 years of age or older, of Dutch origin, and to live in a privileged neighborhood (all of which are favorable conditions). In home birth women, neonatal case mix compared also favorably. Premature delivery was less common as was the prevalence of a Big 4 condition (natural prospective approach home birth 8.7% compared with hospital 10.8% compared with unknown 10.5%; perfect guideline approach home birth 6.5% compared with hospital 8.2% compared with unknown 7.5%, P <001 in both cases).

In other words, the homebirth group was much lower risk than the hospital birth group.

What did the investigators find?

In the natural prospective approach population, crude mortality risk was significantly lower for women who planned to give birth at home (relative risk 0.80, 95% confidence interval [CI] 0.71– 0.91) ... compared with those who intended to give birth in hospital (P <.05). All maternal and neonatal risk factors, except living in a deprived neighborhood, showed significant effect sizes in agreement with the expected direction. Mortality was significantly increased in neonates with a Big 4 outcome, especially in those with multiple Big 4 conditions (relative risk 276.6, 95% CI 240.3–318.3).

When looking at what actually happened, the death rate at home was lower than in the hospital, but that reflects both the difference in risk factors between the two groups and the difference in "Big 4" bad outcomes between the two groups. After adjusting for these risk factors and differences in Big 4 outcomes, home and hospital had similar perinatal mortality rates:

The nested multivariable logistic regression analysis showed that in the presence of adjusting maternal factors only (model 2), the intended place of birth had no significant effect on outcome. The maternal factors showed risks similar to the univariable (crude) analysis. The addition of Big 4 case mix adjustment (model
3) showed the intended place of birth to be a significant covariable, yet the contrast of planned home birth (odds ratio 1.05, 95% CI 0.91–1.21) compared with a hospital birth (reference <1) turned out to be nonsignificant. The effect of maternal risk factors was affected to a limited degree by the introduction of the Big 4 case mix.

The perfect guideline approach yielded similar results.

What does this mean? It means that when nothing goes wrong at homebirth, it is just as safe as midwife attended hospital birth. Since complications are uncommon, the overall rates of homebirth and hospital birth perinatal mortality are very similar. However, in the event of an unanticipated bad outcome, homebirth has a much higher perinatal mortality rate than midwife attended hospital birth.

In a nod to the BMJ study published by their colleagues last year, which showed that low risk birth with a Dutch midwife (home or hospital) has a higher mortality rate than high risk hospital birth with a Dutch obstetrician, the authors acknowledge that the mortality rate for midwife attended births, both home and hospital, are higher than expected:

... The data from an otherwise very similar country such as Flanders suggest that more favorable results may be expected in low-risk women in general from a hospital-based system. In Flanders, perinatal mortality is approximately 33% less than in The Netherlands, whereas the cesarean delivery rates show little difference.

The authors compare their results with other homebirth studies, noting that home and hospital populations differ markedly in risk profile and that any study of homebirth outcomes must correct for these differences.

Our conclusions apparently contradict those of De Jonge et al who concluded equal intrapartum and early neonatal outcome of planned home birth compared with hospital birth in apparently the same population... Our principal approach (natural prospective approach) compares neonatal mortality in the actual populations delivering at home compared with the hospital, whereas the approach of De Jonge et al compares neonatal mortality in a hypothetical group resembling our perfect guideline approach population.

What's the bottom line?

Homebirth is as safe as hospital birth when nothing goes wrong. But when complications occur unexpectedly at birth, hospital is much safer than home.


This piece first appeared on The Skeptical OB in October 2011.

A stunning indictment of midwives in The Netherlands

Homebirth and midwifery advocates point with pride to a recent study that showed that homebirth with a midwife in the Netherlands is as safe as hospital birth with a midwife (Perinatal mortality and morbidity in a nationwide cohort of 529 688 low-risk planned home and hospital births). They tout this study as evidence that homebirth is as safe as hospital. A new study suggests an entirely different explanation: Dutch midwives have unacceptably high rates of perinatal mortality both at home and in the hospital. Indeed, the perinatal mortality rate for LOW risk women cared for by Dutch midwives is HIGHER than the perinatal mortality rate for HIGH risk women cared for by Dutch obstetricians!

The new study, Perinatal mortality and severe morbidity in low and high risk term pregnancies in the Netherlands: prospective cohort study, appears in this week's issue of the British Medical Journal. The authors explain that the study was undertaken to investigate why the Netherlands has highest perinatal mortality rate in Europe.

Several factors are mentioned as possible explanations for this high mortality, such as differences in registration and maternal characteristics of the Dutch childbearing population, restricted management of premature babies, and the absence of standard screening for congenital anomalies. The numbers of older mothers, multiple pregnancies, and mothers belonging to an ethnic minority are relatively high in the Netherlands. However, this can only partly explain the high perinatal mortality. Whether the Dutch obstetric care system contributes to this relatively high mortality remains unclear.

This is an important question because the Dutch system of maternity care relies primarily on midwives and those midwives perform a relatively high number of homebirths. This study, a cohort study of severe morbidity and mortality of term fetuses or neonates, called ATNICID (Admission of Term Neonates to Intensive Care or Intrauterine Death), was begun in 2007 with the express intent of examining the relationship between the organization of the Dutch maternity care system and the high rate of perinatal mortality.

The study ultimately enrolled 37,735 term infants without congenital anomalies:

16,672 (44.2%) infants of nulliparous women (including 143 (0.9%) twin pregnancies) and 21,063 (55.8%) infants of multiparous women (including 226 (1.1%) twin pregnancies). Data on 91 (0.2%) infants were missing; we excluded these from further analysis... 18,686 (49.5%) infants were born to women who started labour in primary care as low risk, of whom 5492 (29.4%) were referred to secondary care during labour; 13,194 (35.0%) infants were born under the supervision of a midwife in primary care, and 24,450 (64.8%) infants were born under the supervision of a gynaecologist.

The results were astounding:

Of the 60 antepartum stillbirths, 37 occurred in primary care and 23 in secondary care...

Twenty-two intrapartum stillbirths and 14 delivery related neonatal deaths occurred. Infants of pregnant women at low risk had a significantly higher risk of delivery related perinatal death (relative risk 2.33, 1.12 to 4.83), compared with infants of women at high risk whose labour started in secondary care under the supervision of an obstetrician. Infants of women who were referred to secondary care during labour had a 3.66 times higher risk of delivery related perinatal death than did infants of women who started labour in secondary care (relative risk 3.66, 1.58 to 8.46)...

A total of 210 infants were admitted to the NICU:

... resulting in an overall incidence of admission to NICU of 5.58 (4.83 to 6.33) per 1000 live births.... Half of the women (51%, n=107) started labour in primary care. Of these, 70% (n=75) were referred to secondary care during labour... The incidence of admissions to the NICU was 2.43 per 1000 term births in primary care, 13.7 per 1000 term births if referral to secondary care during labour occurred, and 5.45 per 1000 term births managed exclusively in secondary care.

Nearly half the NICU admissions were the result of one cause: asphyxia. Among the 17 infant deaths:

71% (n=12) [were] because of asphyxia and 29% (n=5) because of an infection. Fourteen cases were classified as directly related to circumstances during labour.

Of the 26 deaths related to labor presided over by midwives, 65% were attempted homebirths.

These results are deeply shocking.

We found that delivery related perinatal death was significantly higher among low risk pregnancies in midwife supervised primary care than among high risk pregnancies in obstetrician supervised secondary care. This difference was even greater among the cases that were referred from primary to secondary care during labour. Unfortunately, we were unable to adjust for confounding variables because we used aggregated data from a large birth registry database. However, the results are unlikely to have been overestimated, because risk factors such as low socioeconomic status, higher age, or non-Western ethnicity were more prevalent among the women at high risk. (my emphasis)

The authors express their concern:

In summary, the Dutch obstetric care system is based on the assumptions that pregnant women and women in labour can be divided into a low risk group and a high risk group, that the first group of women can be supervised by a midwife (primary care) and the second group by an obstetrician (secondary care), and that women in the primary care group can deliver at home or in hospital with their own midwife. When complications occur or risk factors arise antenatally, during labour, or in the puerperium in primary care, the women is referred to secondary care. We found that the perinatal death rate of normal term infants was higher in the low risk group than in the high risk group, so the Dutch system of risk selection in relation to perinatal death at term is not as effective as was once thought. This also implies that the high perinatal death rate in the Netherlands compared with other European countries may be caused by the obstetric care system itself, among other factors. A critical evaluation of the obstetric care system in the Netherlands is thus urgently needed.

In contrast to the claims of homebirth and midwifery advocates, the Netherlands is far from being the ideal model of obstetric care. The Netherlands has the highest perinatal mortality in Europe, and midwifery care may very well be the cause of this calamity.


This piece first appeared on The Skeptical OB in November 2010.

The high perinatal mortality rate in The Netherlands.

Homebirth and natural childbirth advocates often approvingly cite the maternity care in the Netherlands. Homebirth rates are the highest in the world (30%, but down considerably and falling every year) and midwives are the mainstay of the system, caring for any woman who does not require the care of a doctor.

What homebirth and natural childbirth advocates fail to realize is that The Netherlands has one the highest perinatal death rate in Europe and a high and rising rate of maternal mortality. Indeed, the Dutch have become so alarmed at the perinatal and neonatal death rates that the government has convened a variety of investigations to determine the cause.

The paper Higher perinatal mortality in The Netherlands than in other European countries: the Peristat-II study, published in a Dutch journal, brought the issue of perinatal mortality into focus:

... In Peristat-II from 22 weeks gestation, after France, The Netherlands had the highest fetal mortality rate (7.0 per 1,000 total number of births). Of all western European countries, The Netherlands had the highest early neonatal mortality rate (3.0 per 1,000 live births). Over the past 5 years the perinatal mortality rate in The Netherlands has dropped from 10.9 to 10.0 per 1,000 total births but this drop has been faster in other countries. CONCLUSION: The Netherlands has a relatively high number of older mothers and multiple pregnancies, but this only partly explains the high Dutch perinatal mortality rate which still ranks unfavourably in the European tables. More research is necessary to gain insight into the prevalence of risk factors for perinatal mortality compared with other European countries. In addition, perinatal health and the quality ofperinatal healthcare deserve a more prominent position in Dutch research programmes.

The government has commissioned researchers at the Erasmus Medical Centre in Rotterdam to oversee the investigation. From the Erasmus MC website:

The Netherlands has a relatively poor position in Europe when it comes to health at the time of birth, in other words, perinatal health. Approximately 10 out of every 1000 children die around the time of birth. In similar other countries this mortality rate can be as much as 30% lower. Of the perinatal deaths in the Netherlands, 70% are stillbirths when counted from the 22nd week of pregnancy. Thirty percent of the perinatal deaths take place in the first week after birth. In Flanders, that is socio-democratically and economically comparable to the Netherlands, the perinatal death rate has been two-thirds of that in the Netherlands for at least 10 years. This means that instead of 1700 cases of perinatal death that occur per year among the 175,000 newborns in the Netherlands, only 1150 cases should occur; an unprecedented large difference. Moreover, within the Netherlands, and particularly in the larger cities such as Rotterdam and The Hague, there are distinct differences between groups of pregnant women.

The ZonMw has commissioned Erasmus MC to carry out the Descriptive study Pregnancy and Childbirth. The aim of the study is to determine knowledge questions and research opportunities to improve the perinatal care in the Netherlands. Aspects studied include patient-related risk factors such as diseases already present, lifestyle and social factors on the one hand and the role of the midwife practices including use of care, risk selection, and quality of care in the Netherlands on the other. The preliminary conclusion is that the unfavorable European position is probably mainly caused by factors in the care system while the differences within the Netherlands and the larger cities are linked to large risk differences between groups on the basis of ethnicity, social deprivation and the neighborhood in which people live. A research agenda has been formulated based on this.

In other words, the government investigation found that one of the main reasons for the high perinatal death rate is the midwife care system including use of care, risk selection, and quality of care.

Not only is perinatal mortality unacceptably high, maternal mortality is high and rising. According to the paper Rise in maternal mortality in the Netherlands, published in the British Journal of Obstetrics and Gynaecology earlier this year:

The overall maternal mortality ratio was 12.1 per 100 000 live births, which was a statistically significant rise compared with the maternal mortality ratio of 9.7 in the period 1983–1992 (OR 1.2, 95% CI 1.0–1.5). The most frequent direct causes were (pre-)eclampsia, thromboembolism, sudden death in pregnancy, sepsis, obstetric haemorrhage and amniotic fluid embolism. The number of indirect deaths also increased, mainly caused by an increase in cardiovascular disorders (OR 2.5, 95% CI 1.4–4.6). Women younger than 20 years and older than 45 years, those with high parity or from nonwestern immigrant populations were at higher risk. Most substandard care was found in women with pre-eclampsia (91%) and in immigrant populations (62%).

Conclusions
Maternal mortality in the Netherlands has increased since 1983–1992. Pre-eclampsia remains the number one cause. Groups at higher risk for complications during pregnancy should be better identified early in pregnancy or before conception, in order to receive preconception advice and more frequent antenatal visits. There is an urgent need for the better education of women and professionals concerning the danger signs, and for the training of professionals in order to improve maternal health care.

In an accompanying commentary, British obstetrician JJ Walker notes that there has been pressure in the UK to adopt the Dutch system of maternity care:

... The fact that there are areas of concern in the Netherlands over rising maternal death ratios, despite their generally high socio-economic profile, as well as the previously documented high level of perinatal mortality, suggests that we should be cautious about moving our pattern of care towards theirs without careful consideration of a potentially adverse effect on maternal and perinatal mortality and morbidity. The UK has improved its safety for both mothers and babies by careful audit and guideline development. Care should be taken not to undo these changes by striving for political correctness.

American homebirth advocates and natural childbirth advocates who point to the Dutch system as a model would do well to heed Dr. Walker's advice.


This piece first appeared on The Skeptical OB in July 2010.