BJOG: Safety of Home Births
Released on 02/04/2008
Author Press Office
NCT Statement on BJOG study – Home births
A new study published in BJOG: An International Journal of Obstetrics and Gynaecology examines the safety of homebirths.
Mary Newburn, Head of Policy Research at NCT (National Childbirth Trust) said;
“In our opinion, the findings in this study are unreliable and may be seriously misleading”.
“We believe there are fundamental weaknesses in its design and also some errors and inconsistencies in the methodology.”
The design of the study is weak in a number of ways.
The study is retrospective and uses data from several different studies and databases compiled for other purposes. This may present problems of missing data, mis-coded cases and recall bias.
To assess the safety of home birth accurately, prospective data is required that is collected for the purpose of the study and follows women through their care and records outcomes for them and their baby.
Further, when comparing the safety of planned home births with planned hospital births, it is vital to have similar samples of women, and to exclude unplanned home births.Methodology
In this study, Mori et al make a series of estimates about unplanned home births and intra-partum related perinatal mortality (IPPM) rates, applying estimates from previous studies to two unrelated datasets.
In particular, their estimates of unplanned home births are unreliable. Two different methods have been used to calculate unplanned home births.² This leads to inaccurate estimates of perinatal mortality rates for planned home births. ENDS
Reference: Mori R, Dougherty M, Whittle M. An estimation of intrapartum-related perinatal mortality rates for booked home births in England and Wales between 1994 and 2003. BJOG 2008; 115:554–559.
For more press information please contact Press Office, National Childbirth Trust, 0208 752 2404 or email firstname.lastname@example.orgReferences:-
1. Unplanned homebirths have poorer outcomes than planned home births as women who conceal their pregnancies are often unattended in labour and have had no antenatal care.
2. One of the estimates of around 66,000 (calculation A) is three times higher than another estimate of 20,000 (category B).
A paper published in the BMJ by Murphy et al, over 20 years ago showed calculation B to be more reliable, yet Mori et al base their conclusions on calculation A. If estimates of IPPM are based on calculation B then IPPM associated with home birth is not different from rates for all births (home birth 0.74; all births 0.79).
Women who transfer to hospital
The Mori et al paper quotes an increased estimated IPPM rate for women who plan a home birth but transfer to hospital. There are three key problems with this:
These are very rough and inaccurate estimates. The paper does not make it clear that the calculation of 6 baby deaths per 1000 women transferred is a rough estimate, not a precise number. The range using two different calculations was anything from 0.78 to 8.37 deaths per 1000 births. To put this in context, the rate for all births was 0.79 per 1000 births.
Over half of the women from the three research studies used by Mori et al to calculate the estimate rate of baby deaths transferred before the start of labour, so they had all their labour care in hospital.
A higher complication rate would be expected for women whose pregnancy is not straightforward, but there is no means of comparing the women planning a home birth (who, for example, might develop pre-eclampsia, or have twins, or have a breech baby) with similar women planning a hospital birth. Women booked for hospital care with these kinds of risk factors will also have a higher complication rate than other women (though no data is provided by Mori et al to allow comparison).
The Birthplace study is underway to address these issues (www.npeu.ox.ac.uk/birthplace)
A typical headline to report this study: "Home-Birth babies at greater risk of dying" - Daily Telegraph.
Home birth to ward increases risk
There may be serious risks for the baby when mothers who chose a home birth are transferred to hospital, a study says.
Researchers writing in the journal BJOG examined all home births over a decade.
While the death rate for births at home was low, if the mother transferred to hospital the risk of losing the baby soared to eight times above average.
Home birth advocates say the study does not consider women who develop problems in hospital. And the deaths of babies numbered just 65, from 10,752 cases.
Less than 2% of women currently opt for a home birth, but the government has promised all prospective mothers the choice by 2009.
A team at the National Collaborating Centre for Women's and Children's Health looked at data on all home births in England and Wales between 1994 and 2003.
Essentially women who opt for a home birth face either a very successful, satisfying outcome, or a potentially disastrous one - there isn't the greyer area that you see with hospital births Professor Philip Steer Editor, BJOG
There were broken down into three sub-sections: planned home births, unplanned home births - when a mother intended to go to hospital but was caught unawares, and a "transferred group" - when women who had planned a homebirth ended up giving birth in hospital.
The death rate among babies whose mothers planned - and did - give birth at home was lower than the average for all births taken together - including those in a hospital, midwife-led unit, as well as at home.
This, the study's authors suggest, was not surprising, given that on the whole only women with few risk factors are likely to be able to book a homebirth and they were thus a self-selecting group.
But when complications did arise for women in this group and she needed to be transferred to hospital, her risk of losing her baby was nearly eight times higher than the national average - and 12 times higher than had she given birth at home.
On average, around 15% of women who have chosen a home birth will be transferred - although the figure is significantly higher for first-time mothers and significantly lower for those who have already had children.
"Essentially women who opt for a home birth face either a very successful, satisfying outcome, or a potentially disastrous one - there isn't the greyer area that you see with hospital births," says Professor Philip Steer, the editor of the BJOG.
"Women's decisions about where and how they give birth must be respected, but it is very important that they are not misled about the risks and are in a position to make an informed choice."
However, the authors conceded that the actual data about transfers was taken from a multitude of studies and was inevitably inconsistent.
"Transfers" did not refer exclusively to women who were rushed to hospital in labour, but included any woman who, having initially chosen a home birth at 12 weeks, ended up giving birth in hospital.
You're not comparing like with like - the study is seriously flawed Mary Newburn NCT
The reasons were also unknown, potentially varying from a change of heart or the desire for more effective pain relief to a major complication.
And the actual numbers are small. In the 11-year period studied, sixty-five babies died after their mothers were transferred to hospital out of a total of 10,752. Childbirth in the UK, experts stress, remains very safe.
The National Childbirth Trust, which wants all women to have the choice of a home birth, says the study should have looked at the number of babies who died in hospital after their mothers developed complications.
"You're not comparing like with like," says Mary Newburn, head of policy at the charity. "The study is seriously flawed."
The Royal College of Midwives said such the research was "welcome but inconclusive".
"The nature of transfer means that complications are anticipated or evident. This principle applies irrespective of place of birth, whether this is at home, in a birth centre or in hospital," said Dame Karlene Davis.
A spokesperson for the Department of Health said: "The department welcomes this article, whose findings will add to the much larger and more detailed study we have already commissioned on safety of place of birth."