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NIHR Signal Birthplace in England follow-up analysis reveals some variation between units delivering maternity care

Published on 19 November 2015

doi: 10.3310/signal-000149

This study is a follow-on analysis of data from the Birthplace in England study. It consists of five sub-studies that further analyse the original Birthplace in England study data. The NIHR funded this study to provide evidence to inform the development of maternity services.

It found that, irrespective of the woman’s ethnic background, age or socioeconomic status, midwife led units for “low risk” women led to fewer interventions with no difference in outcomes compared to obstetric units. However, women having their first birth at home or in a midwife led unit had a high chance (35-45%) of transfer to an obstetric unit. Transfers took on average about 50 to 60 minutes.

Intervention and transfer rates varied between units. This variation was greater than expected by chance, and could not be explained by the characteristics of the women planning birth in the unit. For example, epidurals and other interventions were more common in births which occurred during weekday “office hours” than outside of them. Obstetric units may therefore need to examine why excessive interventions are occurring, and put into place strategies to promote normal births.

The results from this study, combined with the original results of the Birthplace in England study, suggests that freestanding midwife-led units situated not too far from consultant-led obstetric units may achieve the lowest transfer and intervention rates, and increase in the number of “normal” births if they are primarily used by “low risk” women.  However, any changes in the configuration of maternity services should be monitored and evaluated.

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Why was this study needed?

Women can choose to give birth at home, a consultant-led obstetric unit or a midwife-led unit either “alongside” the obstetric unit or “freestanding”, further away from it. Most women in England choose an obstetric unit in a hospital.

The original Birthplace in England study recorded outcomes for women and their babies enrolled from April 2008 to April 2010. It found that women who plan to give birth in a midwife-led unit have fewer interventions, such as an emergency caesarean or birth assisted by forceps, than in an obstetric unit, with no difference in outcome. However over a third of women having their first birth required transfer to an obstetric unit. “Low risk” women who planned home births were also less likely to have an intervention but again, nearly half of women having their first birth were transferred to an obstetric unit and there was a greater risk of harm to the baby.

This additional study used data from the cohort to explore factors influencing interventions, transfers and outcomes in different birth settings in order to support the development and configuration of maternity services.

What did this study do?

The Birthplace in England cohort study comprised 79,774 women. Data were collected from the majority of NHS trusts in England that support home births or have midwife-led units, plus a sample of trusts with obstetric units. Midwives attending the births collected data including maternal characteristics, risk factors known prior to the onset of labour, labour care received, details of transfers, and mother and child outcomes. The study ran from April 2008 to April 2010.

This follow-on project was conducted as a series of five complementary sub-studies, each using collected data from the cohort and addressing a set of research questions related to a specific topic. A range of statistical analyses were used to study associations.

What did it find?

  • Low-risk women, i.e. women without risk factors such as having diabetes, preeclampsia or multiple pregnancies, who plan birth at home or in a midwife-led unit had a lower risk of intervention than low-risk women who plan birth in an obstetric-led unit. This was irrespective of ethnic background, age or socioeconomic status.
  • Low-risk women having their first birth at home or in a midwife led unit had a 35 to 45% chance of transfer to an obstetric unit, compared to a 9 to 13% chance of transfer for low-risk women who had already had a previous baby/birth.
  • In planned births in obstetric units, interventions were more likely to occur during weekday “office hours” (9am to 5pm) than in births outside these hours.
  • Intervention and transfer rates varied between units more so than expected by chance. The variation was not explained by the characteristics of the women planning birth in them.
  • Transfer from a freestanding unit or home took an average of about 50 to 60 minutes from the decision to transfer to first assessment in an obstetric unit, though this was faster for emergencies.
  • Smaller freestanding maternity-led units tended to have higher transfer rates than larger units, as did maternity-led units situated a long distance from the nearest obstetric unit. However, more distant freestanding units tended to be smaller, and it was not possible to determine which was driving the association.

What does current guidance say on this issue?

NICE guidance published in 2014 recommends that all four birth settings are available to all women and that they are given information and advice so they can make an informed decision. Low risk women having their second or subsequent child should be advised that planning to give birth at home or in a midwife‑led unit is suitable for them because the rate of interventions is lower and the outcome for the baby is no different compared with an obstetric unit. Low‑risk women having their first child should be advised that if they plan to have a home birth there is a small increase in the risk of an adverse outcome for the baby. Instead, planning to give birth in a midwifery‑led unit may be suitable for them because the rate of interventions is lower and the outcome for the baby is no different compared with an obstetric unit though there is still a 35 to 40% chance of requiring transfer to hospital.

What are the implications?

Increasing the number of births at home or in midwife-led units is likely to reduce intervention rates in low-risk women, and lead to a greater number of normal births, free of any interventions, such as emergency caesarean section.

Obstetric units may need to examine why excessive interventions are occurring, particularly during office hours, and put into place strategies to promote normal births.

Monitoring and evaluation of any changes in the configuration of maternity care are important.

Including the information about chances of transfer or emergency caesarean section will be useful for women deciding where they plan to give birth. Women at “higher risk” such as women giving birth for the first time, those with a prolonged pregnancy or other conditions should be informed that they are more likely to need transfer to an obstetric unit, if they aim to have their baby outside one.

Citation

Hollowell J, Rowe R, Townend J, et al. The Birthplace in England national prospective cohort study: further analyses to enhance policy and service delivery decision-making for planned place of birth. Health Serv Deliv Res. 2015;3(36).

This project was funded by the National Institute for Health Research HS&DR programme (project number 10/1008/43).

Bibliography

Birthplace in England Collaborative Group, Brocklehurst P, Hardy P, et al. Perinatal and maternal outcomes by planned place of birth for healthy women with low risk pregnancies: the Birthplace in England national prospective cohort study. BMJ. 2011;343:d7400.

NICE. Intrapartum care: care of healthy women and their babies during childbirth. CG190. London: National Institute for Health and Care Excellence; 2014.

NHS Choices. Where to give birth: the options. London: NHS Choices; 2015.

Sandall J. Birthplace in England research-implications of new evidence. J Perinat Educ. 2013 Spring;22(2):77-82.

Why was this study needed?

Women can choose to give birth at home, a consultant-led obstetric unit or a midwife-led unit either “alongside” the obstetric unit or “freestanding”, further away from it. Most women in England choose an obstetric unit in a hospital.

The original Birthplace in England study recorded outcomes for women and their babies enrolled from April 2008 to April 2010. It found that women who plan to give birth in a midwife-led unit have fewer interventions, such as an emergency caesarean or birth assisted by forceps, than in an obstetric unit, with no difference in outcome. However over a third of women having their first birth required transfer to an obstetric unit. “Low risk” women who planned home births were also less likely to have an intervention but again, nearly half of women having their first birth were transferred to an obstetric unit and there was a greater risk of harm to the baby.

This additional study used data from the cohort to explore factors influencing interventions, transfers and outcomes in different birth settings in order to support the development and configuration of maternity services.

What did this study do?

The Birthplace in England cohort study comprised 79,774 women. Data were collected from the majority of NHS trusts in England that support home births or have midwife-led units, plus a sample of trusts with obstetric units. Midwives attending the births collected data including maternal characteristics, risk factors known prior to the onset of labour, labour care received, details of transfers, and mother and child outcomes. The study ran from April 2008 to April 2010.

This follow-on project was conducted as a series of five complementary sub-studies, each using collected data from the cohort and addressing a set of research questions related to a specific topic. A range of statistical analyses were used to study associations.

What did it find?

  • Low-risk women, i.e. women without risk factors such as having diabetes, preeclampsia or multiple pregnancies, who plan birth at home or in a midwife-led unit had a lower risk of intervention than low-risk women who plan birth in an obstetric-led unit. This was irrespective of ethnic background, age or socioeconomic status.
  • Low-risk women having their first birth at home or in a midwife led unit had a 35 to 45% chance of transfer to an obstetric unit, compared to a 9 to 13% chance of transfer for low-risk women who had already had a previous baby/birth.
  • In planned births in obstetric units, interventions were more likely to occur during weekday “office hours” (9am to 5pm) than in births outside these hours.
  • Intervention and transfer rates varied between units more so than expected by chance. The variation was not explained by the characteristics of the women planning birth in them.
  • Transfer from a freestanding unit or home took an average of about 50 to 60 minutes from the decision to transfer to first assessment in an obstetric unit, though this was faster for emergencies.
  • Smaller freestanding maternity-led units tended to have higher transfer rates than larger units, as did maternity-led units situated a long distance from the nearest obstetric unit. However, more distant freestanding units tended to be smaller, and it was not possible to determine which was driving the association.

What does current guidance say on this issue?

NICE guidance published in 2014 recommends that all four birth settings are available to all women and that they are given information and advice so they can make an informed decision. Low risk women having their second or subsequent child should be advised that planning to give birth at home or in a midwife‑led unit is suitable for them because the rate of interventions is lower and the outcome for the baby is no different compared with an obstetric unit. Low‑risk women having their first child should be advised that if they plan to have a home birth there is a small increase in the risk of an adverse outcome for the baby. Instead, planning to give birth in a midwifery‑led unit may be suitable for them because the rate of interventions is lower and the outcome for the baby is no different compared with an obstetric unit though there is still a 35 to 40% chance of requiring transfer to hospital.

What are the implications?

Increasing the number of births at home or in midwife-led units is likely to reduce intervention rates in low-risk women, and lead to a greater number of normal births, free of any interventions, such as emergency caesarean section.

Obstetric units may need to examine why excessive interventions are occurring, particularly during office hours, and put into place strategies to promote normal births.

Monitoring and evaluation of any changes in the configuration of maternity care are important.

Including the information about chances of transfer or emergency caesarean section will be useful for women deciding where they plan to give birth. Women at “higher risk” such as women giving birth for the first time, those with a prolonged pregnancy or other conditions should be informed that they are more likely to need transfer to an obstetric unit, if they aim to have their baby outside one.

Citation

Hollowell J, Rowe R, Townend J, et al. The Birthplace in England national prospective cohort study: further analyses to enhance policy and service delivery decision-making for planned place of birth. Health Serv Deliv Res. 2015;3(36).

This project was funded by the National Institute for Health Research HS&DR programme (project number 10/1008/43).

Bibliography

Birthplace in England Collaborative Group, Brocklehurst P, Hardy P, et al. Perinatal and maternal outcomes by planned place of birth for healthy women with low risk pregnancies: the Birthplace in England national prospective cohort study. BMJ. 2011;343:d7400.

NICE. Intrapartum care: care of healthy women and their babies during childbirth. CG190. London: National Institute for Health and Care Excellence; 2014.

NHS Choices. Where to give birth: the options. London: NHS Choices; 2015.

Sandall J. Birthplace in England research-implications of new evidence. J Perinat Educ. 2013 Spring;22(2):77-82.

The Birthplace in England national prospective cohort study: further analyses to enhance policy and service delivery decision-making for planned place of birth

Published on 1 August 2015

Hollowell, Jennifer,Rowe, Rachel,Townend, John,Knight, Marian,Li, Yangmei,Linsell, Louise,Redshaw, Maggie,Brocklehurst, Peter,Macfarlane, Alison,Marlow, Neil,McCourt, Christine,Newburn, Mary,Sandall, Jane,Silverton, Louise

Health Services and Delivery Research Volume 3 , 2015

Background Evidence from the Birthplace in England Research Programme supported a policy of offering low risk women a choice of birth setting, but a number of unanswered questions remained. Aims This project aimed to provide further evidence to support the development and delivery of maternity services and inform women s choice of birth setting: specifically, to explore maternal and organisational factors associated with intervention, transfer and other outcomes in each birth setting in low risk and higher risk women. Design Five component studies using secondary analysis of the Birthplace prospective cohort study (studies 2 5) and ecological analysis of unit/NHS trust-level data (studies 1 and 5). Setting Obstetric units (OUs), alongside midwifery units (AMUs), freestanding midwifery units (FMUs) and planned home births in England. Participants Studies 1 4 focused on low risk women with term pregnancies planning vaginal birth in 43 AMUs (n = 16,573), in 53 FMUs (n = 11,210), at home in 147 NHS trusts (n = 16,632) and in a stratified, random sample of 36 OUs (n = 19,379) in 2008 10. Study 5 focused on women with pre-existing medical and obstetric risk factors ( higher risk women). Main outcome measures Interventions (instrumental delivery, intrapartum caesarean section), a measure of low intervention ( normal birth ), a measure of spontaneous vaginal birth without complications ( straightforward birth ), transfer during labour and a composite measure of adverse perinatal outcome ( intrapartum-related mortality and morbidity or neonatal admission within 48 hours for > 48 hours). In studies 1 and 3, rates of intervention/maternal outcome and transfer were adjusted for maternal characteristics. Analysis We used (a) funnel plots to explore variation in rates of intervention/maternal outcome and transfer between units/trusts, (b) simple, weighted linear regression to evaluate associations between unit/trust characteristics and rates of intervention/maternal outcome and transfer, (c) multivariable Poisson regression to evaluate associations between planned place of birth, maternal characteristics and study outcomes, and (d) logistic regression to investigate associations between time of day/day of the week and study outcomes. Results Study 1 unit-/trust-level variations in rates of interventions, transfer and maternal outcomes were not explained by differences in maternal characteristics. The magnitude of identified associations between unit/trust characteristics and intervention, transfer and outcome rates was generally small, but some aspects of configuration were associated with rates of transfer and intervention. Study 2 low risk women planning non-OU birth had a reduced risk of intervention irrespective of ethnicity or area deprivation score. In nulliparous women planning non-OU birth the risk of intervention increased with increasing age, but women of all ages planning non-OU birth experienced a reduced risk of intervention. Study 3 parity, maternal age, gestational age and complicating conditions identified at the start of care in labour were independently associated with variation in the risk of transfer in low risk women planning non-OU birth. Transfers did not vary by time of day/day of the week in any meaningful way. The duration of transfer from planned FMU and home births was around 50 60 minutes; transfers for potentially urgent reasons were quicker than transfers for non-urgent reasons. Study 4 the occurrence of some interventions varied by time of the day/day of the week in low risk women planning OU birth. Study 5 higher risk women planning birth in a non-OU setting had fewer risk factors than higher risk women planning OU birth and these risk factors were different. Compared with low risk women planning home birth, higher risk women planning home birth had a significantly increased risk of our composite adverse perinatal outcome measure. However, in higher risk women, the risk of this outcome was lower in planned home births than in planned OU births, even after adjustment for clinical risk factors. Conclusions Expansion in the capacity of non-OU intrapartum care could reduce intervention rates in low risk women, and the benefits of midwifery-led intrapartum care apply to all low risk women irrespective of age, ethnicity or area deprivation score. Intervention rates differ considerably between units, however, for reasons that are not understood. The impact of major changes in the configuration of maternity care on outcomes should be monitored and evaluated. The impact of non-clinical factors, including labour ward practices, staffing and skill mix and women s preferences and expectations, on intervention requires further investigation. All women planning non-OU birth should be informed of their chances of transfer and, in particular, older nulliparous women and those more than 1 week past their due date should be advised of their increased chances of transfer. No change in the guidance on planning place of birth for higher risk women is recommended, but research is required to evaluate the safety of planned AMU birth for women with selected relatively common risk factors. Funding The National Institute for Health Research Health Services and Delivery Research programme.

Most women give birth in an NHS hospital maternity unit. However, giving birth in England is generally safe wherever the mother chooses to have her baby. There is a slightly increased risk of a poor outcome for the baby for women having their first birth at home according to the Birthplace in England cohort. This risk increases from about five in 1,000 for a hospital birth to nine in 1,000, almost 1%, for a home birth.

In 2010 there were 53 alongside midwifery units and 59 freestanding midwifery units in operation in England, representing around 39% of all available maternity units. Of the 152 trusts providing maternity care, around half did not offer care in a midwifery unit of any kind. Births planned in midwife units and at home made up fewer than 10% of all births, but there was notable geographical variation in this proportion.

Expert commentary

This research has informed the debate about place of birth across the United Kingdom. It was of sufficient size to provide some information about safety for the new born and demonstrated that new born adverse events are uncommon in all places of birth. It showed that even if there is a difference in adverse outcome the actual difference in the absolute rate of those adverse events must be very small. By demonstrating that the outcomes for women are better in places of birth outside of a traditional Consultant led labour ward it has informed the decision by NICE to advise Commissioners to ensure that women have access to options in terms of place of birth according to their preference. This has led to wider development of midwifery led units and to greater encouragement of home birth. This provides women with greater choice about place of birth. Monitoring any changes in adverse outcomes with the change in policy will be required to validate this research in the future.

Professor Derek Tuffnell, Consultant Obstetrician and Gynaecologist, Bradford Teaching Hospitals NHS Foundation Trust