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.
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.
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).
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.
Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre