The study published this month in the online journal BMJ Open re-examined the risk to mothers and babies of being cared for by midwives in their first year of practice. It concluded that there was no increased risk of baby death (perinatal mortality) associated with a baby’s mother being cared for by a new graduate midwife compared to a more experienced midwife.
The study did find a higher rate of baby deaths (an extra 1.5 more deaths per 1000 births) for women cared for by new graduate midwives but said once you took into account the higher risk level of the new graduates’ clients – which were more often from higher risk ethnic groups, having their first baby, smokers, overweight and poorer – then there was no statistically significant difference in the safety of care provided by new or experienced midwives.
The New Zealand College of Midwives welcomed the study as confirming care by New Zealand midwifery graduates is ‘excellent’. Alison Eddy, the College’s deputy chief executive said the profession was reassured that the four year midwifery degree and Midwifery First Year of Practice programmes (MFYP) were training and supporting graduate midwives to provide safe, quality care.
Eddy noted that the research found that graduate midwives were more likely to be providing care for women with existing health or social concerns associated with a higher perinatal mortality risk. The research authors say the reason new graduates had a higher proportion of high risk clients might be because women with higher risk factors may not seek out a midwife until later into their pregnancy, when established midwives already have a full caseload.
“There is a need to address this inequity of access to care,” said Eddy. “And to ensure increased support for midwives providing that care.”
The fresh analysis followed midwives being critical of the methodology of a 2015 New Zealand study, led by women’s health researcher Dr Beverley Lawton, that found a 30 per cent higher chance of perinatal mortality (an extra 2 deaths per 1000 births) if a mother was cared for by a midwife in her first year of practice.
The Ministry of Health supported Auckland epidemiologist Dr Lynne Sadler to lead a research team – including obstetrician Michelle Wise, College of Midwives president Deborah Pittam and Midwifery Council chair Dr Judith McAra-Couper – to re-analyse baby birth and data including the different risk level of the mothers being cared for new graduate midwives and their more experienced colleagues.
Nearly 345,000 births analysed
Each year about 60 000 babies are born in New Zealand and 600–700 babies suffer perinatal death which is defined as either a stillbirth (a baby born from 20 completed weeks gestation in utero) or a neonatal death (when a baby dies within first four weeks of life).
The Lawton study had looked at 233,215 births between 2005-2009. The Sadler study initially sought to re-analyse that 2005-2009 birth cohort and compare that with births up to 2014. A lack of data on whether midwifery care was provided for by hospital or community midwives for the 2005-2007 births meant the Sadler study changed its focus to the 344,871 births and 2045 perinatal deaths between 2008-2014 where it was known the mother registered with a community midwife lead maternity carer (LMC).
The Sadler study found that in this time nearly 20,000 babies were born to mothers being cared for my midwives in their first year of practice and of those babies 148 were perinatal deaths – a rate of 7.42 deaths per 1000 births. This compared to nearly 300,000 babies born to midwives known to have a year or more experience who had a perinatal mortality rate of 5.85 deaths per 1000 births.
But the study also gathered data on the risk factors of the midwives’ clients and found that graduate midwives were more likely to be caring for women at higher risk of losing their babies – including teenager mothers, obese women and women living in the poorest communities – than their more experienced colleagues.
“Once mother’s age, number of prior births, ethnicity and socioeconomic deprivation are accounted for, there is no longer an increase in risk of baby death for women cared for by midwives in their first year of practice,” said the authors. “This is an important and reassuring finding.”
Eddy said the College had been a loud critic of the Lawton paper and was pleased its position had been vindicated.
The study authors also noted that the findings suggested an inequity of access for higher-risk, vulnerable women to experienced midwives.
They said more research was needed to understand why more women at higher clinical risk booked with new graduate midwives and the “profession needs to consider options for further support for midwives in their first year who are caring for higher risk women”.
Health Central contacted Lawton for a response to the follow-up study. Lawton described the Sadler research as a good study that used later and more complete data than was available in the years her team had looked at. She said the perinatal mortality rates the follow-up study found for first year midwives were very similar to her study but with the Sadler study concluding this was due to more high risk deliveries.
“We have a good maternity service in NZ with highly trained professionals but we can get better,” said Lawton. She said she agreed with the authors that there needed to be increased support for new midwives caring for high risk women. “We need to support our new midwives – that’s really important.”
Increased risk with lower caseload
The Sadler study found that how midwives were trained (i.e. whether they had first trained as nurses or were direct entry midwives) did not impact on perinatal mortality but it did find an increased risk of perinatal mortality among women cared for by midwives with lower caseloads.
It found an increase in risk of baby deaths among mothers cared for midwives with a caseload of 30 women or less per year (low caseload midwives) compared to midwives registering 51-80 women per year. There were no significant difference in risk between midwives with caseloads of 31-50 mothers or more than 80 mothers per year.
The authors said more research was needed to understand the association with low caseloads and high perinatal mortality risk. It said midwives with low caseloads can possibly fall into a number of categories including midwives just beginning or finishing their career, midwives providing primary care for women who are under specialist/secondary care in areas with no hospital midwives or providing care for high risk women who arrive at hospital having had no antenatal care.
Of the 85% of women cared for by community-based midwives during the period of the study (2008-2104), less than 10% were cared for by low caseload midwives.
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