The Royal College of Midwives (RCM) accused the government of doing ‘far too little’ to prevent what it calls a recruitment and retention crisis in the profession.
NHS Digital figures show the equivalent of 114.4 full-time midwives were working at the hospital in December 2021 - 3.9 fewer than 118.3 at the same point in 2020.
Gill Walton, chief executive of the RCM, a trade union for midwives, said: “While we welcome attempts to train and recruit new midwives, this government is doing nothing to stop the experienced and qualified ones from leaving.
“At the same time as demands on services and the pressures on maternity staff are rising, staff numbers are going down.
“Despite the often-heroic work of midwives and others to try to plug the gaps, this is putting the quality of care and the safety of women and babies at risk.
“Lots of factors will have contributed to this - if the theory is right then some midwives who had delayed their departure have now decided to go ahead with it.
“Pay will also have been a big factor for many, with the government dragging its feet for months before eventually botching the recent pay announcement.
“On the issue of the midwifery shortage, it is worth noting - as we look at the workforce numbers - that it has been 11 years since then-Conservative leader David Cameron promised as the 2010 general election approached to boost midwife numbers by 3,000.
“The following year, in 2011, the election pledge had already been abandoned.
“Now, more than a decade on, the Conservatives are still yet to boost midwife numbers by this much, after more than a decade in power.”
Across England, there were the equivalent of 337 fewer full-time midwives working for the NHS in December 2021 than at the same point in 2020.
It means there are now 22,192 full-time midwives working on maternity wards nationally.
NHS England announced a recruitment drive for maternity staff as a result, promising £95m to be spent on recruiting 1,200 midwives and 100 obstetricians.
A spokesperson added: “We recognise that we have more to do to bolster our maternity workforce to ensure that we can provide the safest possible care for women and their babies.”