There has been a 35% drop in the number of applicants to midwifery courses since 2013, figures show.
The Royal College of Midwives (RCM), which analysed the latest Ucas data for England, said the biggest reduction was in those aged 21 or over.
In 2013, more than 12,000 people aged over 21 applied for a midwifery course in England, but by 2017 that figure had dropped to just 6,700 - a decrease of 45%.
The RCM said the abolition of the midwife bursary last August was to blame, although numbers have been falling steadily since 2013.
Professional policy adviser Gabrielle Bourke said the NHS in England is 3,500 midwives short of what is needed to deliver safe, high-quality care.
She added: "We are not entirely surprised by these figures as the RCM has previously raised concerns about how less attractive midwifery as a profession was becoming particularly since the midwifery bursary was abolished and tuition fees were introduced in August 2017.
"This coupled with already younger midwives leaving the profession due to workforce pressures such as understaffing causing burnout, in addition to seven years of NHS pay restraint, have certainly been factors that have deterred students from applying for midwifery courses in England.
"It's disappointing to see the drop in applications from those aged 21 and older.
"We know that many of those who have previously chosen careers in midwifery have been older students, often women with children inspired by the care they received while pregnant choosing to become midwives.
"Also, currently a large proportion of the midwifery student base hold other degrees or educational qualifications relevant to healthcare and these are the type of people the NHS so badly needs and we should be doing everything we can to attract and retain the brightest and best students to midwifery."
She added that the RCM welcomes the recent announcement by Health and Social Secretary Jeremy Hunt to train more than 3,000 midwives over the next four years.
A Department of Health and Social Care spokesperson said: "Our priority is getting more midwives working in our NHS, which is why we increased the number of midwifery training places available by 25%, allowing more people to study midwifery than ever before.
"Any decrease in the number of applications must be seen in the context of this significant increase in the number of places available - and places remain oversubscribed."