Staff at Mid Yorkshire Hospitals NHS Trust and Dewsbury and Batley MP Jo Cox celebrated the official start to construction of the centre on Friday.
The new unit is part of a shake-up of services at the trust which will see Dewsbury lose its consultant-led maternity facility.
From next summer women with complex births which need a consultant presence will go to Pinderfields Hospital in Wakefield.
Women expected to have “low risk” births will be looked after at the new unit at in the Ridings building at Dewsbury, which will have six en-suite birthing rooms, including two with their own birthing pools.
Gill Pownall, head of nursing and midwifery in women’s services at Mid Yorkshire, said: “This is an exciting time for maternity services at Mid Yorkshire.
“We are working closely with the local community and midwives to create a calm, peaceful, safe environment for women to birth their babies. We are thrilled that the long awaited countdown has begun.”
Mid Yorkshire said centralising consultant-led births at Pinderfields would make births safer.
Using midwife-led units (MLUs) for pregnancies classed as low risk was recommended by the National Institute for Health and Care Excellence.
But fears were raised that women who have complications during childbirth could be at risk after Dewsbury loses its consultant presence.
Jo Cox MP was worried about women in labour and premature babies having to be transferred to Pinderfields by ambulance.
Speaking after Friday’s event, she said: “I am delighted with the trust’s investment in Dewsbury and District Hospital and hope this guarantees a maternity unit at our hospital for the long-term.
“I am a supporter of midwife-led units and the excellent care midwives give mums-to-be but I know this change is something that concerns a lot of local people, not least because of the wider implications for the future of our hospital but also because of the time, distance and complication in getting to a consultant at Pinderfields.”