Betsi Cadwaladr health board has suggested downgrading services at one of the area's three district hospitals due to a staffing shortage.
A legal challenge blocked the plan to downgrade maternity care at Glan Clwyd Hospital in Bodelwyddan, Denbighshire.
That prompted the consultation, which includes a series of public meetings.
Residents are unhappy with the plans, suggesting removing the service at hospitals like Wrexham Maelor and Ysbyty Gwynedd in Bangor will mean women having to travel further for care.
However, bosses said any changes would be temporary and are needed to ensure the safety of mothers and babies.
A dedicated health board website was launched on Monday to collate public reaction to the options, which also includes retaining all services.
Several public meetings are due to take place in September.

The technology and administration services provider, which employs 300 people in Northern Ireland, has won a government contract worth £500,000.
Its system is designed to help with the recording, planning and scheduling of staff.
The Passport Office has 2,500 employees working from 37 locations across the UK.
The platform will initially be used in Glasgow and then rolled out to the six other Passport Office locations throughout the UK.
Equiniti secured the deal though the government's G-Cloud procurement framework.
Nigel Farr, one of the company's directors, said: "Working patterns have changed dramatically over the last decade and far fewer businesses operate the stereotypical nine-to-five hours."
"Having a time and attendance system that is cloud-based is increasingly becoming essential in order to accommodate anything from flexible working or remote working to job sharing and hot-desking across locations," he added.
"Her Majesty's Passport Office has increased its flexibility and capability to respond to extreme external pressures which have a direct effect on its workforce requirements."

Benjamin Hyland-Ward faces nine counts of fraud by false representation in connection with selling tickets.
The 18-year-old, of Westfield Avenue South, Saltdean, East Sussex, is due to appear before Brighton Magistrates' Court on 24 March.
Hundreds of people were left ticket-less after paying to go to the event last September.
Sussex Police said the charges incorporated all of the reports of money being paid for but no tickets being given.
A consultation about plans which could see consultant-led maternity care withdrawn from a district hospital in north Wales has begun.
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Belfast-based firm Equiniti has been selected to provide a cloud-based system for the Passport Office.
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A teenager has been charged with selling fake tickets for last year's Bestival on the Isle of Wight.