An optional toggle to a hospital zone, if enabled, it would impact the behavior of dwarven mothers.
With a hospital zone defined with a maternity ward, the following would happen.
If a dwarven mother comes due to give birth, she will still interrupt her current job, but instead of giving birth on the spot, she will make her way to the hospital zone. If there is an empty bed she would claim it, stay there for awhile before finally giving birth.
Giving birth in a hospital zone in a bed would generate a happy thought.
A new wood-only item would be available for production at a carpenter's shop: The Crib
If a crib is placed in a hospital zone, newborns will be placed in it rather than carried around by their mothers.
Newborns in a crib must be given food and water by hospital workers in the same way that injured dwarves are. The main benefit being that the mother does not endanger her infant by carrying them around all the time, allowing them to more safely serve in the military. That said, you must ensure that there are nurses in the hospital who have access to food and water or the infant will starve or die of thirst.
Goblin snatchers are naturally attracted to cribs and will try to steal children out of them.
Cribs can also be placed in bedrooms. If a mother is carrying her infant and goes to their room to sleep, they'll deposit their infant in the crib first. This doesn't serve any huge purpose, though the crib will add to the room's value in the same way that any other furniture does.
Babies who grow old enough to become children will automatically leave their cribs and act normally.
If your fort doesn't have a maternity ward, dwarven mothers will act exactly the same as they do now, giving birth in the field and carrying their children.
If there are no available beds in a hospital when a mother shows up to give birth, she'll just give birth on the floor but receive a bad thought.
If there are no open cribs in a maternity ward, the mother will still carry the infant around with them.
Stretch suggestion:
I'm not sure if gender-specific jobs are possible, but if so, make a new skill: Wet Nurse
The 'skill' cannot be used untrained. Males cannot gain xp in this skill.
The act of giving birth gives wet nurse xp to the mother, enough to give at least one level in this skill, even if she doesn't have the labor enabled.
A wet nurse enabled labor will cause the nurse to perform the following jobs.
If there are infants in the hospital zone who are hungry or thirsty, they will feed them. Doing so satisfies both hunger and thirst of the infant but does not require any food or fresh water. The mother will gain more skill in wet-nurse every time she performs this job. Each time this job is performed, the mother the father and the infant all get good thoughts about "Urist McWetnurse took good care of my baby/me". The strength of the happy thought would be tied to the skill level of the wet nurse. The wet-nurse will gain happy/unhappy thoughts depending on their personality, with a preference for caring for others generating happy thoughts.
If there are any infants not being carried by their mothers, (Mother died, or a failed goblin snatcher attack) a wet-nurse will attempt to bring them to a hospital zone and put them in cribs. If infants need to be moved to another location (due to burrow orders) wet-nurses will act as infant haulers as needed.
Migrant women who come to the fort with a child will have a random skill level in wet-nurse.