Ethical question about returning to work

Sascha3

I don't intend on returning to work after my maternity leave is up (I will have 3 months).  A major part of this is that my work hours are so irregular, I either open from 9 to 6, or I close from 3 to midnight.  Many times I close, then open the next morning.  I can't imagine getting home close to one, then going back to work after trying to get a few ours sleep.  The 45 hour work week and irregular schedule is just too much.  My employer does not allow part time, and it would be unfair to other staff for me to not have to work both shifts.

I hope to stay home for a couple years, as I plan to get pregnant after 9 months or so, due to my age (I will be 40) and not wanting to wait too long.  But if it ends up not being financially comfortable, I would like to return to something with shorter hours and a more regular schedule.

The dilemma I am having is when to tell my employer.  The thing is that I am afraid to just quit before the birth of the baby because I don't want to fully commit to quitting.  I am a worrier....what if my husband loses his job?  what if there are health issues and I need the extra insurance?  what if something major and unforeseen happens where I really need the second income?

I would just feel much more secure quitting when the time comes so I know exactly where things stand in life.  I would hate to make a huge mistake and leave a very well paying job if it ends up that I would need to stay.

How unethical is it to decide during my maternity leave?  (I do not get paid for maternity leave...it would just be the insurance and to hold my position.)