How much time to take off for Maternity leave?

Hi everyone! We are currently 9 weeks along with #5... Yes #5 LOL. My own children are 15, 13, 10 and 16 months (second marriage for me!). I live in Durham Region, Ontario and have 4 full time toddlers in my care between 11-17 months of age.
Since this is #5 for, I am beginning to show already and am hiding it pretty well... for now. We already had an ultrasound last week all looks good! However, I want to wait a few more weeks until the next ultrasound and rest of the other testing is done before announcing to my dc parents.
I am wondering how much time off should I take? My husband will be taking leave (his work thankfully tops up EI premiums so he will be making the same amount) and my mother in law will be helping out when baby comes. I am just not sure, how much time to take off. I don't want to take on more than I can handle. I have a history of PPD. I will have my older 3 in school full time all day (gone 8:45-4:00 pretty much) and my youngest who will be 23 months when baby comes. When this baby comes we will also be starting toilet training...
I was thinking 1 week possibly 2. Now I am thinking longer, perhaps a month? I know that 1 family will not be family as they tell me repeatedly they don't have any family or any other back up around (not my issue!).
What has everyone else taken and I would love all your suggestions! I do have some time to ponder this so want to have all my ducks in a row before I announce in a few weeks.
Thanks in advance!

Well, I would definitely take at least a few weeks off. But, as for your return.....have you thought about hiring a helper for just a few weeks? If you hired someone at minimum wage for 8 hours a day that is about $85 a day. If you have four dckids at an average of $40 a day (just figuring out at that rate. Not sure exactly what you charge) that is still about $120 a day you will make. Even if you could just have a helper for the 6 busiest hours of your day it would help.

Looking at the world from your own two year olds eyes you might also want to disrupt their life as little as possible which means not a great deal of time off or your child will go from being entertained by all their friends and a set routine to just "hanging around" while everyone rushes to do baby things or sits to rest and does nothing - not fun for a toddler and that is more likely to lead to issues for them. You said hubby would be there and mil part of the time.

Only you can decide really how much time you think you need. Is it possible that you will have less ppd issues if there are more things needing your attention or does all the demands from extra people make it worse? That may for sure influence your decision.

Anything more than a couple weeks to a month and expect children to get used to their new temporary daycare and plan to stay there instead of returning. Which is another option - to actually close when your baby is born and then when you are feeling better and got the new routine set you can advertise and start again.

Thanks! At first I was thinking oh I will just take 1 week but Playfelt you are right... I worry about my toddler becoming used to being entertained and then having to start the whole transitioning him to get used to kids coming to our home for daycare again. I was going back and forth with closing for 6 months then re opening with all new families but then there is all that mess of interviewing... bleh!
So I think I will get my plan in place and take 2 weeks. I will put out a notice in the next couple of weeks giving the news, asking for updated emergency contacts (I went into labour at 35 weeks with my youngest so its quite possible that may happen again). I will give the option for my Doctor's appts (thankfully now its with my GP who has evening appts but soon enough will be with the OB who is only 9-4) if they want me to book them during naps and my MIL can stay with them while they sleep OR if they want me to have them pick up early.
I will also mention that my husband will be home to assist me but I will be doing all the main things such as the programming, diaper changes, etc.
So much to think about!!! Just want to make sure I have it all put together before I break the news.
Did I miss anything?

I have 5 also !!!!! Congrats !!!!

Congratulations!
I took 6 weeks off and all of my families returned. Phew! I found what made it easier for them and me was to make all of my appointments with my doctor at the same time on the same day of the week. So I sent the schedule to them by email when I was about 15 weeks pregnant, and then they could make arrangements to pick up early or agree to leave their child in the care of my husband. My blood work and ultrasound appointments were always on Saturdays to limit the amount of time I had to take off. I wouldn't ask your families for too much input just incase they have opposing views and then you're left disagreeing with someone. I hope that makes sense:o
Having a baby is wonderful so don't apologize for that. The more time you can take off, the better. Your body and your baby deserve a bit of downtown as you all adjust. If possible! Good luck.