What did you do with SD/SS?
BM lives very close to DH and I, on our way to the hospital actually. They have 50/50 through the week custody - we have SD 3 nights and BM has her 4. What kind of plans did you all have for your SD/SS if you went into labor while you had them? SD is 5 and I don't really have plans for her to be at the hospital during labor or delivery. She can come after LO gets here to see him, but I don't see the need for her to be there since labor can take minutes or hours (probably hours since this is my first). I guess I just need guidance and how to talk to DH about this from every aspect. He hasn't really said anything and hasn't talked to BM about it. Also, did any of your custodies change a little while you were home recovering? DH may not be able to be home with me immediately after LO arrives and I doubt very seriously I'll want to be learning how to take care of a newborn and chase SD around? Help. 
Re: What did you do with SD/SS?
We had SS when my water broke - actually my water broke at work as I was leaving to pick SS up from school.
I called my Mom to come meet us at the house and watch SS. We told SS (he was almost 6) that we had a doctor's appointment for the baby.
As soon as we knew that I was staying in the hospital and we would have the baby within 24 hours - we called BM and gave her the option of picking up SS or leaving him with my Mom - she went and picked him up.
We called SS and told him that we were going to have the baby and I had to stay in the hospital. We told him his Mom was coming to get him and that he would be the first person we would call when the baby was born.
Baby was born at 7:23 AM - we called SS and BM brought him to the hospital sometime around 11:00 I think. SS stayed at the hospital until 7:00 and then DH took him back to BM and then SS came again the next day for the whole day and DH took him back to BM at 7:00.
We normally do not have a great relationship with BM - but it all worked out and I couldn't have asked for it to go any smoother!
I forgot to answer your 2nd part.
After the initial weekend I had the baby and I was in the hospital - we didn't change any custody time. We also have 50% and SS was 5 (almost 6).
SS came over and I had him and an infant. I BF with no issues - used the TV as a babysitter a little more than normal - and my neighbors helped out a lot. All the neighborhood kids usually play in my backyard bit for the first 2 months or so after the baby was born, the neighbors would invite SS over to their house to play - it usually gave me an hour or two to nap each day!
Honestly - SS could aggravate me since I was exhausted and sore (I had a C-section) but he was also a big help.
Lots of pre-prepared foods - easy tot cook stuff. Lots of movies and cartoons - and I would try to spend time playing with SS when baby was napping or in the swing.
It is very, very manageable and allow the children to bond!
This is going to be one of those things that's different for everyone. In my situation, I'm the CP and XH is across the country.
Fortunately, DS was in preschool when I went into labor with DD. My parents live nearby, so while DH & my mom went to the hospital with me, my dad picked up DS, took him to the park for awhile, and then brought him to the hospital to wait for DD.
Had I gone into labor in the middle of the night, DH & DS would have come to the hospital with me until my parents could come help with DS.
You just need to think through what is best for your family. Are there grandparents around who can help get your SD to the hospital after your baby is born? Do you have a good/civil relationship with BM?
I did fine with an infant and a 5-yo DS at home. In fact, the night I came home from the hospital I had to bake cupcakes for DS's birthday. DH stayed home with me for 2 days and then went back to work; and DS was in preschool full time. But I think you'll be REALLY tired those first few days. If your DH won't be home, can a grandparent come give you a hand?
My SD is 5 and will get very bored, which is the only reason I don't want her there the whole time. If she were older, I'd be fine with her being there.
She's been the only child and only grandchild on both sides for 5 years. My SIL just had a baby a few weeks ago and now I'm due. She's shown some jealousy with all that's been going on - nursery, lots of gifts, everybody wants to talk about the baby and the belly. She even made a comment the other day that she wishes she was a baby again so she could be in the baby room at her daycare. I don't really think it's because of daycare, but... Her jealousy is a whole separate post.
DH's parents both live close and that was our alternate plan if she didn't go to BM's was to take her to my FIL's or have her at the hospital for a few and let FIL come and get her and take her back home with him.
My mom will be here for about 2 weeks after LO is born specifically to help me out with LO, but she's kinda odd about SD. Not that she doesn't love her to pieces, just thinks that sometimes I watch her and keep her more than her own parents. I can't help DH's work schedule though and we're not changing times because of it.
At the time we had SS on Tuesday nights which happened to be when I was in labor so we switched Tuesday for Thursday. We had plans for SS to come see DD after she was born but she was born in the middle of the night on a school night so BM brought him over to the house after school on Wednesday.
Our custody didn't change at all immediately afterwards. I was fortunate that while DH had to go back to work on Thursday and Friday after she was born, he was then able to take 3 weeks off. Like I said, we kept him overnight on Thursday. DH picked him up and my mom took him to school the next morning.
I'd definitely tell your DH that if you are the one typically responsible for drop-off/pick-up that he'll need to do it or you'll need to make other arrangements. I had a fairly normal L&D and I didn't feel like driving anywhere for like a week. I would also keep the custody arrangement as close to the same as possible, it will help your SD feel like a part of the family.
That is kind of young so try to line up someone to take care of her and then bring her after the baby comes. If she doesn't go to BM's obviously. As far as the jealousy...that is very normal. I would try to involve her in as much as you can..even go out and buy her a big sister gift. Talk up how much fun it is to a big sister. It's not going to solve the problems overnight but it will help. This is a huge change for kids that age to understand/accept so just be patient with her. It will get better.
You mentioned that she is in daycare, would she continue with that after the baby is born? 3 nights a week, I can't imagine would be too much to manage. I wouldn't take SD less after the baby is born, I think that may send the wrong message and she would feel left out or hurt?? GL
We made plans for if we had SS and I went into labor. I had a friend lined up to stay with him until his mom could get him. Turns out we didn't need that, but yes you need to figure it out just like if you would for a kid you had full custody of.
We have SS every weekend. I had DD on a Wednesday but didn't leave the hospital until Sunday, so we didn't have him that weekend. But he was there the next weekend. I had DS on a Monday and was home by Wednesday and SS came for the weekend.
If your DH won't be there the first time and your family or friends can't help, then you need to hire a sitter or mother's helper.
And for the jealousy thing, you really need to work on that these last few weeks. Push the big sister angle. How she's going to be so important to the baby, this is HER baby bro (getting her to have a sense of ownership about the baby is HUGE), when the baby gets older she can teach him how to put his shoes on and do big kid stuff. Point out all the super cool stuff she can do that the baby can't do (run, play with toys, watch tv, talk). And go buy a present from the baby to her and ask your mom to do the same (even if you have to buy the present from your mom to her).