Pooping in Pants 3.5 Year Old

Exactly, have your daughter just say "sorry buddy, next time we will get it in the potty." Regressions happen, they turn into big deals only when you make them a big deal. Otherwise they last a few days or weeks and then things go back to normal.

Exactly as you said.

Also, make sure the parents do not punish him for it.
Or he might resent the baby.

Remember: he is a child. He is only 3.5 years old. Children, make mistakes. They have potty accidents and pee accidents. THAT is what childhood is. NO child, is 100% perfect about it. And he has ONLY been potty trained for 6 months. That is not long.

Tell her: That ALL of my daughter's Teachers, from Preschool to Kindergarten to 1st grade... ALL SAID UNANIMOUSLY, that kids these ages.. .have accidents. They treat the child in a kind manner about it. AND they make no big deal about it. It is, childhood. They are young.

And night time dryness, is not something that occurs, until even 7 years old. So please.... understand, that night time dryness has nothing to do with day time pottying. Night time is about the body's PHYSIOLOGICAL development of the organs... the brain/bladder/myelin nerve sheath development. It is not, per the age of the child. It is a physiological, maturity of the organs. Until that happens, a child sleeps in night time diapers. It is normal.
My son is 5 and still wet at night. Still has night time diapers. The pediatrician says it is normal.
My daughter was the same way. She even still had accidents at night, at 7 years old. Normal.
Normal.
Normal.

When I was pregnant with my 2nd child, I spent my entire pregnancy on my eldest child... getting HER prepped for her little brother. She'd hug my tummy, sing to her brother in my tummy, nap with me, and we'd take photos of her WITH my growing belly, all the time. She already LOVED her baby brother, even if he was still in my tummy. She had bonded with him, already. Thus, when baby brother came home, she was already, adjusted. I did not wait... until after the baby came home, to then get her used to it. I started "helping" with transitioning her to her baby brother, WHILE I was pregnant. She even came with me to my prenatal appointments... which my OB/GYN encouraged... and he'd even let her put the Doppler heart monitor on my tummy.
It helped a ton.

However, when I did have my son.... for a short time, my daughter also started to have potty accidents. (she was 4 years old then). We and her Teacher, helped her through it. Never scolding or making her embarrassed about it. It was her, being a little child, adjusting her to new baby brother and me, being busier.
We talked with her, and consoled her, instead. And comforted her. Then she was fine.

its typical when a new baby is coming or came. just keep it up. my daughter thrived with a sticker chart.

S.H said it best. Accidents happen, as does regression, especially when there is a major change in their lives. I would encourage your daughter to keep some kind of reward for "accident free" days, much like i'm sure she did when he was originally training.

I did something similar with all my older children whenever I became pregnant again. I didn't want to force the new addition into their hearts, but I also wanted them to be ready for him. Frequent (3x a week or so) small activities to encourage bonding is plenty, even if its something small like having him pick out a new outfit for himself AND his new sibling. It will help him see things as less of a change, and more of a natural progression, and help him to realize that he's not going to be forgotten once the new baby arrives (we obviously know this, but many kids fear that they will be "replaced" by a new baby).

Best of luck to your family, and a big congratulations to your daughter!

My daughter is now eleven, but I remember her going through a stage like this around that age and the doctor told us she very well may be constipated. So we tried myralax, prune juice, etc. and all was good again. Good luck!

My son JUST went thru this last month (he would have been . . . 45months). Potty trained for at least a year, accident free for almost a year. Then boom, pooped in his pants one day - I just reminded him that poop goes in the potty, cleaned him up not expecting it to happen again. The next day, same thing, except that I secretly tell my husband that we might have a serious problem. It hasn't happened since, but I can't figure out why it happened. No changes, no new baby, no new anything. *shrugs*