All op can really do is try to tackle both possibilities:
1. One on one time (at least 30 min (with no baby) with older child each day doing child selected activity.
2. Ped appointment to rule out constipation or other physical issue

It might seem ridiculous, but she could be doing it because she likes how it feels. I can say this from personal experience. I started doing it during school, pretty much because I liked how it felt and getting away with it without being discovered. It is probably unlikely to be the reason your daughter is but it’s possible. If it is I think some counselling would be a good idea.

My parents didn’t do that for me, and they ignored the problem, so I kept doing it. In their defense I got good at hiding it, but I am sure counselling would have benefited me. I started doing it during some fairly tumultuous changes in my life, new school, moving, getting it trouble and others.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Pediatrician: they can let you know if there is a physical condition and can assess if there is abuse.

Ive heard this before but don't understand how abuse correlates to this does anyone know?

When a child has been sexually abused, sometimes the brain will deal with the overwhelm by shutting down signals from this whole area of the body.

OP, if you are still reading: assuming she is developmentally typical, third grade is VERY late for this problem to be showing up for the first time accompanied by denial this strong. It would be much more typical for her to be terribly embarrassed, but not actually sitting there in her own poop.

Something is wrong and you need a pediatrician’s help to figure it out. Get her into the doctor’s office.

Kids with encopresis often don't know they have pooped and don't smell it. It actually makes a lot of sense for this to appear 6 months after the sibling's arrival, as that would be time for the constipation to develop to the point of encopresis.

PP. The bold was true of my first grader. It is less plausible as a first-time problem in an 8-9 year old, sibling arrival or not.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Your immediate dismissal of this as just because of a baby being born is alarming. Of course that is a possibility. But it’s only a possibility.

How have you not talked to school counselor, pediatrician, therapist? You know this is a potential sign of child abuse, particularly sexual abuse, right?

What the hell is wrong with you that you are self-diagnosing this, worried about play dates, and not caring for your child? Wake the eff up and get PROFESSIONAL help. Get off of DCUM.

Even if this is just “only” adjustment to a sibling, that is not normal, and you need to get PROFESSIONAL HELP FOR YOUR CHILD.

This. It is really concerning that you are being so dismissive and ignoring your child's cries for help. Get her to a doctor and a psychologist immediately. WTF is wrong with you?

WTF is wrong with you? Why do so many posters on DCUM decide to post abusive sh$t like this?

DCUM can often be needlessly harsh. The OP of this post needed a wake up call, and I think posters mostly did a good job of providing that along with constructive advice. OP’s attitude to her child and inaction were disturbing.

The above goes well beyond "needlessly harsh". It is online bullying.

Are you new here?

I've been on DCUM way too long unfortunately

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Your immediate dismissal of this as just because of a baby being born is alarming. Of course that is a possibility. But it’s only a possibility.

How have you not talked to school counselor, pediatrician, therapist? You know this is a potential sign of child abuse, particularly sexual abuse, right?

What the hell is wrong with you that you are self-diagnosing this, worried about play dates, and not caring for your child? Wake the eff up and get PROFESSIONAL help. Get off of DCUM.

Even if this is just “only” adjustment to a sibling, that is not normal, and you need to get PROFESSIONAL HELP FOR YOUR CHILD.

This. It is really concerning that you are being so dismissive and ignoring your child's cries for help. Get her to a doctor and a psychologist immediately. WTF is wrong with you?

WTF is wrong with you? Why do so many posters on DCUM decide to post abusive sh$t like this?

OP is the abusive one here. The rest of us trying to get her to help her child.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Your immediate dismissal of this as just because of a baby being born is alarming. Of course that is a possibility. But it’s only a possibility.

How have you not talked to school counselor, pediatrician, therapist? You know this is a potential sign of child abuse, particularly sexual abuse, right?

What the hell is wrong with you that you are self-diagnosing this, worried about play dates, and not caring for your child? Wake the eff up and get PROFESSIONAL help. Get off of DCUM.

Even if this is just “only” adjustment to a sibling, that is not normal, and you need to get PROFESSIONAL HELP FOR YOUR CHILD.

This. It is really concerning that you are being so dismissive and ignoring your child's cries for help. Get her to a doctor and a psychologist immediately. WTF is wrong with you?

WTF is wrong with you? Why do so many posters on DCUM decide to post abusive sh$t like this?

DCUM can often be needlessly harsh. The OP of this post needed a wake up call, and I think posters mostly did a good job of providing that along with constructive advice. OP’s attitude to her child and inaction were disturbing.

The above goes well beyond "needlessly harsh". It is online bullying.

Are you new here?

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Your immediate dismissal of this as just because of a baby being born is alarming. Of course that is a possibility. But it’s only a possibility.

How have you not talked to school counselor, pediatrician, therapist? You know this is a potential sign of child abuse, particularly sexual abuse, right?

What the hell is wrong with you that you are self-diagnosing this, worried about play dates, and not caring for your child? Wake the eff up and get PROFESSIONAL help. Get off of DCUM.

Even if this is just “only” adjustment to a sibling, that is not normal, and you need to get PROFESSIONAL HELP FOR YOUR CHILD.

This. It is really concerning that you are being so dismissive and ignoring your child's cries for help. Get her to a doctor and a psychologist immediately. WTF is wrong with you?

WTF is wrong with you? Why do so many posters on DCUM decide to post abusive sh$t like this?

OP is the abusive one here. The rest of us trying to get her to help her child.

Anonymous wrote:I am extremely concerned about OP’s daughter. A third grader exhibiting this kind of behavior is screaming for help. Not a jealous child wanting attention because of a newborn. I hope the child gets the help she needs.

I'm concerned that you have a need to spend your time concern trolling online. What kind of life must you lead that drives you to do this?

I am extremely concerned about OP’s daughter. A third grader exhibiting this kind of behavior is screaming for help. Not a jealous child wanting attention because of a newborn. I hope the child gets the help she needs.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Also if she is 8 or 9, what is going on with the new baby situation? Usually by that age, the sibling is embracing being a mini mommy and helping with the baby. Is there more to this story? Do you feel like the baby is safe around her?

I had my second when DD was 6 and she was little mommy! I can't believe a child would be anything but, unless you are emotionally neglecting her and pushing her away.

Children are not all alike and just because she is female does not mean she is automatically nurturing. Firstborns often feel displaced by a new baby, understandably.

Male children also become helper or little daddys if they're nurtured properly. And sorry you're wrong - all children want to help their parents to gain approval - it's instinctual. It is also known that they will be jealous, so yeah, two things can happen at once. Did this just blow your mind? However, jealousy is more like being mean to the baby, not pooping oneself.

Anonymous wrote:

Anonymous wrote:Also if she is 8 or 9, what is going on with the new baby situation? Usually by that age, the sibling is embracing being a mini mommy and helping with the baby. Is there more to this story? Do you feel like the baby is safe around her?

I had my second when DD was 6 and she was little mommy! I can't believe a child would be anything but, unless you are emotionally neglecting her and pushing her away.

Children are not all alike and just because she is female does not mean she is automatically nurturing. Firstborns often feel displaced by a new baby, understandably.

Anonymous wrote:Also if she is 8 or 9, what is going on with the new baby situation? Usually by that age, the sibling is embracing being a mini mommy and helping with the baby. Is there more to this story? Do you feel like the baby is safe around her?

I had my second when DD was 6 and she was little mommy! I can't believe a child would be anything but, unless you are emotionally neglecting her and pushing her away.

Anonymous wrote:NO! This is a medical issue. You need to consult her pediatrician immediately.

You're a horrible parent for immediately thinking this poor child is doing it on purpose.

I hope you're a troll. Way to abuse your kid.

Agree.

The instinct to think it's because she wants attention tells me - GIVE HER F-ING ATTENTION THEN. Also, if you think she's doing it on purpose - you're complicit if it's actually abuse that's causing it.