If your recently-trained toddler or preschooler has started having accidents again since the baby arrived, you are in one of the most common patterns in early parenting, and one that almost always resolves on its own within a few weeks if you don't add pressure to it.

Here's what's happening, what to do, and what to skip.

Why it happens

There are three overlapping reasons a newly-trained child regresses when a sibling arrives:

Attention economics. Before the baby, they were the primary object of adult attention. Now, adult attention is split, sometimes very unevenly, especially in the first weeks. Having accidents is one of a small number of ways a young child can reliably capture a parent's full focus. This isn't calculated manipulation. It's a low-grade nervous-system response.

General regression is universal. In every domain, sleep, eating, language, independence, kids commonly regress a bit when a sibling arrives. Toilet skills are no exception. Regression is the body's way of asking to be small again for a stretch.

The bathroom lost priority. Before the baby, "let's go potty" happened at natural pauses in the day. Now, the parent might be nursing, changing, or holding the baby when the child says they need to go. A few missed windows, and the habit weakens.

None of these are moral failings. They are predictable dynamics in a family that just got bigger. Understanding them helps you not add fuel to them.

What to do (very short list)

Treat accidents like they never happened. Same tone, same words, no expressions. "That's okay, let's clean up." Same phrase every time. Predictable and low-emotional-weight.

Restart the routine in a low-key way. Not "we're going back to basics because this is a problem." Just quietly resuming: "Let's go potty before we go outside." "Let's try before nap." Not more prompts than before, same rhythm as before, just re-installed.

Book one-on-one time that isn't about the toilet. Ten to fifteen minutes a day of just your older child and one parent, doing something they choose. This is the actual fix, and it works surprisingly fast. Attention regressions dissolve when the child feels reliably attended to for reasons unrelated to what their body did.

Wait it out. Most sibling-related regression resolves in 2–4 weeks with no active intervention beyond calm neutrality. The mistake is escalating during this window. That's what turns a two-week regression into a three-month one.

What to skip

Don't punish. Not sighs, not "come on you know how to do this," not time-outs. The accident is not the point. Anxiety and identity shifts are the point.

Don't reward the return to using the potty. Adding stickers or treats reinforces that this was a Big Deal. It's not. Neutral is the message.

Don't ask them if they went every twenty minutes. Frequency of asking amplifies the tension. You didn't ask before. Don't ask more now.

Don't compare them to the baby. "You don't want to be like the baby, do you?", this is very common and it usually backfires. The child either doubles down on wanting to be like the baby (because the baby seems to get the attention), or absorbs the comparison as evidence that their body is a source of adult disappointment.

Don't talk about the regression in front of them. Even in adult conversations they seem to be ignoring, they hear this.

Timeline expectations

For most families with a straightforward sibling-arrival regression:

Days 1–7 after baby arrives: Accidents likely. Everyone is exhausted. Just clean up and move on.
Weeks 2–3: Pattern usually starts to shift. Accidents decrease. Not linear, but the trend line is downward.
Weeks 4–6: Most kids are back to their previous baseline.
Weeks 6+ and still regressing: Something else is likely going on. See below.

Some families see faster resolution. Some see slower. The direction matters more than the pace.

When to worry

Reach out to your pediatrician if:

Regression persists past 6 weeks with no improvement trend
Your child was struggling with constipation before the baby arrived, and now bowel movements are painful or infrequent
They're actively hiding to try to poop
They start showing signs of holding stool (crossing legs, tiptoeing, tummy pain)
Underwear soiling continues, especially with any signs of leakage that don't feel like typical accidents

Any of these can be signs that constipation has entered the picture. Constipation on top of a sibling regression is one of the pathways to a longer-term stuck routine, and catching it early makes a big difference. Our Childhood Constipation guide walks through what to watch for. If accidents are starting to look like leaks around a blockage rather than misses to the toilet, that's specifically an encopresis pattern, see What Is Encopresis?.

What tends to make it worse

Even with the best intentions, some common moves prolong sibling regression:

Overhauling the routine. Introducing new bathroom prompts, new rewards, new rules. This signals to the child that something is broken. Same routine as before is what carries the message that they'll be okay.
Talking to other adults about the regression when the child is in earshot. Kids absorb everything about how their body is being discussed.
Getting into a discipline-and-consequence loop. Once discipline becomes part of the picture, the child's relationship to the toilet gets tangled up with their relationship to your approval, which is exactly the tangle you're trying to avoid.
Adding more prompts to compensate. Reminders and prompts amplify pressure. If you didn't prompt hourly before, don't prompt hourly now.

The bigger picture

Sibling-related regression is short-term, predictable, and mostly self-resolving. What you do during the regression matters less for the immediate accidents and more for what your child internalizes about their body and their new family shape.

If the message they take away is "my body is a problem right now," that message can persist. If the message they take away is "my body is figuring things out, and my parents are still here in the same way they always were," that message also persists.

The second message is the one that helps.

For families where routines have gotten stuck and need to be re-installed in a low-pressure way, Quiet Sit is what we built for running the daily sit piece, same tone every day, no scores, no pressure, so the routine can be background in a household that already has plenty going on.