We live in Columbus, Ohio. Our son turne
For reference only. Not medical advice.
Question
We live in Columbus, Ohio. Our son turned 3 years old last month.
He was fully daytime potty trained for 5 months with zero daytime accidents.
Three weeks ago, his baby sister was born. Since bringing her home, he has started wetting his pants 2 to 3 times a day, demanding to wear diapers again, and asking for a baby bottle.
He has not lost any other skills—his speech, motor running/jumping, and imaginative play are thriving.
Could you help us understand this:
- State the age basis (3-year / 36-month checklist) and explain what CDC 75%+ milestones mean vs behavioral regression around a major life transition.
- How to distinguish common temporary emotional regression from a true neurological "lost skill" that requires pediatric evaluation?
- What is our one dated next step table for home and the pediatrician?
- End with one specific clarifying question that changes how you read this.
Answer
Age basis: CDC 3-year (36-month) card. Today is September 18, 2026. You're in Columbus, Ohio, so the US / AAP row applies for the well-child schedule.
1. What the 75%+ card says vs what you're seeing
The CDC3-year list is what most children this age do. Staying dry by day is not on the card — that timing varies widely and is not one of the 75%+ milestones at 3. What the card does list, and what you say your son is still doing:
- Calms down within ~10 minutes after you leave
- Notices other children and joins them to play
- Talks with you in two or more back-and-forth exchanges
- Asks "who," "what," "where," or "why" questions
- Says his first name when asked
- Says what action is happening in a picture
- Draws a circle when you show him how
- Avoids hot objects after a warning
- Strings beads or macaroni, puts on some clothes, uses a fork
He is hitting every domain on the card. So the regression you are seeing is not a "didn't reach the milestone" gap — it's a previously-mastered behavior that has slipped during a major life transition.
Source: https://www.cdc.gov/act-early/milestones/3-years.html (accessed 2026-09-02)
2. Emotional regression vs a true "lost skill"
- True lost skill. A child used to do something and has stopped doing it — across settings, not only at home, with no clear trigger. Examples that move a parent to call today: stops talking, stops using his hands to feed himself, stops running, stops responding to his name, stops pretending. *That* kind of change is what opens a same-day or soon visit.
- Common emotional regression around a new baby. everting to baby behaviors (bottle, diapers, baby talk) is well-described in 3-year-olds. The child reaches back to the same stage as the new baby. Potty is one of the first skills to slip and one of the last to come back.
- The two signals that change the read:
- The regression spreads beyond potty/bottle to other domains (speech, motor, social play, sleep, appetite), or
- It's still happening daily ~2 months after the baby came home with no improvement.
You told me speech, motor, and imaginative play are intact — that points to the second pattern, not the first.
3. One dated next step
| When | What to do |
|---|---|
| Today, Sept 18, 2026 | Write it down: baby came home around Aug 28, 2026; potty started slipping ~3 weeks ago; speech, motor, imaginative play all intact. |
| This week | No punishment or shaming for the wetting. Keep him in underwear or training pants; offer the potty on his old schedule; name the feeling ("you want to be a baby too — that's okay"). Set aside 10–15 minutes/day as big-brother time with you, no baby in the room. |
| At his next well-child visit (or book one if none is on the calendar) | Bring the note. AAP / CDC US schedule: general developmental screening at 9, 18, and 30 months, and "whenever concerned." The 30-month screen was the last scheduled one before 3. A formal screen (e.g., ASQ-3) returns a pass / monitor / refer — not a diagnosis. |
Source for US schedule: https://www.cdc.gov/act-early/about/developmental-monitoring-and-screening.html (accessed 2026-09-02)
Limits
I don't diagnose or run a screening. If speech, motor, social play, sleep, or appetite change — or the potty regression is still happening daily 2 months from now with no improvement — that moves the read from "common new-sibling regression" toward "ask the pediatrician sooner."
How are his sleep and appetite over these same 3 weeks — unchanged, or any change there?