Your kid needs glasses. The bill is $180. You text your ex a photo of the receipt, and... nothing. No reply. Or worse: "I never agreed to that." If you've been through this, you already know the sinking feeling. Medical expenses for kids after divorce shouldn't require a negotiation every single time. But for a lot of co-parents, they do.

I'm a divorced dad of three in Montreal, and I've lived this exact scenario more times than I'd like to admit. So I dug into the legal side of things, talked to other parents in r/coparenting and r/Custody, and put together what I wish someone had told me two years ago.

What Counts as a "Medical Expense" in a Custody Agreement?

Most court orders and separation agreements split medical expenses into two buckets: ordinary and extraordinary. Ordinary medical costs are things like routine checkups, basic prescriptions, over-the-counter medicine, and annual dental cleanings. These are typically covered by the parent who has the child at the time, or folded into child support.

Extraordinary medical expenses are where the fights happen. We're talking orthodontics ($3,000-$7,000 for braces in 2026), therapy sessions ($120-$200 per visit without insurance), surgery co-pays, prescription glasses, allergy treatments, and specialist visits. In most U.S. states and Canadian provinces, these costs get split between parents based on income or a fixed percentage spelled out in the court order.

The distinction matters because your co-parent might technically be right that they don't owe half of a $12 bottle of children's Tylenol. But that $400 eye exam and glasses? That's almost certainly a shared expense.

Does Your Court Order Require Both Parents to Pay?

Here's the part most people skip: go read your actual court order or separation agreement. Right now. The language in that document controls everything.

In the United States, most family court orders include a clause about "unreimbursed medical expenses" or "extraordinary medical costs." The U.S. Department of Health & Human Services tracks child support guidelines by state, and nearly every state requires both parents to share medical costs beyond what insurance covers. The split varies: some states mandate 50/50, others use a pro-rata calculation based on each parent's gross income.

In Canada, the Federal Child Support Guidelines under Section 7 specifically list medical and dental expenses as "special or extraordinary expenses" that both parents share proportionally. This includes dental work, orthodontics, counselling, and any medical treatment not covered by provincial health insurance.

What If the Order Is Vague?

Some agreements say something generic like "parents shall share extraordinary expenses." No percentages. No definitions. This is where problems start.

If your order doesn't define what counts as extraordinary or how the split works, you've got two options:

File a motion to modify the order with clearer language (costs $200-$500 in filing fees, sometimes more with a lawyer)
Document everything and request reimbursement formally, building a paper trail for court if needed

Option 2 is where most of us start. And honestly, it's where a good tracking system pays for itself.

What to Do When Your Co-Parent Refuses to Pay Medical Bills

When your co-parent won't split medical expenses, resist the urge to fire off an angry text at 11 PM. (I've done this. It doesn't help.) Here's a step-by-step approach that actually holds up if things go to court.

1. Send Written Notice Before the Appointment

If the expense is planned (orthodontist consultation, allergy testing, therapy), text or email your co-parent beforehand. Include the date, the provider, the estimated cost, and why it's needed. "Dr. Patel recommended allergy testing for Maya. Appointment is March 12. Estimated cost after insurance: $280. Per our agreement, your share would be $140."

This creates a clear record that they were informed and had a chance to object.

2. Get the Receipt and Send It Promptly

After the appointment, send the receipt within 48 hours. Don't wait three weeks and then dump five receipts at once. Courts look at timeliness.

3. Follow Up in Writing

If they don't respond within a reasonable time (7-14 days), send one polite follow-up. "Just checking in on the $140 for Maya's allergy testing. Let me know if you'd like to discuss." Screenshot everything.

4. Log It in a Shared Expense Tracker

This is where having a system saves you. When every medical expense is logged with the date, amount, category, and receipt photo, you're not scrambling to reconstruct six months of purchases if you need to go back to court. I've written about why a tracker beats a spreadsheet and the difference is massive when it comes to medical expenses specifically.

5. File a Contempt Motion If Necessary

If your co-parent consistently ignores court-ordered obligations, you can file a motion for contempt of court. This isn't free (expect $300-$1,000+ depending on your state and whether you hire an attorney), but judges take it seriously. Especially when you show up with documented proof of every request, every receipt, and every ignored message.

My Experience: When Every Expense Becomes a Negotiation

I'll be straight with you: the medical stuff was never the biggest dollar amount in my co-parenting expenses. My oldest son's judo costs $130/month and private school was $260 for two kids. But medical expenses hit differently because you can't just say "no" to them. Your kid needs glasses. Your kid has a toothache. There's no "let me think about it."

When my son got injured at judo, my ex said she wouldn't contribute to any extracurricular expenses going forward. Not just judo, but swimming, everything. She told me, "I'm not going to spend any money on activities." And the medical bills from the injury itself? Those became my problem too. I paid for the doctor visits, the follow-up appointments, all of it. Because what's the alternative? Your kid is hurt and you're going to wait for a text back before going to the clinic?

Before I built any kind of system, we were just sending receipts back and forth on WhatsApp. I'd buy something, send the receipt, she'd ask "what's this for," I'd explain, and then we'd argue about whether it was necessary. Medical expenses were the worst because there's real urgency. You can't postpone a dentist visit for two weeks while you negotiate who pays. I realized I was often just paying and not even asking for her half because the argument wasn't worth the $60. But those $60 charges add up. When I started actually tracking everything in CoParentSplit, I saw that I'd been covering way more than my share without even realizing it.

Which Medical Expenses Can You Actually Enforce?

Not every health-related cost is enforceable. Courts generally distinguish between necessary and elective medical care. Here's a rough breakdown based on family law precedent across most U.S. and Canadian jurisdictions:

Almost Always Shared

Emergency room visits and urgent care
Prescription medications
Dental cleanings, fillings, extractions
Vision exams and prescription eyewear
Vaccinations and well-child checkups (not covered by insurance)
Physical therapy prescribed by a doctor
Mental health treatment recommended by a professional

Usually Shared (But Can Be Disputed)

Orthodontics (braces, Invisalign)
Allergy treatment and testing
Therapy and counselling beyond initial assessment
Speech therapy or occupational therapy
Dermatology for medical conditions (not cosmetic)

Often Contested

Elective procedures (cosmetic dentistry, non-essential surgeries)
Alternative medicine (chiropractic, naturopathy, acupuncture)
Over-the-counter supplements and vitamins
Experimental treatments

The key phrase in most court orders is "reasonable and necessary." If a licensed doctor or dentist recommended it, you're on solid ground. If it's something you chose without medical advice, your co-parent has a stronger case to refuse.

How to Protect Yourself Going Forward

Prevention beats litigation every time. Here's what I'd recommend based on two years of co-parenting three kids.

Put it in writing from the start. If you're still negotiating your separation agreement, push for specific language about medical expenses. Define what counts, define the split percentage, define the timeline for reimbursement (30 days is standard), and define what happens if one parent doesn't pay.

Keep insurance information accessible to both parents. Both of you should have copies of insurance cards, know the policy number, and understand what's covered. Half the medical expense disputes I see on r/coparenting happen because one parent doesn't check if insurance covers something before paying out of pocket.

Agree on a notification process. For non-emergency expenses over a certain threshold ($50, $100, whatever works for you), agree that the paying parent notifies the other within 48 hours and provides documentation.

Use a shared tracking system. I know, I built one, so I'm biased. But even if you use a spreadsheet or a notebook, the point is the same: when every medical expense is documented with a date, a receipt, and a category, there's nothing to argue about. If you want to see how expense categories work in practice, check out our co-parenting expense categories guide.

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What If Your Co-Parent Claims They Can't Afford It?

This one's tricky. "I can't afford it" and "I won't pay it" are legally different.

If your co-parent genuinely can't afford their share, courts can adjust the split. Most jurisdictions allow modification of support orders when there's a "material change in circumstances" like job loss or serious illness. Your co-parent would need to file for modification though. They can't just decide on their own to stop paying.

If they're choosing not to pay? That's contempt, and the court can enforce it through wage garnishment, liens, or other remedies.

A few practical realities:

Going to court costs money and time. For a $140 glasses bill, it's probably not worth it on its own.
But if you're documenting every unpaid expense and the total reaches $500, $1,000, $2,000 over several months, that's a different conversation.
Some family lawyers offer a "demand letter" service for $150-$300. Sometimes a letter on legal letterhead gets results faster than months of WhatsApp messages.

My advice? Don't let the small amounts slide just because each one feels too small to fight over. Log them. Track them. Know what to do when your co-parent won't split expenses. When the pattern becomes clear and the total becomes significant, you'll have everything you need.

Do You Need a Lawyer for Medical Expense Disputes?

For most co-parents, no. Not right away.

If your court order clearly states the split and your co-parent is ignoring it, you can file a contempt motion yourself in most jurisdictions. Court clerks can often point you to the right forms. The filing fee is typically $50-$200.

You might want a lawyer if:

Your order is vague about medical expenses and needs modification
The unpaid amount is substantial (over $2,000)
Your co-parent has a history of ignoring court orders
There are related custody or support issues tangled up with the expense dispute

As of April 2026, many family courts in the U.S. and Canada also offer mediation services specifically for financial disputes between co-parents. Mediation typically costs $100-$300 per session (split between both parents) and resolves faster than going before a judge.

Keep Records Like a Court Is Watching (Because It Might Be)

The single best thing you can do for yourself is document everything, starting today. Every medical expense. Every text message. Every receipt. Every time you asked for reimbursement and every response (or non-response) you got.

Family court judges see hundreds of cases. The parent who walks in with organized records, clear timelines, and documented communication wins. Not because they're petty, but because they're prepared.

Whether you use CoParentSplit, a spreadsheet, or a shoebox full of receipts (please don't), the habit of logging expenses the same day they happen is what separates the parents who get reimbursed from the ones who don't. I learned this the hard way. I used to forget to log things for weeks, and by then I couldn't remember if I'd spent $45 or $65 at the pharmacy. Now I log it before I leave the parking lot.

Stop fighting about money. Start tracking it. Try CoParentSplit free and see every shared medical expense in one place, with automatic notifications to your co-parent and a clear record of who owes what.