Her Medigap Premium Jumped to $228 a Month. The Birthday Rule Let Her Switch Without a Single Health Question.

*7 min read · Last updated June 30, 2026*

In this article

– Why switching Medigap usually requires passing a health exam – What the birthday rule actually does – The fine print that trips people up – How to use your window before it closes – Frequently asked questions

Renee Carter turned 71 and opened a letter from her Medigap insurer raising her Plan G premium to $228 a month, up from the $145 she paid when she first enrolled at 65. She wanted to shop for a cheaper version of the exact same coverage, but she had a heart condition and assumed no other insurer would take her. For most of the year, she would have been right. Medigap is one of the few insurance products where, once your first enrollment window closes, your health can be used against you. But Renee lived in California, and her agent told her about a rule tied to her birthday that changed everything. Within her window, she moved to another carrier’s Plan G at $171 a month, answered zero health questions, and cut her premium by about $680 a year.

The savings were not a discount or a promotion. They came from a state protection most people on Medicare have never heard of.

Why switching Medigap usually requires passing a health exam

Medigap, also called Medicare Supplement insurance, is private coverage that pays the deductibles and coinsurance Original Medicare leaves you with. How it differs from Medicare Advantage is laid out in Medicare Advantage versus Medicare Supplement.

When you first sign up at 65 and enroll in Part B, you get a one-time, six-month Medigap open enrollment period. During those six months, insurers must sell you any plan they offer at the best rate, regardless of your health. After that window closes, the protection disappears in most states. If you try to switch plans later, the insurer can require medical underwriting, meaning it reviews your health history and can charge you more or refuse you entirely. This is the trap Renee thought she was in, and it is the same underwriting wall described in Medigap medical underwriting after open enrollment.

What the birthday rule actually does

A small group of states created the birthday rule to break that wall once a year. In a birthday-rule state, a set window opens around your birthday during which you can switch to another Medigap plan with the same or fewer benefits, and the new insurer cannot use your health to deny you or raise your rate. It is guaranteed issue, the same protection you had at 65, handed back to you annually.

The states that have adopted a version of this rule include California, Oregon, Idaho, Illinois, Nevada, Louisiana, Maryland, Oklahoma, and Kentucky. The details differ in each one. In plain terms, the rule lets you keep the coverage you have while shopping every other insurer that sells the same plan, so you can chase a lower price for identical benefits. Because all Medigap plans of the same letter are standardized by law, a Plan G from one carrier pays the same as a Plan G from another. The only real difference is the premium, which is exactly what the birthday rule lets you go fix.

The fine print that trips people up

The birthday rule is powerful, but three limits decide whether you can actually use it, and missing any one of them costs you the chance for a full year.

First, the window is short and tied to your birthday, not the calendar year. Depending on the state, it runs roughly 30 to 63 days, sometimes starting on your birthday and sometimes the first of your birthday month. Miss it and you wait another year. Second, you can generally only move to a plan with equal or lesser benefits. If you have Plan G, you can switch to another Plan G or step down to a leaner plan, but you usually cannot jump up to richer coverage without underwriting. Third, the rule only applies if your state has it. Most states do not, and in those states switching still requires passing underwriting unless you qualify for a separate guaranteed-issue situation.

One more point worth knowing: the birthday rule is separate from the Medicare Advantage trial right, which is its own guaranteed-issue path back into Medigap and is explained in the Medicare Advantage trial right window. They solve different problems, and you may qualify for one without the other.

How to use your window before it closes

If you live in a birthday-rule state, treat the weeks before your birthday as a deadline. Pull your current plan letter and premium, then ask a licensed Medigap broker or your state’s free SHIP counseling program to gather quotes for the same plan letter from every carrier in your area. Because the plans are standardized, you are comparing nothing but price and the insurer’s service record.

When your window opens, you submit the switch with no health questions, and the new plan replaces the old one. Renee marked her birthday on the calendar, had three quotes ready, and made the change in a single afternoon. The retirees who overpay year after year are usually the ones who assumed a health condition locked them in for life and never asked whether their state hands them a way out. If yours does, that yearly window is worth more than almost any other move you can make on a fixed income.

Frequently asked questions

What is the Medigap birthday rule? It is a state protection that gives you a short window around your birthday each year to switch to another Medicare Supplement plan with equal or fewer benefits, without medical underwriting. The new insurer cannot deny you or raise your premium based on your health during that window.

Which states have a Medigap birthday rule? States that have adopted a version include California, Oregon, Idaho, Illinois, Nevada, Louisiana, Maryland, Oklahoma, and Kentucky. The window length and exact rules differ in each state, so confirm the current details with your state department of insurance before you rely on them.

Can I switch to a better Medigap plan using the birthday rule? Usually no. The rule lets you switch to a plan with the same or fewer benefits than you currently have. You can move to another carrier’s version of your plan to get a lower price, or step down to leaner coverage, but moving up to a richer plan typically still requires passing medical underwriting.

How long does the birthday rule window last? It depends on the state, but it generally runs about 30 to 63 days. Some states start the window on your birthday and others on the first day of your birthday month. Because it is short, you should have your replacement quotes ready before the window opens.

Will my new Medigap plan cost less for the same coverage? It can. Because Medigap plans of the same letter are standardized by law, a Plan G from one insurer pays the same claims as a Plan G from another. The premium is the main difference, so shopping carriers during your birthday window can lower your cost for identical benefits.