Published: April 10, 2025 Updated: October 20, 2026
More than 20 states have passed consumer protections that allow Medigap plan holders to switch between Medigap plans without underwriting. New Mexico is one of the newest to pass birthday rule legislation, which will begin during Open Enrollment on January 1, 2027. New Mexico Medigap beneficiaries will soon be able to change plans with guaranteed issue during a 60-day window that starts on the first day of their birthday month. Participants can move to a new plan with any carrier so long as the new plan has benefits that are equal to, or less than, their current one.
If you recently had employer-sponsored health benefits or a Medicare Advantage plan, you’re probably used to annual enrollment – the time of year when you can change your plan to make sure it fits your health needs and budget.
But if you’re enrolled in a Medigap plan, federal laws allow you to make changes to your plan at any time, as long as you go through medical underwriting. According to federal rules you can apply for a plan during your Initial Enrollment Period without underwriting, which is three months before your 65th birthday, your birthday month, and the three months after. This is the window where you enroll in Original Medicare and have guaranteed acceptance for a Medigap plan.
But several states have passed legislation that keeps Medigap participants from being locked into their plan. The Medigap Birthday Rule is guaranteed issue protection provided by your state. These rules let you switch to a new plan, usually of equal or lesser benefits, without going through medical underwriting. Even if your state doesn’t have a birthday rule, you aren’t trapped in your plan forever. Read on to find out what to do if you’re considering switching your coverage.
Birthday Rule and Anniversary Rule differences
Some state legislatures have passed laws allowing people to switch Medigap plans with guaranteed issue rights. This means you can move from one plan to another without going through underwriting. During underwriting, your insurance carrier will ask questions about your health. They use this information to decide whether you can purchase a new plan and if your costs will be higher because of any health issues.
But Birthday Rules and Anniversary Rules help you avoid that process and let you switch Medigap plans at the same price as anyone else applying.
- Birthday Rules tend to be 30-63 days around your birthdate or birthday month.
- Anniversary Rules are periods of time surrounding the anniversary date of enrollment in your Medigap policy.
A handful of states have passed legislation that allows you to switch plans any time of the year without underwriting. Most of these other Birthday Rules allow you to move from your current plan to one that has equal or lesser coverage. To change to a more robust plan, you’ll usually have to go through underwriting.
State-by-state breakdown and 2027 updates
More than 20 states have passed consumer protections that allow Medigap plan holders to switch between Medigap plans without underwriting. New Mexico is one of the newest to pass birthday rule legislation, which will begin during Open Enrollment on January 1, 2027. New Mexico Medigap beneficiaries will soon be able to change plans with guaranteed issue during a 60-day window that starts on the first day of their birthday month. Participants can move to a new plan with any carrier so long as the new plan has benefits that are equal to, or less than, their current one.
Here’s a guide for Medicare Supplement birthday rules by state.
| State Category | Participating States (2027) | Key Rules & Window Length |
|---|---|---|
| New for 2027 | New Mexico | 60-day window starting birth month; equal or lesser benefits; any carrier. |
| Recent Enactments (2025–2026) | Indiana, Delaware, Virginia, West Virginia, Wyoming | 30- to 63-day windows around birthday; equal/lesser benefits. Note: WV has a 24-month prior coverage requirement. |
| Established Birthday States | CA, OR, ID, IL, NV, LA, MD, KY, OK, UT | Windows range from 30 to 63 days around birth month. |
| Anniversary Rule States | Missouri | 30-day window surrounding policy anniversary date. |
| Continuous Enrollment | NY, CT, VT, MA | Year-round guaranteed-issue switching protections. |
Note: Some states require you to keep the same carrier when you switch, and others allow you to change carriers. Some have an age bracket – for instance, you must be 65 to 75 to switch in Illinois. Some, like Virginia, require you to switch to a plan that is at least as good as the plan you currently have.
What if my state doesn’t have a Birthday Rule?
If states haven’t passed legislation regarding Birthday Rules or Anniversary Rules, they must follow federal law. If you live in one of these states, you’ll have to go through underwriting to change plans outside of your Medigap Open Enrollment period.
During underwriting, there are some standard questions you should be prepared to answer. These include:
- Your age and gender,
- Any alcohol, drug, or tobacco use or misuse,
- If you have chronic health conditions,
- If you have had, or need to have, major medical care like a hospitalization or surgery,
- What prescription medications you take,
- Your family health history,
- Your physical and mental health history,
- Your weight or body mass index.
Answering these health questions can be a scary proposition. But many people get through underwriting without any issues. Even people with some chronic health conditions may get through the process or have a waiting period to qualify.
Note: Many of these states that allow you to change plans only permit moving to an equal or lesser plan. This means if you want to change to more comprehensive coverage, it may not be an option for you even in a Birthday Rule state.
Understanding equal or lesser benefits
In most states, you can’t change the plan letter during anniversary or birthday changes to one with more robust coverage, such as changing from a Plan N to a Plan G (Plan G covers Part B excess charges while Plan N does not). You’ll often have to choose one with the same or fewer covered benefits. Carriers base equal or lesser coverage on the Medigap plan letter.
There are 10 plan letters in most states: A, B, C, D, F, G, K, L, M, and N. These letters designate the benefit coverage each plan provides as well as the cost (plans that cover less are usually also less expensive). For instance, Plan N has robust coverage, and Plan A has less, so you couldn’t switch from the former to the latter.
Some states also make you stick with the same carrier you already have. This makes it harder to shop around and reduces the chances you’ll be able to find an equal or lesser plan than the one you already have that still fits your healthcare needs.
Birthday Rule checklist
If you are a Medigap plan holder and are considering switching plans, here are some things to remember to make sure you don’t miss your enrollment window.
- Check to see if your state has birthday or anniversary rules.
- Mark your calendar so you’ll remember to start reviewing plans 60 days before your birth month (or anniversary date).
- Compare premiums of plans you think may fit your needs – a licensed insurance agent like those at SmartMatch can help you find a plan for your budget.
- Enroll in the new plan during your enrollment window.
- Don’t cancel your existing coverage until you’ve officially been approved for your new plan (this is important to avoid potential coverage lapses).
Don’t be afraid to look around for a Medigap plan if you are already insured. State Birthday Rules may help you get a new plan that provides good coverage and lowers your monthly premiums. Even in states that don’t have these rules, underwriting is available and not as scary as it seems. If you’d like to browse Medicare Supplement rates, see Medigap rates by state here.
