Healthcare costs continue to climb for tens of millions of Medicare beneficiaries, with the average senior spending over $7,000 annually on medical expenses, even with Medicare coverage. Given those high out-of-pocket costs, roughly one in four Original Medicare enrollees opt to turn to Medicare supplemental insurance, also known as Medigap, to help bridge the coverage gaps. The problem is, though, that many seniors later find themselves locked into their initial Medigap plan.
In these cases, these adults find themselves unable to switch to potentially better or more affordable supplemental options due to the medical underwriting requirements that exclude those with pre-existing conditions. What many Medicare beneficiaries don’t realize, though, is that some states have implemented special rules that can provide an annual escape hatch from this predicament.
These lesser-known provisions, often called “birthday rules,” can open doors that otherwise remain firmly shut for adults seeking to optimize their supplemental coverage. And, understanding these rules could mean the difference between paying a lot more each year for the same level of protection and not.
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What is the Medigap birthday rule?
The Medigap birthday rule isn’t actually a single, uniform federal regulation. Rather, it refers to state-specific laws that give Medicare beneficiaries special enrollment periods tied to their birthdays, allowing them to switch between certain Medigap plans without the usual medical underwriting hurdles.
When you first sign up for Medigap at age 65, you typically get a six-month open enrollment period where insurers can’t deny you coverage or raise your rates because of health issues. But after that period ends, switching policies usually requires you to go through underwriting. That means insurers can charge you more or even turn you down if you’ve developed new health conditions.
As of 2025, about 18 states have implemented some version of a birthday rule. California leads the pack with perhaps the most generous version, allowing beneficiaries to switch to any Medigap plan with equal or lesser benefits during a 60-day window surrounding their birthday each year. The key advantage of this is that insurance companies cannot ask health questions, impose waiting periods for pre-existing conditions or deny coverage based on medical history during this window.
Other states have different versions of this rule. For example:
Oregon allows a 30-day window around your birthday when you can switch to a plan with equal or lesser benefits without underwriting. You can also switch insurers during that period.
Idaho provides a 63-day window after your birthday for switching to a plan with the same level or a lower level of benefits.
Illinois offers a birthday rule for seniors ages 65 to 75, giving them 45 days to switch to a plan of equal or lesser value.
Nevada and Louisiana recently added their own birthday rules, with similar protections.
The birthday rule differs significantly from other special enrollment periods, such as the federal guaranteed issue rights that apply in specific situations like losing employer coverage. While those federal protections are important, they’re triggered by particular life events and may not help someone who simply wants to find a better deal or switch to a plan that better meets their evolving needs. Each state’s rule comes with its own specific requirements, timeframes and limitations, though, making it crucial for beneficiaries to understand their particular state’s provisions.
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How does the Medigap birthday rule impact seniors?
For seniors living in states with birthday rules, the impact can be substantial and multifaceted. The most immediate benefit is financial flexibility. Medigap premiums can vary dramatically between insurance companies for identical coverage, sometimes differing by hundreds of dollars per month. Without a birthday rule, a senior who develops health issues after their initial Medigap open enrollment period might find themselves permanently stuck with a high-premium plan.
The rule also provides peace of mind and planning flexibility. Seniors can make coverage decisions based on their current financial situation and preferences rather than feeling trapped by past choices. This is particularly valuable as needs change with age. Someone who prioritized the lowest premium at age 65 might later prefer a plan from a company with better customer service or different provider networks, especially if their health status would otherwise make switching impossible.
However, the birthday rule isn’t without limitations. In most states, you can typically only move to plans with equal or lesser benefits. This means if you start with a basic Plan A, you might be able to switch to another Plan A but not upgrade to the more comprehensive Plan G. And, while you’re protected from medical underwriting, you’re not necessarily guaranteed the lowest available rate. You’ll typically pay the standard rate for your age and gender that the new company charges.
The bottom line
The Medigap birthday rule represents a valuable but often underutilized tool for Medicare beneficiaries in the handful of states that offer it. For eligible seniors, it can unlock significant savings opportunities and provide ongoing flexibility in their supplemental coverage choices. However, the rule’s state-specific nature and varying limitations mean that understanding your local provisions is essential.
If you live in a state with a birthday rule, mark your calendar and review your options annually. Compare premiums, customer service ratings and company financial stability. Even if you’re satisfied with your current plan, taking a look during your birthday rule period costs nothing and could identify substantial savings.