At 71, She Is Leaving Advantage for Original Medicare. If Medigap Says No After Dec. 7, She May Be Stuck Without a Supplement

She is 71 and done with prior authorizations and narrow networks, so she wants out of her Medicare Advantage plan for 2027. Open Enrollment runs Oct. 15 through Dec. 7. During that window she switches to Original Medicare starting Jan. 1, joins a stand-alone Part D drug plan and applies for Medigap Plan G at the same time.

At 71, her one-time Medigap enrollment window is long gone. For someone who had Part B at 65, that federal window lasted six months beginning with the first month she was both 65 or older and enrolled in Part B. Outside it, the insurer can medically underwrite her application.

This affects her Social Security check as much as her health. Her Part B premium of $202.90 a month in 2026 comes out of that check no matter what she picks. Whether she also has Medigap affects how much of what’s left is exposed to medical bills.

Two Medicare Decisions, Two Different Clocks

Leaving Advantage is an enrollment choice Medicare processes on schedule. Buying Medigap is a private insurance application. Unless she has a guaranteed-issue right or state law protection, the insurer can ask health questions, request records, charge more, or deny her.

Start with your state’s rules. A 2024 KFF analysis found that only four states required continuous or annual guaranteed issue for Medigap for people 65 and older.

Her Pharmacy Records Can Answer Before Her Doctor Does

Underwritten applications often include a check of prescription history. That report shows drug names, doses, refill dates, and prescribing patterns. Carrier underwriting guides describe using these reports to evaluate Medigap applicants.

One medication can point an underwriter toward a condition, leading to more questions, more weeks of waiting, and sometimes a denial.

How Dec. 7 Can Pass Before the Insurer Decides

She chooses Original Medicare on Nov. 20 and applies for Plan G the same day. Underwriting runs through December, and the denial comes Dec. 15.

By then, annual Open Enrollment has closed. The Medicare Advantage Open Enrollment Period runs Jan. 1 to March 31, but it won’t help her because only people already in an Advantage plan can use it. Unless she qualifies for a separate Special Enrollment Period, she starts January in Original Medicare with no supplement.

What an Uncapped 20% Does to a Fixed Monthly Check

Original Medicare covers hospital stays and doctor visits but lacks a ceiling. Her Advantage plan had a yearly out-of-pocket maximum. Original Medicare on its own has none.

Without Medigap, she pays the $283 Part B deductible, then generally 20% of the Medicare-approved amount for most Part B services. A hospital stay adds a Part A deductible of $1,736 for each benefit period.

Say her Social Security check is $2,000 a month. The latest 2027 cost-of-living adjustment (COLA) estimate is about 3.5%, which would add roughly $70 if it holds.

Now picture a year of outpatient infusions with $50,000 in Medicare-approved charges. Her 20% share is $10,000, almost five months of her adjusted Social Security income. Plan G would have covered nearly all of it once she met the Part B deductible.

Social Security is income she can’t outlive. Medigap can keep much of Original Medicare’s cost sharing from eating into it during one bad medical year.

Get the Medigap Answer While You Can Still Change Course

Every Medicare election before Dec. 7 can be replaced by a later one, and the last one counts. That flexibility only helps if the insurer answers in time. A few steps keep the order of events in your favor:

1. Apply in October, not December. An early application gives the insurer time to underwrite and gives you time to respond. Ask for a Jan. 1 start date so the policy begins when your Advantage plan ends.
2. Get the decision in writing before Dec. 7. If you’re turned down while the window is open, you can pick an Advantage plan again and avoid starting January without protection.
3. Don’t treat putting in the application as approval. A pending application does not guarantee that the insurer will issue the policy.
4. Check protected rights first. If this is your first year in Advantage, a federal trial right may let you buy Medigap without underwriting. Your state may offer more.

Getting the order wrong here is the hardest mistake to undo. You can leave Advantage in a single enrollment window. Getting Medigap takes a separate approval, and the risky wait is the gap between choosing Original Medicare and hearing back from the insurer. Health history, state of residence and past coverage can all change the answer, so confirm your own rules before your choice locks in.

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