TL;DR
- Company: Happiest Baby, Inc., maker of the SNOO Smart Sleeper
- Date: FDA Warning Letter, MARCS-CMS #718306, issued June 15, 2026
- Classification: Medical device — adulteration and misbranding
- Key citations: 21 U.S.C. §§ 351(f)(1)(B), 360e(a), 360j(g), 352(o), 360(k); 21 CFR 807.81(a)(3)
- Consequence: 15-business-day window to detail corrective actions to FDA/CDRH
| Company | Location | Letter # | Issued | Issuing Office | Inspection Dates | Classification |
|---|---|---|---|---|---|---|
| Happiest Baby, Inc. | Los Angeles, CA | MARCS-CMS 718306 | June 15, 2026 | FDA/CDRH | July 21–25, 2025 | Medical Device (Adulteration & Misbranding) |
Picture a parent buying a SNOO Smart Sleeper specifically because it's FDA-authorized to help reduce the risk of SIDS. They read the marketing, they trust the claim, and they zip their newborn into whatever sleep sack ships with the bassinet. What they almost certainly don't check is whether that exact sack size is the one FDA actually reviewed. It's a reasonable thing not to check. It's also, according to FDA, exactly where this device stopped matching its authorization.
FDA's Center for Devices and Radiological Health laid out that gap in FDA Warning Letter, MARCS-CMS #718306, June 15, 2026, addressed to Dr. Harvey Karp, Chief Executive Officer of Happiest Baby, Inc., at the company's Los Angeles headquarters. The letter followed an inspection at the firm's LA location from July 21–25, 2025, and a review of the company's website that FDA says it last checked on May 7, 2026.
The SNOO Smart Sleeper isn't a novelty crib. FDA classifies it as a "device" under Section 201(h) of the FD&C Act because it's intended to affect a structure or function of the body: specifically, keeping infants in a supine sleep position, which is associated with lower SIDS/SUID risk. The product reached the market through FDA's De Novo pathway under DEN210039, with an authorized indication covering infants from birth to 6 months who can't yet roll over consistently. That authorization came with a specific mechanism: a bassinet paired with a SNOO Sleep Sack, described in the authorization as a cotton swaddle with fixed wings that extend to the right and left of the infant's body, available in three sizes: Small (5–12 lbs), Medium (12–18 lbs), and Large (18–25 lbs). Nothing smaller, nothing larger.
Violation 1: Adulteration under 21 U.S.C. § 351(f)(1)(B)
FDA's first citation is straightforward in structure, if not in consequence. The agency found that the SNOO Smart Sleeper and the SNOO Hospital Bundle are adulterated under Section 501(f)(1)(B) of the FD&C Act because the firm lacks an approved Premarket Approval application in effect under Section 515(a), and lacks an approved Investigational Device Exemption under Section 520(g), covering the devices as they're currently marketed. The phrase "as currently marketed" is doing real work here. It isn't that Happiest Baby never had authorization. It's that what it's now selling extends beyond what that authorization covers.
That gap traces directly to sizing. FDA's inspection and its review of happiestbaby.com found the firm distributing an unauthorized X-Small Sleep Sack, sized for infants weighing 4–8 lbs, smaller than any size in the original DEN210039 authorization. FDA's letter also states the firm introduced a second new sleep sack size beyond the three originally authorized; the excerpt available here doesn't specify that size's name or weight range, so no detail beyond "a second new sleep sack size" should be assumed. Two new sizes, neither cleared.
Violation 2: Misbranding under 21 U.S.C. § 352(o)
The second citation addresses process rather than the product itself. FDA found the devices misbranded under Section 502(o) because Happiest Baby introduced the modified devices into interstate commerce for commercial distribution without submitting the notice FDA requires for a significant device change or modification, as spelled out in Section 510(k) of the Act and 21 CFR 807.81(a)(3). That regulation is the trigger mechanism: it defines when altering an already-authorized device requires a new premarket notification before the modified version goes out the door.
In plain terms, FDA isn't just saying the new sizes weren't reviewed. It's saying the company was required to tell FDA about the change before selling it, and didn't. Those are two separate failures stacked on the same underlying fact pattern.
Why "just adding a size" isn't a technicality
Here's the part that cuts against how most people picture an FDA warning letter. The mental image is usually a shady overseas generic-drug plant with falsified lab records, not a VC-backed, name-recognized U.S. baby-gear brand with a De Novo-authorized device already on store shelves. Happiest Baby had cleared the hard part. It had FDA authorization, a validated mechanism, three sized sacks that matched a defined weight range tied to how the device is supposed to work.
Adding a fourth and fifth size sounds like a customer-service improvement, not a regulatory event. But for a device whose entire safety claim rests on a fitted swaddle holding an infant in a specific position at a specific weight, size range isn't packaging trivia. It's the mechanism. Expand the range without new data and new FDA sign-off, and you've changed the thing FDA actually reviewed, even if the bassinet itself looks identical on the shelf. That's the core of why this letter exists: not a shortcut on manufacturing, but scope creep on the exact variable the original authorization was built around.
What this means for other device makers
The lesson generalizes past infant sleep products. Any firm holding a 510(k) clearance, De Novo authorization, or PMA approval that later tweaks dimensions, materials, sizing tiers, or intended-use language is running the same risk: a "significant change or modification" under 21 CFR 807.81(a)(3) can turn a cleared product into an adulterated and misbranded one overnight, regardless of intent. As with FDA's broader device quality shift (QMSR medical device rule), the agency has been tightening how closely marketed devices need to track their authorized specifications. The common thread: FDA doesn't grade scope creep on a curve just because the original authorization was legitimate and the company is well capitalized.
Happiest Baby submitted responses to FDA on August 15, 2025, and February 26, 2026, both from Dr. Karp. FDA issued the warning letter anyway, which means the agency reviewed those responses and still found grounds to escalate. No recall, import alert, or injunction is documented against the company in this letter. Unresolved device warning letters can, as a general enforcement-ladder matter, lead to further FDA action such as seizure or injunction, but nothing beyond the warning letter itself is confirmed here.
FAQ
What triggered the FDA warning letter to Happiest Baby?
An FDA inspection at the company's Los Angeles facility from July 21–25, 2025, combined with a review of happiestbaby.com (last checked by FDA May 7, 2026), found the firm distributing sleep sack sizes for the SNOO Smart Sleeper that fall outside the weight ranges authorized under DEN210039.
What are the two violations FDA cited?
Adulteration under 21 U.S.C. § 351(f)(1)(B), for marketing the device without a PMA or IDE covering its current configuration, and misbranding under 21 U.S.C. § 352(o), for failing to submit a required notice under Section 510(k) and 21 CFR 807.81(a)(3) before distributing the modified device.
Was the SNOO Smart Sleeper ever FDA-authorized?
Yes. The device received marketing authorization through FDA's De Novo pathway under DEN210039, for an indication covering supine sleep positioning in infants birth to 6 months, using a bassinet paired with a Small, Medium, or Large SNOO Sleep Sack.
What does Happiest Baby need to do now?
FDA warning letters carry a standard 15-business-day window for the recipient to detail corrective actions. The facts available don't specify what Happiest Baby has committed to beyond its two prior responses (August 15, 2025 and February 26, 2026), which FDA reviewed before issuing this letter.
Source: FDA Warning Letter, MARCS-CMS #718306, June 15, 2026. Byline: The Argus Regulatory Analysis Team. Published 2026-07-14.