The BabyHydrate Guide

1 · Getting started

There is no signup, no account, and no tutorial. The first launch shows exactly one sheet, then you are on the Watch screen and ready to log.

2 · What OK, Watch, and Call mean

The hero card on the Watch screen shows one of three statuses. Each is derived — computed from the timestamps you logged, compared against cited, age-banded pediatric thresholds, and re-computed continuously against the clock. You can't set it, and neither can the app's marketing department. It is observational, never a diagnosis: the app reports how your logged counts compare to published numbers, nothing more.

The two numbers that drive it

• Time since last wet — a large, ticking counter. The single earliest home signal pediatricians ask about.
• Wet · 24h rolling — how many wet diapers in the last 24 hours, counted backwards from right now (see section 6 for how this differs from the per-day trend).

The rules it follows

These are the draft thresholds the engine compares against, by age band. They are shown in-app with their sources and review date, and the engine always picks the more conservative number where sources differ:

Sources (cited and dated in the app): AAP / HealthyChildren.org (Signs of Dehydration in Infants & Children), Nationwide Children’s Hospital (Diarrhea / Dehydration), Cleveland Clinic (Baby Diarrhea: When to Worry), CHKD (Diarrhea, Vomiting, and Dehydration in Newborns), Canadian Paediatric Society (Dehydration and diarrhea) — reviewed June 2026. Pediatric guidance notes a baby can become dangerously dehydrated within 24–48 hours — when in doubt, call.

3 · Logging

Every event type is one or two taps from the main screen. Each log gets a haptic confirm so you can do it without looking.

💧 Wet diaper — one tap

The biggest, most central button in the app (and the big center button in the tab bar). One tap logs a wet diaper at the current time. This is the event the whole app exists for.

💩 Stool — two taps

Tap Stool, then pick normal, loose, or watery. The distinction matters: watery stools drive the illness-watch view, and for babies under 3 months any loose or watery stool immediately raises the status to Call (young infants dehydrate fastest — that rule comes from the cited sources, not from us).

🤢 Vomit — one tap

Logged at the current time. Repeated vomiting alongside low diaper output is exactly the pattern the When-to-call card describes.

🍼 Fluid — two taps, amount optional

Pick what was offered — breast, formula, oral rehydration solution, water, other — and optionally enter the amount. The amount is never required, and the app never suggests how much to give. It records what you tell it, full stop. Feeding amounts and rehydration are between you and your pediatrician.

🌡️ Temperature — two taps

Enter the reading in °C or °F (switchable in settings). Temperatures are kept for your records and included in the pediatrician hand-off; the app does not interpret them.

4 · Editing timestamps and undo

The vigil is messy. You change a diaper at 4 a.m. and remember to log it at 5. That's normal, and the app is built for it:

• Edit the timestamp of any event from the last 24 hours — “it was actually an hour ago.” The status, the rolling count, and any scheduled alert all re-derive instantly from the corrected time. Honest timestamps mean honest counts.
• Undo last is one tap on the Watch screen — a mis-tap never pollutes the log. Undo restores the exact prior status.
• Swipe to delete any event from the list. Nothing is destructive without a deliberate gesture, and deletions are recorded in the log's audit trail.

5 · Starting and ending an illness watch (episodes)

An episode is the app's word for one illness — the bounded stretch of days you are actually watching. Episodes are what make the trend and the doctor hand-off possible.

Past episodes remain viewable and exportable free, forever. Your illness history is medically meaningful and is never held hostage — by a paywall or anything else.

6 · The per-day trend vs the rolling 24h count — why they differ

The app shows two different wet-diaper numbers, on purpose, and labels them everywhere:

• “Wet · 24h rolling” (on the hero card) counts backwards 24 hours from right now. It answers “how is she doing today?” and it moves with the clock — at 3 p.m. it covers yesterday 3 p.m. to now.
• “Wet diapers per day” (in the trend chart and exports) counts by calendar day. It answers the more dangerous question: “is she doing worse than yesterday?”

They will often disagree slightly, and that's correct — they measure different windows. The rolling number is the early-warning input for the status engine; the per-day bars expose a decline across days, which a single 24-hour figure structurally hides. Eight wet diapers on day one and four on day nine can both be “a number” — the downward staircase between them is the thing pediatricians want to know about, and it's what the trend chart (and the prolonged-illness flag) exists to surface.

7 · The dehydration sign check

Diaper counts are one signal; your baby is the rest. The sign check is a deliberate, guided checklist of the urgent signs listed by the cited pediatric sources — you observe, the app records. If you mark any urgent sign as present, the status goes straight to “Call your doctor,” no matter how many wet diapers were logged.

The urgent signs (any one → Call)

Quoted from the app's source-reviewed checklist:

Source-reviewed list — AAP / HealthyChildren.org, Nationwide Children’s, Cleveland Clinic, CHKD, Canadian Paediatric Society; reviewed June 2026. The sources are blunt: babies can become dangerously dehydrated within 24–48 hours — when in doubt, call.

Reassuring observations

The check also lets you record reassuring observations — for example:

These go into the record and the pediatrician hand-off — doctors want to hear what looked fine, too — but they never lower the status. Only logged wet diapers can do that. An urgent sign keeps the status at Call until a newer, deliberate re-check omits it; after about 12 hours the app prompts you to re-check rather than letting an old assessment go quietly stale.

8 · The When-to-call card, your pediatrician, and the emergency button

The When to call card is reachable from every screen in the app — including the paywall and Nursery Mode — and is always free. It shows the warning thresholds for your baby's age band, in plain words, driven by the exact same data the status engine uses, so the card and the status can never disagree.

• Under 3 months gets its own loud rule: call the pediatrician for any diarrhea. Young infants dehydrate fastest — don't wait to count diapers.
• Save your pediatrician's number once, and “Call pediatrician” is one tap from then on.
• The emergency button dials your region's emergency number. It is never gated, never delayed, never behind anything.
• The card carries a neutral fluids line — “your pediatrician may recommend an oral rehydration solution” — and deliberately stops there. No amounts, no dosing, ever.

Sourced & dated in-app: the card's thresholds cite AAP / HealthyChildren.org, Nationwide Children’s, Cleveland Clinic, CHKD, and the Canadian Paediatric Society — reviewed June 2026.

9 · Nursery Mode

One tap on the moon icon turns the Watch screen into a 3 a.m. instrument: near-black background, a dimmed amber palette emitting as little light as possible, an oversized “time since last wet,” and a huge Wet button in the bottom half of the screen where your thumb already is.

• The app suggests it automatically at night (roughly 10 p.m.–6 a.m.), but you decide.
• It stays on until you toggle it off — independent of the system dark mode.
• Everything still works: sign check, When-to-call, undo. Status is still shown with icon + text + color, never color alone.
• Free, forever. Being usable in the dark is safety, not a premium theme.

10 · Notifications — what they do and honestly don't

The threshold-crossing alert (free)

Whenever you log or the status recomputes, the app schedules one local notification at the exact time the next threshold would be crossed — for example: “No wet diaper logged in 6h — check on baby and log.” If you log a wet diaper before then, the alert quietly reschedules itself further out. This works with the app closed, because the notification is scheduled in advance on your device.

The app asks for notification permission when you start your first illness watch — the moment it actually matters (“Want an alert if a threshold is crossed overnight?”) — never at first launch.

What “time-sensitive” honestly means

The alert is marked time-sensitive, which lets it break through some quiet modes on iOS. Honest caveat: a Focus mode configured to exclude time-sensitive notifications can still silence it, and so can turning notifications off for the app. No app can truthfully promise its alert “always gets through” — so if you are relying on an overnight alert, check your Focus settings before the night shift. The alert is a reminder, not a guarantee, and never a substitute for checking on your baby.

Re-check cadence reminders (Pro)

With Pro, you can add reminders on your schedule while a watch is open — “remind me every 2 / 3 / 4 hours” — phrased as what they are: “Time to check — log what you find.” They are parent-configured prompts to check and log, never instructions about care. They respect quiet hours and stop automatically when the watch ends.

All notifications are local — scheduled and delivered on your device. There is no push server (see the privacy policy).

11 · Exports — the pediatrician hand-off

“How many wet diapers a day, since when, how many watery stools?” is the first thing a pediatrician asks. The export answers it in their preferred shape:

• Plain text (free): a compact episode summary — wet count per calendar day, the latest rolling-24h figure, stools by type, vomits, fluids offered, temperatures, and any urgent signs with timestamps. Each line labelled with its metric (per-day vs rolling, always disambiguated).
• CSV (free): the same data as a spreadsheet for anyone who wants to chart it.
• JSON backup (free): your complete raw log, for your own keeping. Local-only apps owe you a copy of your own data.
• Formatted PDF report (Pro): the same hand-off as a clean, printable document — with the same “generated on-device, not medical advice” footer as everything else.

Exports are generated on your device and go only where you send them via the iOS share sheet. Nothing is uploaded anywhere by the app.

12 · Pro features

BabyHydrate Pro is a one-time $12.99 purchase (no subscription), shared with your family via Family Sharing. The rule it lives by: safety is always free — Pro only buys convenience.

• Overnight Watch: a Lock-Screen Live Activity counting “time since last wet” all night, plus interactive Home- and Lock-Screen widgets with a one-tap Wet log. Honest platform note: iOS limits how long a Live Activity stays live (roughly 8–12 hours); the app refreshes it when you open or log, and the free threshold alert — not the Live Activity — remains the safety mechanism.
• Re-check cadence reminders on your own schedule (see section 10).
• Formatted PDF pediatrician report (text and CSV stay free).
• Multiple children (the free app tracks one).
• Cross-episode insights: compare this illness with past ones. Viewing and exporting past episodes is free; the comparison view is Pro.
• Alternate icons and accent themes.

Purchases and refunds are handled entirely by Apple. Restore Purchases works on any device on your Apple ID, and if Pro is ever revoked the app downgrades without deleting anything.