The First Twelve Weeks
The "fourth trimester": your baby is adjusting to the outside world, and you're adjusting to your baby. Here's what normal looks like.
- Feeds: 8–12 a day. Diapers by day 5–7: 6+ wet, 3–4 stools.
- Weight dips up to 10%, then back to birth weight by about 2 weeks.
- Crying peaks near 6 weeks at about 3 hours a day, then comes back down.
- Checkups: within 48 hours of discharge, then 1, 2, 4, 6, 9, and 12 months.
The fourth trimester
This one idea reframes almost everything below. Newborns feed constantly, sleep in fragments, and cry in the evening not because something is wrong, but because that's what three-months-early looks like. The numbers that follow tell you what's typical, and the Warning Signs guide covers the short list that isn't.
Feeding & diapers: the daily math
Breastfed: 8–12 feeds per 24 hours, roughly every 2 hours at first, sometimes bunched into evening "cluster feeding" marathons that are normal and say nothing about your supply. AAP CDC
Formula-fed: every 2–3 hours, at least 8 feeds a day: about 0.5–2 oz per feed the first days, then 3–4 oz every 3–4 hours by one month. AAP
The output side is your best gauge that input is working. By day 5–7, expect 6+ wet diapers a day with pale urine and at least 3–4 yellow, seedy stools: AAP
| Day | Stools | What they look like |
|---|---|---|
| 1–2 | 1–2/day | Black, tarry (meconium: alarming-looking, totally normal) |
| 3–4 | 2+/day | Transitioning greenish → yellow |
| 5–7 on | 3–4+/day | Yellow, loose, seedy · plus 6+ wet diapers |
Much more on bottles, formula, and breastfeeding, including safe prep and storage, in the Feeding guide.
Weight: down, then up
Every newborn loses weight at first; up to 8–10% of birth weight is within normal. Steady gain starts around day 5, most babies are back to birth weight by 2 weeks (almost all by 3), and then gain roughly an ounce a day for the first month. Your pediatrician tracks this at the early visits, which is exactly why those visits are packed so close together. AAP AAP
Crying: the curve every parent should see
Crying rises from birth, peaks around 6 weeks at about 3 hours a day, and falls to 1–2 hours a day by 3–4 months. Evening fussiness (the "witching hour," often 6 p.m.–midnight) is the standard pattern. About 1 in 5 babies gets colic (intense, inconsolable crying starting weeks 2–4), and it, too, generally resolves by 3–4 months. AAP
Knowing the curve exists changes how the 6-week trenches feel: it isn't getting worse forever; you're near the top of the hill.
Reading your baby: the six states
Newborns cycle through six states of consciousness, and learning to spot them is like getting subtitles. AAP
| State | What you see | What to do |
|---|---|---|
| Deep sleep | Still, breathing even | Nothing. Eat something. Shower. |
| Light sleep | Wiggles, flutters, little noises | Wait — babies are noisy sleepers; don't rush in |
| Drowsy | Glazed, heavy lids | Great moment to put baby down for sleep |
| Quiet alert | Eyes wide, face bright, body calm | The golden window: talk, sing, read, play |
| Active alert | Squirmy, fussing building | Feed, change, or wind down before it tips over |
| Crying | You'll know | Soothe; see the 5 S's |
Quiet alert is when babies are most responsive and involved; a few minutes of face-to-face time here does the most good. It's brief in newborns and grows with age. AAP
The body stuff: cord, jaundice, checkups
Umbilical cord
Keep the stump clean and dry, fold the diaper below it, and let it fall off on its own, by about 3 weeks. A few drops of blood are normal; foul-smelling discharge, red skin at the base, or pain when touched mean call the pediatrician. AAP
Jaundice
Very common: a newborn liver needs a few days to get going, so many babies go a bit yellow in the first days. Every baby should have a bilirubin check before hospital discharge; babies discharged before 48 hours should be rechecked within 2 days. Call the doctor if the yellow deepens or spreads to the belly, arms, or legs, the eye-whites yellow, or the baby is hard to wake or feeding poorly. Treatment, if needed, is usually just light therapy. AAP
Screenings before you leave the hospital
Three quick ones, all standard: the heel-stick blood test (screens for dozens of inherited conditions; the exact panel varies by state), a hearing screen, and a pulse-ox check for heart defects. If the hearing screen isn't passed, it's usually fluid, but follow up: full testing by 3 months is the national benchmark. MedlinePlus CDC
The checkup schedule, year one
First visit within 48 hours of discharge (often day 3–5), then around 1, 2, 4, 6, 9, and 12 months. These visits track weight, feeding, development, and give you a standing appointment to ask everything you've been googling. AAP
Vaccines in year one
Shots cluster at the well visits: a hepatitis B dose at birth, then rounds at 2, 4, and 6 months (DTaP, polio, Hib, pneumococcal, rotavirus, more HepB), flu vaccine yearly from 6 months, and MMR + varicella at 12 months. RSV protection is given at birth, season-dependent, if you didn't get the maternal vaccine. CDC
About the headlines: in 2025–2026 the federal vaccine schedule became the subject of an active policy and court fight, with changes voted, adopted, and then stayed by a federal injunction. The American Academy of Pediatrics publishes its own schedule and has kept all routine recommendations, including the birth-dose, unchanged, and as of mid-2026 the CDC's posted schedule matches it. Practical upshot: follow the AAP schedule, and let your pediatrician be your guide if headlines change again. Georgetown CCF CDC