Newborn Week 4: What to Expect
Your baby's development, feeding, sleep, your postpartum body, mental health, and what to watch for this week.
What your baby looks like at week 4
Most babies are 1–2 lbs above birth weight. Head circumference has grown ~1 inch. Skin is clear, often soft. Baby is rounder. The "alien newborn" look is gone; they look like a baby in baby photos.
Baby's development this week
Brief social smile may appear by end of week 4 (true smile, not gas). Tracks faces and slow objects across midline. Holds head up briefly during tummy time (5–10 seconds). Vision improving — sees about 12 inches clearly, prefers high-contrast and faces. Coos appearing — vowel sounds, "ahh," "oooh." Recognizes familiar voices and turns toward them.
Feeding at week 4
7–10 feeds per 24 hours typical now. Breastfed babies often take 20–30 minutes per feed. Formula babies typically take 3–4 oz per feed, 6–8 times per day. Growth spurt around week 4 — expect extra cluster feeding for 1–3 days. Watch for hunger cues, but most babies have a more predictable feed-sleep rhythm starting to emerge.
Sleep this week
14–16 hours per 24. Wake windows 75–90 minutes. Many babies have one 4–6 hour stretch at night now (not always at the parent-convenient time). Day/night confusion mostly resolving. Naps are still 30–60 min usually, sometimes longer. Continue swaddling — most babies still benefit. Always back to sleep.
How your body is doing
Lochia should be light or fading. If it returns to bright red or heavy, slow down — you're overdoing it. Hair shedding may be noticeable now. Hormones are still adjusting. Pelvic floor is healing but not healed; rebuilding strength is a marathon (don't run yet). Mental load is heavy — partner conversations about division of labor are crucial right now.
Your mental health this week
Baby blues should be fully resolved by now (week 2). If you're still daily-tearful, anxious, intrusive-thought-having, or feeling disconnected: that's PPD or PPA. Get evaluated. 1 in 7 moms develops PPD; 10–20% experience PPA. Both are treatable. SSRIs (some are breastfeeding-compatible) and therapy work. Don't suffer because of stigma or because you think you should be "strong enough."
When to call the pediatrician
Fever ≥100.4°F still warrants ER for under-3-months. Inconsolable crying, refusal to feed, breathing concerns, lethargy, projectile vomiting, blood in stool.
Survival tips for week 4
Start mini-routines: a feed-play-sleep loose rhythm (also called EASY). Don't rigidly schedule yet. Tummy time 3x daily for 3–5 min each. Talk to your baby constantly — narrate everything. Their language brain is wiring up. Take a real shower. Go for a walk. Eat lunch sitting down.
For your partner
If mom is breastfeeding, this is when a partner-given bottle of pumped milk becomes useful for date nights or solo sleep stretches. Take an evening shift weekly. Praise often and specifically — "thank you for doing X" matters more than "you're a great mom."
Pediatric visits this week
1-month well-check is usually at week 4 — weight, length, head circumference plotted on growth chart, developmental check, first round of supplements (vitamin D for breastfed babies), and any vaccines (Hep B might be #2 if not done yet).
Gear focus
Same as last weeks. Consider: bottles + pump if returning to work soon, an activity mat for floor play, a noise machine for the parent room (if baby's noises wake you).
Is this normal?
If your baby smiled at the dog before they smiled at you, doesn't seem to "love" anyone specifically yet, or is more attached to the swing than to your face — that's completely normal at week 4. Attachment forms over months, not days.
Track your baby's wake windows
Newborn wake windows are short and shift weekly. The free Wake Windows Calculator gives you the right window for any age and helps prevent overtired meltdowns.
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