Newborn Baby Guide: The First 4 Weeks, Feeding, Sleep & Checkups

What is normal in the first four weeks?

A newborn may sleep and feed around the clock, startle easily, want near-constant contact, and have no recognizable day-night rhythm. Hands and feet can look bluish when cold while the lips and tongue remain pink. What matters is the whole picture: breathing, color, wakefulness, feeding, and whether your baby is changing from their usual pattern.

Babies born before 37 completed weeks need an individualized plan. Their first weeks cannot be compared directly with those of a full-term newborn, and corrected age will matter for development later. Follow the NICU or discharge plan for feeds, temperature, weight checks, supplements, and appointments.

The US newborn timeline: hospital screening and early visits

Before discharge, most babies have a physical exam plus hearing, pulse-oximetry, and blood-spot screening. The blood sample is usually collected at 24–48 hours, but the exact panel and repeat-sample rules depend on your state. Screening is not the same as diagnosis; an out-of-range result means the program needs another sample or diagnostic testing.

The American Academy of Pediatrics recommends the first office follow-up at 3–5 days of age and within 48–72 hours after discharge. The visit usually covers weight, jaundice, feeding, hydration, stool and urine, the umbilical cord, safe sleep, and the family’s questions. Earlier follow-up may be needed after early discharge, prematurity, significant weight loss, or jaundice.

How often should a newborn eat?

Breastfed newborns commonly feed 8–12 times in 24 hours, sometimes in clusters. Offer a feed at early hunger cues—rooting, bringing hands to the mouth, or turning toward touch—instead of waiting for crying. If you use formula, follow the preparation instructions exactly and ask your pediatrician to set amounts around birth history, weight, and growth rather than a generic ounces-by-age chart.

No single feeding length proves intake. Audible swallowing, increasing wet diapers, alert periods, and the weight trend belong in the same picture. Call your pediatrician the same day for painful latch, trouble coordinating suck-swallow-breathe, repeated vomiting, a baby too sleepy to feed, or a sharp drop from the usual diaper pattern. Many newborns regain birth weight around two weeks; lack of regain by three weeks needs assessment rather than home guesswork.

Weight loss and jaundice: watch the direction

Some weight loss after birth is expected, but a percentage should never be interpreted by itself. Timing, milk transfer, diapers, gestational age, jaundice, and the physical exam all matter. Your pediatrician may arrange a sooner recheck or feeding support if the loss is approaching 8–10%, continues, or comes with other concerns.

Jaundice that appears in the first 24 hours needs same-day medical assessment. Call your pediatrician promptly if yellowing spreads or deepens, your baby becomes hard to wake or feeds poorly, urine is dark, stools are pale or chalky, or wet diapers fall off. Sunlight through a window is not a substitute for bilirubin measurement or prescribed phototherapy.

Newborn sleep is fragmented—and highly trackable

Newborn sleep is spread across day and night. There is no medically established minute-perfect wake-window schedule for the first 28 days, and one day may look nothing like the next. That makes personal history especially valuable: consistent logging shows how feeding and sleep connect, which stretch of night is lengthening, and how your baby’s own awake intervals are changing. As the record grows, Nerumi turns that history into increasingly useful personal sleep estimates.

Place your baby on their back for every sleep on a firm, flat, separate surface with no pillows, positioners, toys, bumpers, or loose bedding. Room-sharing without bed-sharing is recommended. Skin-to-skin contact is valuable while the adult is awake and attentive; sleeping with a baby on a couch or armchair is particularly dangerous.

Cord care, vitamin D, vitamin K, and hepatitis B

Keep the umbilical stump clean and dry unless your maternity team gave a different plan. Fold the diaper below it and avoid powders, oils, or home remedies. Call your pediatrician for spreading redness, pus, bad odor, fever, or bleeding that does not stop. A sponge or brief bath is fine if the stump is dried afterward; you do not need to wait for a particular “fall-off day.”

Vitamin K is normally given after birth to prevent vitamin K deficiency bleeding. The AAP recommends 400 IU of vitamin D daily beginning in the first days for fully or partly breastfed infants, continuing until daily formula intake reaches about 32 ounces; follow your pediatrician’s instructions. US hepatitis B guidance changed in December 2025: when the mother tested negative, timing of the birth dose is now an individual decision with the pediatrician. If the mother tested positive or her status is not available, time-sensitive birth protection remains essential. Record the actual plan rather than relying on an old online calendar.

When should you call the pediatrician right away?

A rectal temperature of 100.4°F (38°C) or higher in a baby under three months means calling your pediatrician immediately; do not give fever medicine before the pediatrician advises it. Call 911 for severe breathing difficulty, blue or gray lips or skin, a seizure, or an unresponsive baby. Seek urgent medical care for grunting or chest retractions, a baby who cannot be woken to feed, green vomit, repeated projectile vomiting, rapidly worsening jaundice, very pale stools, or a marked fall in urine.

Call your pediatrician the same day for spreading redness around the cord, painful or ineffective feeding, persistent concern about weight, or any change that makes your baby look distinctly unlike themselves. Parental recognition of a newborn’s change is clinically useful information.

Vaccinations

United States

For babies born to mothers who tested negative for hepatitis B, vaccine timing is a shared decision with the clinician; if the birth dose is not given, the current schedule shows the first dose at 2 months. If the mother tested positive or her status is unknown, vaccination at birth and, when indicated, hepatitis B immune globulin are time-critical and follow a separate high-risk plan. Use the birth record and the baby's clinician-led plan.

This schedule is for reference. Which vaccine your child needs and when is your doctor's call.

Schedule: U.S. HHS / CDC · US-HHS-2026-01 · reviewed 2026-08-25