The newborn (neonatal) stage lasts 28 days. According to the NHS Data Dictionary, the neonatal period begins on the date of birth and ends 28 completed days later. That first month is a distinct phase with its own set of health checks, feeding patterns, and physical changes that differ from the broader “infant” stage that follows.
Those four weeks are packed with rapid development and a steep learning curve for parents. Here’s what to expect during each part of the newborn period.
Health Checks in the First Week
Two major screenings happen before your baby is even a week old. The first is the Newborn and Infant Physical Examination (NIPE), which should be completed within 72 hours of birth. This checks four specific areas: your baby’s eyes, heart, hips, and (if applicable) testes. It’s typically done before you leave hospital, or by a midwife shortly after a home birth.
The second is the newborn blood spot test, commonly called the heel prick test, done when your baby is 5 days old. A small blood sample from the heel screens for 10 rare conditions, including cystic fibrosis, sickle cell disease, and congenital hypothyroidism. Most results come back clear, but early detection of these conditions can be life-changing because treatment works best when started in infancy.
Weight Changes in the First Two Weeks
Almost all newborns lose weight in the first few days after birth. This is normal and expected. Around 80 percent of babies regain their birth weight by two weeks of age. A loss of up to about 10 percent of birth weight is considered the upper limit of normal. If your baby loses more than that, or is slow to regain weight, your midwife will want to assess feeding and check for other issues.
Your midwife will weigh your baby regularly in these early days, so you won’t need to guess whether things are on track.
Feeding Patterns and What’s Normal
Breastfed newborns typically feed 8 to 12 times in 24 hours, roughly every 2 to 4 hours. That frequency can feel relentless, but newborn stomachs are tiny and breast milk digests quickly. Formula-fed babies may go slightly longer between feeds, though the total number of feeds per day is often similar in the early weeks.
One of the easiest ways to tell whether your baby is getting enough milk is by counting wet and dirty nappies. On day one, expect just 1 to 2 wet nappies. By days 2 to 3, that rises to 2 to 4. From day 4, you should see 4 to 6 wet nappies, and from day 5 onward, 6 or more. You should also see at least 3 to 4 dirty nappies a day by the time your baby is 4 days old. A drop in nappy output can be an early sign that feeding needs attention.
Sleep During the Newborn Stage
Newborns sleep a lot, typically 16 to 17 hours per day, but never for long stretches. Most will sleep only 1 to 2 hours at a time before waking to feed. There’s no real difference between day and night for a newborn; their internal clock won’t start to develop until closer to 6 to 8 weeks. This is one of the hardest parts of the newborn stage for parents, and it’s completely normal. By the end of the 28-day period, some babies begin to have slightly longer stretches of sleep at night, though this varies widely.
The Umbilical Cord Stump
Your baby’s umbilical cord stump will dry out and fall off between 5 and 15 days after birth. Until it does, keep the area clean and dry. Fold the nappy down below the stump so air can circulate. Signs of infection include foul-smelling yellow discharge, or redness, swelling, or tenderness of the skin around the stump. If your baby also develops a fever (38°C or higher), poor feeding, or seems floppy and lethargic, that needs urgent medical attention.
Jaundice in the First Weeks
Jaundice is very common in newborns. It shows up as a yellow tinge to the skin and the whites of the eyes, often starting on the face and head before spreading. It’s usually caused by the baby’s liver still maturing and struggling to clear a substance called bilirubin from the blood. In most cases it’s mild and resolves on its own.
You can check for jaundice by gently pressing on your baby’s nose or forehead in bright or natural light. If the skin looks yellow when you release, mention it to your midwife. If treatment is needed, most babies receive phototherapy, a special light shone on the skin, usually in hospital for around 48 hours.
Seek urgent help if a baby with jaundice becomes sleepier than usual, stops feeding, feels unusually hot or cold, produces no wet nappies, or has difficulty breathing. In a baby under 24 hours old, any sign of jaundice should be assessed immediately.
What Changes After 28 Days
Once the 28-day neonatal period ends, your baby is medically classified as an infant rather than a newborn. In practical terms, a few things shift. Midwife visits typically wind down and your health visitor takes on a larger role. Your baby’s feeding may become slightly more predictable, and weight gain should be steady. The intense monitoring of those first four weeks eases off, though regular check-ups continue through the first year.
The newborn stage is short but dense. Almost every system in your baby’s body is adjusting to life outside the womb, and the health checks, feeding rhythms, and physical changes of those 28 days lay the groundwork for everything that follows.