The first month of a baby's life looks calm from outside and is anything but underneath. Lungs that have never breathed air are working. A heart that ran one circulation in the womb is rewiring itself for another. Temperature regulation, which mum did, is now the baby's job. Feeding, sleep, and weight all have to find their rhythm in a body that is changing day by day. Knowing what is meant to happen — and which signs are the ones that actually need a call — makes the first four weeks feel less like a guessing game.
Healthbooq covers what to expect from each NHS check and what to track between them.
What Happens in the First Hours
Three big switches flip in the first minutes after birth.
The lungs. Before birth, the lungs are full of fluid and the placenta does the gas exchange. The first breath has to clear that fluid and inflate alveoli that have never opened — which takes a much higher pressure than any later breath. This is why the first cry is biologically useful: it generates exactly that pressure.
The heart. Two fetal shortcuts close in sequence. The foramen ovale — a flap between the right and left atria — closes functionally within minutes once pulmonary blood flow rises. The ductus arteriosus — the vessel connecting pulmonary artery to aorta — usually closes within 24 to 72 hours. Persistent ductus arteriosus is one of the things the NIPE listens for.
Temperature. A newborn's surface area to body weight ratio is roughly three times an adult's. They lose heat fast and have very limited brown fat reserves to make it back. Skin-to-skin in the first hour is not just a bonding ritual — it cuts heat loss measurably and stabilises blood sugar. Hat on, room above 20°C, dry the baby thoroughly. Cold, blue hands and feet (acrocyanosis) are normal in the first 24 hours; cold trunk is not.
The Four Routine Checks
The NHS schedule across the first 28 days is consistent across England, Scotland, Wales, and Northern Ireland with minor regional differences.
Newborn and Infant Physical Examination (NIPE) — within 72 hours. A doctor, midwife, or advanced nurse practitioner runs through a top-to-toe exam focused on four screens: red reflex (cataract or retinoblastoma), heart sounds and femoral pulses (congenital heart disease, coarctation of the aorta), hips (developmental dysplasia, looking for clunks on Ortolani and Barlow tests), and in boys, descended testes. It takes about 10 minutes. The same exam is repeated at the 6–8 week GP check.
Newborn hearing screen — before discharge or within a few weeks. Two tests run automatically. AOAE (otoacoustic emissions) sends a click into the ear and listens for the cochlea's echo. If a clear response is not seen, AABR (automated auditory brainstem response) follows. Some babies fail the first test simply because of fluid in the middle ear that hasn't cleared yet — a repeat is normal, not a verdict.
Heel-prick blood spot — day 5. Five or six drops of blood from the side of the heel onto a card. It screens for nine conditions: phenylketonuria, congenital hypothyroidism, cystic fibrosis, sickle cell disease, MCAD, maple syrup urine disease, isovaleric acidaemia, glutaric aciduria type 1, and homocystinuria. Results take 6–8 weeks. Normal results are not posted out (the "no news is good news" rule); abnormal results trigger a call within days.
6–8 week GP check. Repeat NIPE plus weight, length, head circumference, and a developmental check (smiling, fixing on a face, lifting head briefly in tummy time). The first vaccinations come around the same time.
What's Normal That Sometimes Worries Parents
Almost all of the alarming-looking things in the first month are normal. Worth recognising:
- The weight dip. Up to 7% loss in the first 3 to 5 days is expected; up to 10% can be acceptable in a breastfed baby with no other concerns. Birth weight back by day 10–14. Below 10% loss, or no regain by day 14, prompts a feeding review.
- Yellow skin from day 2–3. Peaks day 4–5, gone by 10–14 days. Day 1 yellow is not normal. Yellow past 14 days needs a check.
- Stool colour shift. Black tarry meconium for 1–2 days, then green-brown transitional stools, then yellow and seedy by day 4–5 if breastfed, more pasty if formula-fed.
- Periodic breathing. Short pauses (less than 10 seconds) followed by faster breaths in healthy newborns. Up to about 6 months. Pauses over 20 seconds with colour change are not periodic breathing — that is apnoea and needs a call.
- Skin oddities. Milia (white spots on the nose), erythema toxicum (red blotches with a tiny white centre, looks like flea bites, comes and goes), Mongolian/dermal melanocytosis (slate-blue patches on the back or buttocks), newborn acne around weeks 2–4. None require treatment.
- Sneezing, hiccups, snuffly noises. Newborns sneeze a lot — it clears amniotic fluid from the nose, not a cold.
- Irregular movements. Brief jerks, trembling chin, jittery limbs when crying. Calm them by holding a limb gently — if the movement stops, it's a tremor, not a seizure. Movements that continue when you hold the limb need an assessment.
Feeding, Sleep, and Output in the First Month
By day 5 to 7, a feeding-well baby produces 6 or more wet nappies a day and at least 3 to 4 dirty nappies (breastfed; formula-fed babies often less). Feeds are roughly 8 to 12 a day in the first weeks, often clustered. Sleep totals around 14 to 17 hours but in 2 to 4 hour stretches — there is no "sleeping through" yet, and trying to engineer one usually backfires.
A breastfed baby who is feeding well: alert at the start of feeds, audible swallowing, drowsy and content after, regaining weight steadily, mum's milk visibly transitioning around day 3 to 5 from colostrum to mature milk.
When to Call
Some things in the first 28 days don't wait for the next planned visit. Same-day midwife or NHS 111:
- Fever: 38°C or higher in any baby under 3 months — this is A&E, not a wait
- Very floppy, unusually stiff, or arching backwards
- Won't wake for feeds, or refusing more than two consecutive feeds
- Fewer than 6 wet nappies a day after day 5
- Yellow skin in the first 24 hours, or yellow on the palms or soles
- Pale, putty-coloured stools or dark urine
- Persistent grunting with each breath, blue around the lips, or breathing rate over 60 a minute when calm and warm
- Fontanelle that is sunken (dehydration) or bulging when the baby is calm and upright
- A clean cord that becomes red, smelly, or oozes pus
- A bulge in the groin or scrotum that doesn't disappear when the baby is calm
Midwife and Health Visitor Handover
Midwifery care runs from birth to day 10 as a minimum and can extend to day 28 if there are any concerns about feeding, weight, or the mother's recovery. The pattern is roughly day 1 home visit, day 3–5 (often coinciding with the heel prick), and a day 10 discharge visit. The health visitor picks up around day 10–14 and continues through childhood. The handover is not a paperwork tick — it is the right moment to flag anything that has been niggling, even if you're not sure it counts.
Key Takeaways
The first 28 days carry the biggest physiological changes a human body ever goes through. Lungs take over from the placenta, the heart rewires itself in the first few days, the baby learns to keep itself warm, and feeding has to work. The NHS layers four routine checks across this period: NIPE within 72 hours, hearing screen before discharge, heel-prick blood spot on day 5, and a second NIPE at 6–8 weeks. A useful frame for parents: most things that look alarming in the first month — the weight dip, the yellow tint, the irregular breathing — are normal. The patterns to call about are specific, and worth knowing.
