Your newborn: the first month
Everything that lines up at this one age — growth figures from the WHO standard, sleep norms, the milestones whose normal window covers this month, and the vaccine doses due. Percentiles are called centiles in the UK; the numbers are identical.
Growth at 0 months
Median means half of babies are above and half below. Being away from the median is not a problem in itself — following your own curve is what matters.
| Median (50th) · Boys | Middle half (25th–75th) · Boys | Median (50th) · Girls | Middle half (25th–75th) · Girls | |
|---|---|---|---|---|
| Weight | 3.35 kg | 3.03–3.69 kg | 3.23 kg | 2.93–3.55 kg |
| Length | 49.9 cm | 48.6–51.2 cm | 49.1 cm | 47.9–50.4 cm |
| Head circumference | 34.5 cm | 33.6–35.3 cm | 33.9 cm | 33.1–34.7 cm |
Want the number for your own baby? Open the percentile calculator
Sleep at 0 months
Ranges, not targets. Healthy babies sit outside them regularly.
- Total per day
- 14 h – 17 h
- One nap
- 30 m – 2 h
- Night sleep
- 8 h – 9 h
Vaccine doses at this age
Routine doses only, from the national schedules as published by each country's health authority. Vaccinations always follow chronological age, even for premature babies.
United States
- Hepatitis Bdose 1
- RSV (nirsevimab)dose 1
Reference figures, not medical advice. Every baby differs; a check-up answers questions a table cannot.