Size 0M or 1M? How to choose the right clothes for your baby
One of the most common doubts during pregnancy is:
should I buy 0M clothes or go straight to 1M?
With so many opinions — including from health professionals — it’s normal to feel confused. In this guide, we explain simply how to choose the right size for your baby.
What does size 0M mean?
Size 0M (newborn) is designed for babies from birth, usually about 47 to 50 cm, according to average standards.
👉 In practice, it is the ideal size for:
- first days
- leaving the maternity ward
- first weeks of life
How long does the baby wear 0M?
It depends on the baby, but on average:
Standard chart from World Health Organization (WHO)
- Babies within the average percentile → wear 0M for 3 to 4 weeks
- Bigger babies → can wear for less time
- Smaller babies → can wear for longer
💡 Every baby is unique — there is no universal rule.
And what about size 1M?
Size 1M is indicated for slightly bigger babies, usually:
- above 50–51 cm
- with faster growth
👉 It may make sense to start with 1M if:
- parents are tall
- pregnancy goes beyond 40 weeks
- exists Gestational diabetes
- there is an indication of a baby above average
So, should I buy 0M or 1M?
👉 The safest answer is:
Yes, you should have at least some pieces in 0M.
Even if the baby is bigger, 0M:
- ensures a better fit in the first days
- avoids loose and uncomfortable clothes
- makes things easier in maternity
This chart, although for boys, the measurements for girls are similar at these ages. Source: Food and Nutrition Technical Assistance - USA
So, should I buy 0M or 1M?
👉 The safest answer is:
Yes, you should have at least some pieces in 0M.
Even if the baby is bigger, 0M:
- ensures a better fit in the first days
- avoids loose and uncomfortable clothes
- makes things easier in maternity
Why is there so much confusion about sizes?
Unfortunately, there is no universal measurement between brands.
- a 0M can vary quite a bit
- some “0–3 months” sizes are inconsistent
- each brand has its own cut and model
👉 That’s why it’s important to choose brands with clear measurements designed for the real baby.
Practical tip to avoid mistakes
✔️ Have:
- 2–3 sets in 0M
- the rest in 1M
If your baby is eventually born smaller than expected, reinforce 0M after birth.
👉 This way you are prepared for any scenario.
If you have doubts, ask for help
Choosing the right size makes all the difference in your baby's comfort.
👉 If you need help, talk to us — we will be happy to advise you.
Conclusion
Between 0M and 1M, there is no single answer — but there is a smart choice.
Preparing some pieces in 0M is the safest way to ensure comfort in the first days, while 1M ensures continuity in the following weeks.
The most important thing is to choose clothes that respect your baby's body from the very first moment.