There is no age gap between two children that is right for everyone. There is, however, a health benchmark: the World Health Organization recommends waiting at least 24 months after a birth before conceiving again, which works out at roughly three years between two births. And there is the reality in France: according to INED (the French Institute for Demographic Studies), the average gap between the first and second child is 4.2 years. Between these two figures, every family weighs up the mother's health, age, work, housing and the energy available. Here is what you need to make an informed decision.
What age gap between two children does the WHO recommend?
The recommendation comes from a WHO technical consultation held in Geneva in June 2005, whose report was published in 2007. After a live birth, the experts recommend an interval of at least 24 months before trying for another pregnancy. The aim is to reduce the risk of adverse outcomes for the mother, around the time of birth and for the baby. After a miscarriage or a termination of pregnancy, the recommended interval is at least 6 months.
The report is open about its limitations. The experts were divided between 18 and 27 months, and 24 months was chosen as a compromise, consistent with the recommendation to breastfeed up to the age of two and simpler to communicate. The 6-month recommendation after a miscarriage rests on a single Latin American study, and the report advises treating it with caution. The data date from 2005 and come mostly from countries where access to healthcare differs from ours. To our knowledge, no French health authority has published a separate recommendation with a specific figure on this point.
This interval is counted from the birth to the start of the next pregnancy, not between two births. Twenty-four months on that side therefore corresponds to an age gap of about 33 months between the two children.
Why does a short interval increase the risks?
According to the same report, an interval of 6 months or less between a birth and the next pregnancy is associated with a higher risk of maternal death. An interval of about 18 months or less is associated with a higher risk of infant, neonatal and perinatal death, low birth weight, being small for gestational age and premature birth. Between 18 and 27 months, some residual risk is possible, but the data available at the time did not allow it to be quantified.
The mechanisms put forward are the incomplete recovery of the mother's body after a pregnancy and breastfeeding, and the strain of caring for a toddler during the following pregnancy. These are statistical associations at population level, not certainties for any given family. A closely spaced pregnancy calls for monitoring, not condemnation. The official figures on premature birth are set out in our article on premature birth in France.
What is the average age gap between two children in France?
INED answered this question in a note published on 8 September 2025: the average gap between the first and second child is 4.2 years, compared with 4.1 years in 2013. Between the second and third, it was 4.8 years in 2023, 0.3 years more than in 2013. So these gaps are barely increasing. What is changing is the mother's age at her first child, which rose from 26.5 in 1977 to 29.1 in 2023 according to Insee (the French national statistics office). It is the first child that is being postponed; the next ones then follow at a steady pace.
In other words, the typical French family leaves far more than the WHO's 33 months between two births. Gaps of under two years do exist, but they are in the minority. A parent considering an 18-month gap is therefore not doing ‘what everyone does’: it is a choice worth discussing with the midwife or doctor looking after the mother.
A small gap, under two years: what it means day to day
- Two children who are not yet independent at the same time. An 18-month-old has not been walking for long, cannot dress alone, is still in nappies and naps in the afternoon. At times the logistics resemble those of a family with twins, which we describe in getting organised with twins.
- Equipment still in use. The cot, high chair, car seat and pushchair are still being used by the older child. You will need to double up on some items or choose convertible solutions: a double pushchair, the next-stage car seat for the older child, a spare bed.
- A pregnancy with a toddler in your arms. Carrying, broken nights and a strained back take their toll on a mother who has not finished recovering.
- A genuine closeness between the two. At three or four, the two children often play together and share the same activities and daily routine. The older child's jealousy is there but takes a different form: they do not understand what is happening and react physically, regression included.
A large gap, four years or more: advantages and limits
- An independent older child. They are potty trained, eat by themselves, go to school in the morning and understand what you explain to them. The baby's first three months are noticeably easier as a result.
- Equipment freed up. Everything used for the first child is available again, provided you kept it. A play mat, a baby bouncer or a baby bath in good condition can be reused without any problem, and we explain what is worth keeping in our article on the budget for the first year. Standards do change, though: an old car seat or a bed that no longer meets the rules should be replaced.
- Two different rhythms of life. School trips, activities, the baby's naps and school hours do not line up. For several years, the two children have neither the same needs nor the same games.
- A more verbal jealousy. The older child can say they disagree, which makes it both easier to hear and harder to ignore.
- The parents' age. Putting off the second child moves the pregnancy towards ages when fertility declines and certain risks increase. It is one factor to weigh up, not a deciding argument.
Practical questions to sort out, whatever the gap
Maternity leave and childcare
A closely spaced second pregnancy may come before the end of parental leave or just after returning to work. In France, the length of maternity leave depends on the number of children already in the household: from the third child onwards, it is longer. We explain these rules in our article on the length of maternity leave. As for childcare, a small gap raises the question of finding places for two children in the same setting, something to plan very early.
The day of the birth
Who looks after the older child during the birth is a question that arises from the second child onwards, and it gets trickier when they are under two. We covered it in detail in childcare for your older child during the birth.
The bedroom
A small gap often means both children sleep in the same room, which is only an option once the baby has reached a certain age and with strict safety rules. We set them out in baby and older sibling in the same room.
Equipment
With a large gap, the older child has finished with their play mat, bath and potty, and these pass to the younger one. With a small gap, a single 150 × 200 cm play mat fits both children at once, the baby on their back on one side and the older child playing on the other. How long this kind of equipment really lasts, from one child to the next, is covered in our guide to how long a play mat is used.
Preparing the older child, whatever their age
An 18-month-old is not prepared with words but with routines. You let them touch the bump, show them babies, and change nothing important in the weeks before the birth. A four-year-old is prepared by talking, by involving them in a few choices and by keeping some time just for them after the baby arrives. We have gathered these pointers in our article on preparing your older child for the arrival of a second baby.
Key takeaways
There is no ideal age gap between two children. The WHO recommends at least 24 months between a birth and the next pregnancy, for maternal and child health reasons that are documented but not recent. French families leave an average of 4.2 years between their first two children. A small gap calls for an organisation close to that of twins; a large gap frees up equipment and gives you an independent older child, but spreads the early-childhood years out. In every case, it is the mother's health that decides, together with the professionals caring for her.
Sources
- WHO, “Report of a WHO Technical Consultation on Birth Spacing”, Geneva, 13-15 June 2005, reference WHO/RHR/07.1, published in 2007. Read on the Reproductive Health Supplies Coalition website.
- INED, “Le délai entre les naissances augmente-t-il?”, question of the day, 8 September 2025.
- Insee, Jeanne Pointet, “Un premier enfant à 29,1 ans en 2023: un âge qui continue d'augmenter”, Insee Focus No. 356, July 2025, cited by INED.
