Baby nappies: how do you choose? Two criteria matter more than the brand. The size is set by weight and by what your baby’s skin shows, and the composition is judged first of all by the absence of fragrance. That is the clearest recommendation from Anses, the French Agency for Food, Environmental and Occupational Health and Safety, which assessed the safety of disposable nappies in 2019.
A baby uses several thousand nappies before being potty trained. So the choice is made hundreds of times over, and every mistake shows quickly: leaks, redness, marks from the elastics. This guide covers the practical criteria, then what public experts have established about chemical substances.
Baby nappies: how do you choose the right size?
A nappy size does not correspond to an age but to a weight range, shown on every pack. These ranges vary from one brand to another and overlap from one size to the next. A 6 kg baby might therefore wear a size 2 or a size 3, depending on the manufacturer and their build.
Weight gives you a starting point, not a rule. A baby with chubby thighs will feel tight in a size that suits a long, slim baby of the same weight. So the right fit is checked on your child, nappy after nappy.
Signs that a nappy is too small
- Red, indented marks at the waist or the tops of the thighs that are still there after the change.
- Frequent leaks out of the top, up the back, especially after a poo.
- Tabs that pull and only fasten at the very edge of the fastening strip.
- A nappy that is soaked well before the usual changing time.
Signs that a nappy is too big
- Leaks at the sides, around the thighs, when your child is lying on their side.
- Fastening tabs that almost cross over in the middle.
- A visible gap between the elastics and the skin, where two fingers slip in easily.
A good fit lets one finger slide under the waistband, no more. The leg elastics should be pulled outwards, otherwise they don’t hold well. This simple step solves a good share of the leaks wrongly blamed on the size.
Should you buy big packs in advance?
Not in the first few months. A newborn changes size within a few weeks, and too large a stock becomes unusable. It’s better to buy small quantities while growth is fast, then switch to bulk packs once the size settles, often after six months.
What Anses found in disposable nappies
In January 2017, an investigation published by a consumer magazine reported chemical residues in baby nappies. The French ministries of Health and the Environment and the DGCCRF, France’s consumer protection and anti-fraud authority, then referred the matter to Anses. The agency issued a revised opinion on 17 January 2019.
Public laboratories and the Institut national de la consommation, France’s National Consumer Institute, analysed 23 disposable nappy products sold in France. They detected several families of substances:
- fragrances, deliberately added by some manufacturers;
- polycyclic aromatic hydrocarbons, or PAHs, found mainly in the elastics;
- dioxins, furans and so-called “dioxin-like” PCBs;
- pesticide residues, including glyphosate, as well as formaldehyde and volatile organic compounds.
According to Anses, most of these substances are not added intentionally. They are thought to come from contaminated raw materials or from manufacturing processes such as bleaching or gluing. Fragrances are the exception: they are added deliberately.
A risk that cannot be ruled out
Anses carried out a quantitative risk assessment for skin contact, using assumptions it considers realistic. It concluded that health thresholds are exceeded for certain substances: two fragrances, lilial and lyral, certain PAHs, PCB-126 and the sum of dioxins, furans and dioxin-like PCBs. For the other fragrances, glyphosate, VOCs and formaldehyde, no exceedance was found.
The agency points out that no epidemiological data link wearing nappies to health effects. It nevertheless writes that “it is not possible to rule out a health risk linked to wearing disposable nappies”. It recommends eliminating these substances or reducing them as far as possible, following the “as low as reasonably achievable” principle.
What happened next
In March 2020, Anses published threshold concentrations for each substance, to help manufacturers and authorities set limits. The same year, it prepared a proposal for a Europe-wide restriction under the REACH regulation, covering PAHs, dioxins, furans, PCBs and formaldehyde. A public consultation was opened by the European Chemicals Agency from 15 January to 31 March 2020.
There is still no regulation specific to baby nappies: they fall under the general product safety obligation. The information on the pack therefore remains a parent’s main tool.
Composition: the criteria that really matter
Choose a fragrance-free nappy
This is the only criterion Anses states so directly: it recommends removing all fragrances, starting with those that can sensitise the skin. A fragrance-free nappy smells of nothing. A nappy that smells “nice” almost always contains added fragrance, however subtle.
Check what the pack says about bleaching
Dioxins and furans can form during chlorine bleaching. Anses mentions alternative processes using oxygen or hydrogen peroxide. Some packs state chlorine-free bleaching, which is in line with its recommendations.
Don’t read too much into marketing claims
Claims such as “natural”, “eco-friendly” or “dermatologically tested” do not guarantee the absence of the substances detected. Anses found contaminants both in standard products and in products sold as eco-friendly. A reputable environmental label tells you about materials and processes, not about a test result.
Disposable or reusable nappies: which should you choose?
Reusable nappies avoid the substances linked to manufacturing disposables, but they require a washing routine and an upfront investment. Our guide to getting organised with reusable nappies covers how many you need, drying and care. Many families mix the two: reusables at home, disposables at night or when out and about.
The same reasoning applies to changing. Reusable wipes and water are enough in most cases and cut down on the products applied to the skin.
How many nappies a day, and how often should you change them?
A newborn wets their nappy very often and poos frequently: you can usually expect eight to twelve changes a day in the first weeks. The pace then slows, to around five to eight changes a day after a few months.
There is no official maximum wearing time. The useful rule of thumb is simple: change after every poo, and as soon as the nappy feels heavy. Prolonged moisture and friction are the main causes of redness. If it appears anyway, our article on nappy rash in babies sets out what the health authorities recommend.
When should you move from nappies to pants, then to the potty?
Nappies have no fixed end date. A child becomes potty trained when they feel the urge and can hold it, usually between 2 and 3 years old. Training pants are an in-between step that only helps some children: our guide to training pants will help you decide.
When the time comes, a convertible potty that turns into a toilet seat reducer and a step stool sees you through each stage without buying three separate items. Our dedicated potty training selection brings this equipment together. For everyday care, our guide on how to clean a baby potty avoids harsh products, in the same spirit as for nappies.
Key takeaways
- Choose the size by the weight shown on the pack, then adjust it according to marks on the skin and leaks.
- One finger under the waistband, leg elastics pulled out: this fit sorts out a lot of leaks.
- Since 2019, Anses has recommended removing fragrances from nappies: go for a fragrance-free nappy.
- A risk linked to certain substances cannot be ruled out, though no health effect has been demonstrated to date.
- Change after every poo and as soon as the nappy feels heavy.
Sources
- Anses, “Sécurité des couches pour bébé”, revised opinion and collective expert appraisal report, request no. 2017-SA-0019, 17 January 2019.
- Anses, revised scientific and technical support note on the presence of chemical substances in single-use baby nappies, request no. 2019-SA-0076, 9 March 2020.
- Anses, “Disposable nappies: consultation with stakeholders regarding the Europe-wide restriction of chemicals that are harmful to babies' health”, 15 January 2020.
