{"id":16325,"date":"2026-06-01T08:17:00","date_gmt":"2026-06-01T08:17:00","guid":{"rendered":"https:\/\/petitmaxou.com\/?p=16325"},"modified":"2026-08-07T17:48:22","modified_gmt":"2026-08-07T16:48:22","slug":"baby-grobag","status":"publish","type":"post","link":"https:\/\/petitmaxou.com\/en\/blog\/grenouillere-bebe\/","title":{"rendered":"Baby sleepsuit: complete guide (size, material, fastening)"},"content":{"rendered":"<p>There <strong>baby grow<\/strong> is the most worn clothing item in the first months of life. Every baby has several \u2014 but choosing the right one involves understanding the differences in format, material, fastening and size. This complete guide helps you kit out baby wisely from birth to 18 months. \ud83d\udc38<\/p>\n<h2>\ud83d\udd0d What is a baby grobag?<\/h2>\n<p>A sleepsuit (also known as baby pyjamas, a onesie or a sleepsuit) is a one-piece garment that covers a baby\u2019s entire body, from the feet right up to the neck. It differs from the bodysuit in that it has long legs with integrated feet. It is the standard night-time garment for infants and babies up to 18\u201324 months.<\/p>\n<h2>\ud83d\udc76 The different types of baby grows<\/h2>\n<h3>The classic footed sleepsuit<\/h3>\n<p>The most common format: it covers the whole body including the feet. Ideal for the night as it prevents baby from uncovering themselves. Non-slip feet are very useful as soon as baby starts to stand up.<\/p>\n<h3>The double-zip sleepsuit<\/h3>\n<p>Much appreciated innovation: a two-way zip. For night-time nappy changes, opening only the bottom part avoids having to undress baby completely \u2014 essential to avoid waking them up fully at 3 am.<\/p>\n<h3>The footless babygrow<\/h3>\n<p>More versatile, it makes it possible to add booties depending on the temperature. Practical in summer or as daywear.<\/p>\n<h3>The magnetic all-in-one pyjama<\/h3>\n<p>Magnetic fasteners allow for silent and ultra-fast dressing, even in the dark. Ideal for parents changing baby at night without turning on the light.<\/p>\n<h2>\ud83e\uddf6 Which material should I choose?<\/h2>\n<h3>OEKO-TEX certified organic cotton<\/h3>\n<p>The ultimate standard for delicate infant skin. Soft, breathable, hypoallergenic, free from chemical residues. The top choice for sensitive skin.<\/p>\n<h3>interlock cotton<\/h3>\n<p>Thicker and softer knit than standard jersey. Slightly warmer \u2014 ideal for transitional seasons. Resistant to repeated washing.<\/p>\n<h3>Soft velour \/ lightweight fleece<\/h3>\n<p>For winter nights: provide superior warmth. To be worn with a sleeping bag with a TOG rating suitable for the room temperature.<\/p>\n<h3>Bamboo<\/h3>\n<p>Ultra-soft, thermoregulating, antibacterial. Particularly recommended for babies who sweat easily or have eczema-prone skin.<\/p>\n<h2>\ud83d\udcd0 What size babygrow should I choose?<\/h2>\n<p>Babygrows often run slightly small \u2013 the built-in feet limit how long they can be worn. When in doubt, always size up.<\/p>\n<ul>\n<li><strong>Birth (50 cm)<\/strong> up to 3.5 kg \u2014 range 2-3 weeks maximum<\/li>\n<li><strong>1 month (56 cm)<\/strong> up to 4-5 kg<\/li>\n<li><strong>3 months (62 cm)<\/strong> first really useful purchase<\/li>\n<li><strong>6 months (68 cm)<\/strong> : litter 2-3 months old<\/li>\n<li><strong>9 months (74 cm)<\/strong> : litter 2-3 months old<\/li>\n<li><strong>12 months (80 cm)<\/strong> : range 3-4 months<\/li>\n<li><strong>18 months (86 cm)<\/strong> latest sleepsuit size for most children<\/li>\n<\/ul>\n<h2>\ud83c\udf21\ufe0f Sleepsuit and temperature: the right combination<\/h2>\n<p>The romper suit should not be worn on its own in cool weather \u2014 it should be worn with a sleeping bag. The principle is: a lightweight romper suit + a sleeping bag suitable for the season\u2019s TOG rating. Never use a blanket over the top before 12 months.<\/p>\n<ul>\n<li><strong>Room &gt; 24\u00b0C<\/strong> ultra-thin babygrow alone<\/li>\n<li><strong>Room 20-24\u00b0C<\/strong> : cotton romper + sleeping bag TOG 1<\/li>\n<li><strong>Bedroom 16-20\u00b0C<\/strong> : cotton romper + sleeping bag TOG 2.5<\/li>\n<li><strong>Room &lt; 16\u00b0C<\/strong> : warm romper + sleeping bag TOG 3.5<\/li>\n<\/ul>\n<h2>\ud83c\udf19 Babygrow or two-piece pyjamas?<\/h2>\n<p>Before 18 months, the babygro is recommended: it doesn't come undone and doesn't ride up during the night. The two-piece pyjamas present the risk that the top rides up and exposes the baby's tummy. The babygro maintains an even layer over the whole body, which paediatricians recommend to prevent nighttime chilling.<\/p>\n<p>From around 18-24 months, when the child is more independent and starts undressing on their own, two-piece pyjamas can gradually take over.<\/p>\n<h2>\ud83d\udca1 The practical criteria often forgotten<\/h2>\n<ul>\n<li><strong>The closure<\/strong> two-way zip for night-time changes \u2014 essential<\/li>\n<li><strong>The neckline<\/strong> : wide or with shoulder poppers for newborns (no difficult head-opening)<\/li>\n<li><strong>The non-slip feet<\/strong> check that the pimples do not rub off after 3 washes<\/li>\n<li><strong>Flat or external seams<\/strong> to prevent irritation on baby's delicate skin<\/li>\n<li><strong>CE and OEKO-TEX certification<\/strong> : essential for any clothing in direct contact with the skin<\/li>\n<\/ul>\n<h2>\ud83e\uddfa How many baby grows should I plan for?<\/h2>\n<p>Allow for 5 to 7 babygrows per size. Night-time messes (spit-up, nappy leaks) often mean changing baby during the night. With 6 babygrows, you have some leeway even if the washing takes a day. Focus your purchases on 3 months and 6 months \u2014 the newborn size is worn for a very short time.<\/p>\n<h2>\u267b\ufe0f Caring for and passing on the baby grow<\/h2>\n<ul>\n<li><strong>Wash at 40\u00b0C<\/strong> keeps the colours and zips<\/li>\n<li><strong>No fabric conditioner<\/strong> on organic cotton and bamboo \u2014 it reduces the effectiveness of breathable fibres<\/li>\n<li><strong>Air drying<\/strong> preserves the elasticity and softness of the fabric<\/li>\n<li><strong>The regurgitation stains<\/strong> treat them immediately with Marseille soap before washing<\/li>\n<\/ul>\n<p>A well-cared-for organic cotton babygrow can last two or three children. That is yet another reason to invest in quality rather than quantity.<\/p>\n<p>To dress baby consistently, also find our guide on <a href=\"https:\/\/petitmaxou.com\/en\/blog\/bodysuit-baby-guide\/\">the bodysuit baby<\/a> \u2014 the essential base layer to be worn under the sleepsuit in cool weather \u2014 and our advice on <a href=\"https:\/\/petitmaxou.com\/en\/blog\/how-to-dress-baby-in-summer\/\">dressing baby in summer<\/a>.<\/p>\n<h2>\u2753 FAQ \u2014 Baby sleepsuit<\/h2>\n<h3>Can you put a baby in a babygro during the day?<\/h3>\n<p>Yes, especially in the first few months. Rompers aren\u2019t just for night-time \u2014 lots of parents dress their babies in rompers all day long. From 3\u20134 months onwards, you can mix things up a bit more with daytime outfits (size bodysuit + trousers, playsuits).<\/p>\n<h3>Should you put a bodysuit under the romper?<\/h3>\n<p>In cool weather (room temperature &lt; 20\u00b0C): yes, a short- or long-sleeved bodysuit provides an extra layer of warmth. In hot weather (room temperature &gt; 22\u00b0C): the romper on its own is sufficient.<\/p>\n<h3>Is the footed sleepsuit uncomfortable for walking?<\/h3>\n<p>Not if the size is right. A babygrow that is too short and pulls on the feet can hinder hip development. Always make sure the feet have room and that the crotch is not too tight.<\/p>\n<h3>A romper or a sleep sack: which should you choose for the night?<\/h3>\n<p>The two complement each other. The sleepsuit is the night-time garment. The sleep sack (or sleeping bag) is the blanket worn over it. Together, they make up the ideal night-time outfit according to French paediatric recommendations.<\/p>\n<h2>\ud83d\udecd\ufe0f Baby rompers at PetitMaxou<\/h2>\n<p>Soft cotton rompers, double-zip designs, adorable patterns and OEKO-TEX-certified fabrics: PetitMaxou offers a comfortable and practical range for your baby\u2019s first few months. Free delivery throughout the EU, returns within 14 days.<\/p>\n<p><a href=\"https:\/\/petitmaxou.com\/en\/product-category\/clothing\/\">\u2192 See all PetitMaxou baby rompers and baby clothes<\/a><\/p>\n<h2>\ud83c\udf81 Baby sleepsuit: the ideal newborn gift<\/h2>\n<p>A set of 3 to 5 organic cotton baby grows in a pretty box is one of the <strong>most popular new baby gifts<\/strong> \u2014 immediately useful, used daily, and often not thought of by parents-to-be who focus on the big items (pushchair, cot). If you are looking for other ideas to complete your gift, our selection of <a href=\"https:\/\/petitmaxou.com\/en\/blog\/original-baby-gift\/\">original newborn gifts<\/a> is a good source of inspiration. Choose 3-month size rather than newborn \u2014 the newborn size is worn for a very short time and often already received in triplicate.<\/p>","protected":false},"excerpt":{"rendered":"<p>La grenouill\u00e8re b\u00e9b\u00e9 est la pi\u00e8ce vestimentaire la plus port\u00e9e dans les premiers mois de vie. Tout b\u00e9b\u00e9 en poss\u00e8de plusieurs \u2014 mais choisir la bonne implique de comprendre les diff\u00e9rences de format, de mati\u00e8re, de fermeture et de taille. Ce guide complet vous aide \u00e0 \u00e9quiper b\u00e9b\u00e9 intelligemment de la naissance \u00e0 18 mois. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":16324,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[228],"tags":[],"class_list":["post-16325","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-conseils"],"acf":[],"_links":{"self":[{"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/posts\/16325","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/comments?post=16325"}],"version-history":[{"count":0,"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/posts\/16325\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/media\/16324"}],"wp:attachment":[{"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/media?parent=16325"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/categories?post=16325"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/petitmaxou.com\/en\/wp-json\/wp\/v2\/tags?post=16325"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}