Let's start off with some very basic and intuitive safety tips to keep in mind when using a baby carrier. The first is via a babywearing safety acronym titled T.I.C.K.S.
One key safety consideration is how securely baby is carried. A fall from chest height is very dangerous for a baby. Baby should be closely held to the parent, and young babies should be provided a high back that fully supports baby's head and neck.
If you are new to baby wearing, or just started with a new type of carrier, take time to learn how to use it appropriately to ensure that baby is positioned both closely and securely inside. We recommend keeping one or two hands on baby at all times until you get used to a carrier, and are certain that all buckles and ties are secure. Over time, as you get comfortable with the carrier, you'll be able to have one or both hands free.
Until baby's neck is strong enough to hold its head up on its own, baby's head and neck should be properly supported. This milestone typically occurs around four months of age. Do not attempt a front carry facing out position until baby has the strength to comfortably hold up their head on their own. Most babies younger than this are usually content being snuggled facing in right up against mom or dad's chest anyway.
A back carry position offers reduced support for baby, and the parent can't see what is going on with baby. As a result, back carry positions are not recommended until baby is a bit older, at least 6 months old, and many parents use front carry positions exclusively until baby is a toddler, which we feel is wise.
Frequent care should always be taken with regard to maintaining an infant's airway in any baby carrier. Use extra care with infants under 4 months old and babies with colds or respiratory problems. Baby's face should be visible to you when baby wearing and head close enough to kiss. Be certain that their airway is never obstructed, either by your body or the carrier itself. Baby's nose and chin should be clear of fabrics and positioned comfortably keeping baby's chin away from touching its chest slightly extended, at least least two adult finger widths. Until baby has good head and neck control, positioning its head turned to one side or the other with cheek resting against the chest while in the front carry facing in position (that is, facing the parent) can help avoid this airway compromising chin to chest position. Several sling type carriers have been recalled in the last few years because when used incorrectly, they can pose a suffocation hazard to young infants.
One thing you'll notice when your pediatrician examines your newborn, is that they will perform a test of baby's hips. What they are looking for is symptoms of hip dysplasia, which is a fairly common development issue. The International Hip Dsyplasia Institute is a good source of information on how positional care in baby wearing can make a big difference in creating healthy hips. They also cover related topics such as proper swaddling, and guidelines for car seats.
Most hip development issues occur in the first 4 months of a newborn's life. Thus, special care should be taken with young babies. Baby wearers should allow for frequent breaks from the carrier so that baby can move its hips, knees, and the rest of the body around freely.
The hip joint is commonly referred to in medical jargon as a “ball and socket joint,” meaning the superior portion of the femur called the femoral head has a rounded shape like a ball which fits neatly into the rounded cup-shaped area of the pelvis called the acetabulum. At birth, a large portion of a newborn's partially developed hip joint is comprised of soft cartilage. The above illustration from The International Hip Dysplasia Institute highlights the key difference between the basic anatomy of an infant's hip compared to an adult's hip. Additionally, inside the womb and upon birth, newborn's joints are flexible and lax, the hips being especially prone to dislocating. Certain factors such as a family history of hip dysplasia or breech positioning, increase the risk of an infant having developmental hip dysplasia. However, chronic poor positioning in the first 4-6 months of life, can be a leading contributor as well. By 4-7 months of life, a large portion of this cartilage has turned to bone, increasing hip stability greatly.
In addition, sling-type carriers have been called out as potentially risky for hip development, if the baby's legs are in a straight position (see illustration below from the International Hip Dysplasia Institute).
We understand the perspective of many passionate sling fans, and it is certainly the case that by paying attention to the safety tips, many parents have safely used and enjoyed wearing their baby in a sling. However, given these two risks, we do not recommend sling-type carriers for babies in the newborn to 4 months age range.