Infant Car Seats vs. Convertible Car Seats

dad with newborn car seat

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Choosing a car seat for a newborn baby is one of the most important safety decisions a parent or guardian will make. And with seemingly countless models on the market, the choice can feel overwhelming. The safest and most effective car seat for your baby will depend upon their size and weight.

Parents have two options for newborns: rear-facing infant car seats and convertible car seats that can be used rear- and forward-facing. Each type has its benefits and drawbacks, but both are safe for young babies.

Infant Car Seat Pros and Cons

Infant-only car seats only face the rear of the vehicle and are intended for the smallest babies. Every infant car seat has its own specific weight guidelines, but they generally range from 4 to 5 pounds at the minimum and have weight limits between 30–35 pounds.

Infant car seats also have height limits. Most upper limits are between 30–55 inches. You can find specific guidelines on the seat itself, in the owner's manual, and in the American Academy of Pediatrics (AAP) online car seat product guide.

All infant car seats use a five-point harness system to keep the baby snug, secure, and comfortable when traveling in the vehicle. Most models have a base that stays in the car. This allows the parent or caregiver to secure the baby in the removable infant car seat before snapping it into place in the vehicle.

Infant Car Seat Benefits

Parents like the ease of using a rear-facing infant car seat with a snap-on base. It tends to be much easier to secure the baby in the car seat before placing it in the car, where it can be hard to get a good angle. This is also helpful in bad weather or at night when it's more difficult to see buckles and belts.

Another pro with infant car seats is additional bases can be installed in other vehicles, making it easier to switch between them. This is great for grandparents and other caregivers who travel with the baby.

Many infant-only car seats are sold as part of a travel system that comes with a stroller. The car seat has a handle parents use to carry the seat between the vehicle base and the stroller base while the baby remains safely strapped in. Because the units all fit together, travel systems take the guesswork out of trying to find the right combination of equipment.

Infant Car Seat Drawbacks

Eventually, every baby exceeds the weight and height limits on the infant car seat and must transition to a convertible all-in-one car seat. That means parents pay more to purchase two car seats instead of one. Also, as the baby grows, parents may find it cumbersome to carry them in the infant car seat instead of a wearable baby carrier or stroller.

Convertible Car Seat Pros and Cons

A convertible car seat starts off rear-facing and can be converted to forward-facing. The minimum starting weight for convertible use in the rear-facing position is not standard across all products. Some seats start at 4 pounds, many at 5 pounds, and others not until the baby reaches closer to 15 pounds. Convertible seats can typically be used rear-facing for babies 40–50 pounds.

Once they are turned to forward-facing, convertible seats can work for a child weighing 40 pounds or more. (Specific height and weight guidelines always depend on the brand and model.) They range in price for anywhere from $50 to several hundred dollars. Like infant car seats, convertible car seats have a five-point harness system that attaches at the shoulders, hips, and between the baby's legs.

Convertible Seat Advantages

Cost is a big plus with convertible car seats. Because they transition along with the baby through several stages, when starting out with a convertible car seat instead of an infant car seat, parents only have to buy one seat instead of two. They can be used from the time the baby comes home from the hospital into the toddler years, depending on the child's size.

Convertible Seat Disadvantages

Convertible car seats are generally heavier and bulkier than rear-facing only car seats. They are harder to switch from car to car and take up more space than infant car seats. They must recline to a safe angle for smaller babies, which can be a problem in smaller vehicles.

Keep in mind that just because your baby meets the manufacturer's minimum weight and height for a seat does not mean your baby will fit properly—or safely.

Choosing a Car Seat for Your Newborn

If your car seat budget allows the purchase of two car seats within a year or so, an infant-only car seat is likely to provide a better fit for most newborns. The measure of convenience these seats provide is invaluable for some parents.

Check the car seat's labels to ensure your baby fits within the weight and height guidelines for the seat you intend to buy. Once purchased, take the time to learn how to install the car seat tightly and properly. You'll need to use the manufacturer's instructions for the seat as well as your vehicle owner's manual.

Keep your child rear-facing when riding in the car until they are at least 2 years old. Most kids will become too tall for their infant seats around their first birthday, at which time they can move to a convertible seat. However, authorities like the AAP advise that kids should continue riding in rear-facing for at least another year (but ideally several more) before turning forward-facing.

Rear-facing is the safest way to ride. All infant car seats should only be used for traveling and never for eating, sleeping, or playing outside of the vehicle.

Whether you start with an infant-only car seat or a convertible car seat, the most important thing is to choose a car seat that fits your baby and your vehicle.

Inserts and Padding

Both types of infant car seats come with removable inserts to ensure a secure fit for newborns. Padding varies in terms of how effective it is at improving the fit of an infant car seat.

Placing pillows behind your baby's head almost always worsens their head position, as the pillows encourage your baby's chin to fall to their chest. Likewise, padding along the outside of the baby's chest and thighs also does not improve the fit.

What will help are infant inserts with firm padding that lift your baby up (which helps them reach the lowest set of shoulder strap slots) and pushes them forward (which helps them get closer to the crotch strap). The inserts can also help your baby's head drop back a little to keep their chin off the chest.

Only use the padding provided by the manufacturer unless they specifically allow the use of rolled clothes or blankets. Some allow for a small, tightly rolled cloth or diaper to be placed between the child and the crotch strap to prevent slouching.

A crotch buckle that is very close to the baby's body and can be adjusted in height can also help with the fit of a convertible seat. If the crotch buckle is too tall, it ends up on the baby's chest (rather than over their belly or diaper area).

Proper Recline

Another issue parents must address when considering an infant car seat is the recline. Car seats must be installed properly to ensure your baby's head doesn't fall forward. All rear-facing car seats have built-in recline indicators. When both are installed at their infant recline position, convertible seats often take up more room compared to infant seats.

It is unsafe to sit an infant too upright as their chin can fall to their chest and make it harder for them to breathe.

Considerations for Premature Babies

Babies born before 37 weeks gestation are considered premature. Premature babies are often much smaller than full-term newborns. Fortunately, many car seat models, including both infant and convertible options, have a minimum weight of just 4 pounds, which may be appropriate for a preemie.

Frequently Asked Questions

How long can you use an infant car seat?

You can use an infant car seat until your baby reaches the maximum height or weight requirements set by the manufacturer (whichever comes first.)

Are convertible car seats safe for infants?

Yes, convertible car seats designed for an infant's specific height and weight are safe to use, provided they are rear-facing and installed properly.

When do babies grow out of an infant car seat?

Most babies will outgrow the infant seat's height maximum before the weight limit and switch to a larger, convertible seat anywhere between 9 months to 2 years of age. The top of the baby's head should always be at least an inch from the top of the seat when buckled in.

What is the weight limit for an infant car seat?

While weight limits vary from seat to seat, most rear-only facing car seats can be used for infants up to 35 pounds. Most convertible seats can be used for babies weighing up to 40–50 pounds.

What comes after an infant car seat?

After your baby "graduates" from an infant car seat, they'll move to a larger, convertible seat or an all-in-one that goes from a rear-facing seat to a forward-facing car seat and later to a booster.

Where should you install an infant car seat?

The middle of the back seat is always the safest place for any child under 13 to ride in a vehicle. But not all cars and trucks have the proper anchors to install a car seat in the middle seat. In that case, place the infant car seat on whichever side it can be installed properly using the lower anchor system or the seatbelt safely and tightly.

What is the safest car seat for a newborn?

The safest car seat for a newborn is one that meets strict federal safety guidelines and is designed for the baby's current size, height, and weight. Because an infant car seat is one of the most important investments parents will make, it makes sense to research various models, check out recent car seat reviews, and ask a pediatrician for guidance.

When do you remove the newborn insert from a car seat?

Some car seats come with a newborn insert to position smaller babies safely and comfortably. If the baby seems wedged into their harness or it is harder to fasten, they may need more space. While most babies no longer need additional padding by the time they reach 6 months of age, parents should always check the manufacturer's instructions before removing newborn inserts.

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