Buying an Infant-Only Car Seat for Your Newborn

dad with newborn car seat
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Parents often assume that they have just one car seat option for newborns: an infant-only car seat carrier that snaps in and out of a base installed in the car.

As a parent, you can choose to use an infant-only car seat for your newborn but you might have other options, such as a convertible car seat. Here's what you need to know before making a selection.

Infant-Only Car Seats

Infant-only car seats face the rear of the vehicle. Some infant car seats have a weight limit of 22 pounds, but most models have a weight limit of 30 pounds or more. Nearly every baby will outgrow their infant-only seat in height long before reaching the 30-pound weight limit.

Preemies and small newborns might go home from the hospital weighing less than 5 pounds. They will need a car seat with a 4-pound minimum rather than a 5-pound minimum (which is found on some infant and many convertible car seats).

Most infant-only car seats also have a stay-in-car base. This feature makes it easy to carry your baby around in the seat when not in your vehicle. Infant-only car seats are sometimes sold as part of a ​travel system that comes with a stroller.

Convertible Car Seats for Newborns

A convertible car seat starts off rear-facing and can be converted to forward-facing. The minimum starting weight for convertibles is not uniform—some seats start at 4 pounds, many at 5 pounds, and others not until closer to 15 pounds.

Some convertible car seats can accommodate a baby from 5 pounds to 40 pounds (or more) when rear-facing. Once they are turned to use forward-facing, the seats can work for a child weighing 40 pounds or more.

Convertible seats can typically be used rear-facing up to 40 to 50 pounds (the exact weight varies by seat).

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.

The size of the car seat does not correlate with how well it will fit a newborn. It is how close the shoulder straps are to your baby's shoulders, the crotch strap to the diaper area, and the ability of the seat to position your baby's head such that their chin stays off their chest.

A car seat's weight limit will be posted on the side label and can also be found in the seat's instruction manual. Make sure you read these documents carefully.

Convertible Seat Inserts and Padding

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.

Another issue parents must address when considering a convertible seat is the recline. You need to make sure that you can achieve the proper infant recline with that car seat in your vehicle and that the seat doesn't interfere with the use of the front seats when it's properly reclined.

When both are installed at their infant recline position, convertible seats often take up more room into the front seat compared to an infant seat.

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

A crotch buckle that has a position 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).

All-in-One Seats

All-in-one car seats, or 3-in-1 car seats, are also an appropriate choice as long as one of the modes is rear-facing. Your newborn should also fit into the height and weight range for rear-facing to ride safely in these car seats.

Remember: the height and weight ranges can be found in the car seat instructions.

Which Car Seat Should You Buy?

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 newborns. The measure of convenience these seats provide is invaluable for some parents.

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.

Check the car seat's labels to ensure your baby fits within the weight 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 transition to a convertible seat.

However, children should continue riding rear-facing for at least another year (but ideally several more years) before turning forward-facing. Rear-facing is the safest way to ride. When shopping for a convertible seat look for one with a rear-facing weight limit of at least 40 pounds.

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  1. AAP. AAP updates recommendations on car seats for children. Updated August 30, 2018.

  2. The Car Seat Lady. How to Position a Newborn Baby’s Head in the Car Seat . Updated February 29, 2016.