Most experts recommend installing your car seat during the last few weeks of pregnancy, ideally between weeks 35 and 37. This gives you enough time to get it checked by a professional if needed, while still being early enough to cover the possibility of an early delivery. About 1 in 10 babies in the United States arrives before 37 weeks, so having the seat ready a few weeks before your due date is a practical safeguard rather than an overreaction.
Why 35 to 37 Weeks Is the Sweet Spot
Installing too early isn’t a safety issue, but most parents find that the final weeks of the third trimester strike the right balance. By 35 weeks, you’ve likely chosen your seat and have enough energy to deal with the installation. Waiting until after 37 weeks risks cutting it close if labor starts unexpectedly. If you’re carrying multiples or have been told you’re at higher risk for preterm labor, aim for 32 to 34 weeks instead.
Once the seat is in, you also want a buffer of a week or two to schedule a professional inspection if something feels off. Inspection stations can have limited hours or require appointments, and you don’t want to be scrambling the day before your induction.
What to Install: The Base
Most infant car seat systems come in two pieces: a base that stays buckled into your car and a carrier that clicks in and out. The base is the part you install during pregnancy. It stays in the vehicle semi-permanently, and you’ll snap the carrier onto it each time you drive. This setup lets you buckle your baby into the carrier inside your home, carry them out, and click the whole thing into the base without fumbling with the seatbelt every trip.
Some parents skip the infant carrier system and go straight to a convertible seat that covers newborn through toddler stages. That’s a valid choice, but it means you’ll need to carry your baby to the car and buckle them directly into the seat each time. In cold weather or rain, many parents find the carrier system more practical for the first several months. It’s also worth knowing that some newborns are too small to fit safely in a larger convertible seat right away.
Getting the Installation Right
A properly installed car seat should not move more than one inch in any direction. Grip it near the belt path and try to shift it side to side and front to back. If it moves more than an inch, it needs to be tightened. This is the single most common installation mistake, according to the Children’s Hospital of Philadelphia.
Other frequent errors to check for:
- Shoulder strap position. For rear-facing seats (which all newborns use), the harness straps should thread through slots that sit at or below your baby’s shoulders. The chest clip goes at armpit level.
- Harness snugness. Once your baby is buckled in, try to pinch the strap material at the top of their shoulder. If you can pinch a fold of extra webbing, the harness is too loose.
- Belt path routing. Convertible seats have multiple slots for the seatbelt depending on whether the seat faces forward or backward. Check your manual to confirm you’re using the correct one for rear-facing mode.
- Top tether. If your seat has a top tether strap, attach it to the anchor point in your vehicle and pull it tight. Your car’s manual will show you where the anchor is located.
Practice these checks during pregnancy so you’re comfortable with them before the baby arrives. You won’t want to troubleshoot installation while sleep-deprived with a crying newborn in the backseat.
Getting a Professional Inspection
Certified Child Passenger Safety Technicians can verify your installation for free at inspection stations around the country. You can find a nearby station through NHTSA’s online locator at nhtsa.gov. Many fire stations, police departments, and hospitals host these events, though availability varies by location. Some require appointments, so call ahead.
A technician will check your installation, show you how to adjust the harness for your baby’s size, and walk you through common mistakes. The whole process typically takes 20 to 30 minutes. Scheduling this for around week 36 or 37 gives you time to make corrections before delivery.
What Happens at the Hospital
Hospitals generally expect your baby to leave in a car seat, but policies vary on how closely staff check your setup. NHTSA recommends that hospitals provide education on safe car seat use at discharge, and some facilities have staff or technicians who will walk to the parking lot and verify your installation. Others simply confirm that you have a seat and send you on your way. Final decisions about car seat use rest with the parent, not the hospital.
Don’t count on the hospital to catch installation problems. Treat discharge day as a test of what you’ve already set up, not the time to figure things out. Bring the carrier portion of your seat into your hospital room so you can buckle the baby in before heading to the car. This is much easier than trying to wrangle a newborn into a seat in a cramped backseat.
Check the Expiration Date and Register Your Seat
Car seats expire 6 to 10 years after the manufacture date, depending on the brand. You can find this date on a sticker or label on the bottom or back of the seat. Graco, Chicco, and Baby Trend print expiration dates directly on the seat and base. Britax uses the serial number and manufacture date, which you cross-reference with their website. If you’re using a hand-me-down, check this before installation. An expired seat may have degraded materials that won’t protect your baby in a crash.
Once you’ve confirmed the seat is current, register it with the manufacturer. This ensures you’ll be notified if there’s ever a recall. You can do this by mailing the registration card that came in the box (no postage needed), registering on the manufacturer’s website, or going to safercar.gov/parents and clicking “car seat.” Registration takes a couple of minutes and is easy to forget once the baby arrives, so do it when you unbox the seat.