Car seats certified for use up to 13 Kg (R44/04) or up to 75 or 87 cm tall (R129) are the best travel system for newborn babies. They are small and come equipped with inserts that help to adapt baby's small body to the car seat. It is very important to ensure that the harness (inner belt) can be adjusted to different heights as the baby grows. It must be shoulder height and easy to tighten. Adjust the harness every day ensuring that the space between the harness and the shoulder is only enough to slip a finger under.