Infant car seats are designed only to be used in the rear-facing position. Convertible car seats. But these are cumbersome. And some of the convertible car seats seem too big for a baby under three months. If the seat is turned forward too early in baby's development, his heavy, wobbly head could lurch forward.
Rear facing is the safest position.
Our choice is the rear-facing infant seat until baby becomes too tall. The usual manufacturer-suggested guideline is twenty pounds. A safer guideline is baby's height. When baby's head protrudes over the top of the seat, it is time for a forward-facing seat. If baby becomes too tall for the car seat, his large head could pitch backward, unprotected during impact.