Pregnant women should always wear seat belts. Ask your doctor for specific recommendations.
The lap belt should be worn SNUGLY AND AS LOW AS POSSIBLE OVER THE HIPS.
The shoulder belt should be worn across your shoulder properly, but never across the stomach area.
Persons with serious medical conditions also should wear seat belts. Check with your doctor for any special instructions regarding specific medical conditions.

Seat Belt Precautions
Emergency Locking ModeMazda 6 Owners Manual: Height Adjustment
Adjust the head restraint so that the center is even with the top of the passenger's
ears.
To raise a head restraint, pull it up to the desired position.
To lower the head restraint, press the stopcatch release, then push the head
restraint down.
Front outboard seat
Rear outboard seat
...
Mazda 6 Owners Manual: Mazda Radar Cruise Control (MRCC) (Some models)
The Mazda Radar Cruise Control (MRCC) system is designed to maintain headway
control*1 according to the vehicle speed using a radar sensor (front) to detect
the distance to a vehicle ahead, and by presetting the vehicle speed between 30
km/h (19 mph) and 145 km/h (90 mph), the driver is freed ...