Safety belts work for everyone, including pregnant women. Like all occupants, they are more likely to be seriously injured if they do not wear safety belts.

A pregnant woman should wear a lap-shoulder belt, and the lap portion should be worn as low as possible, below the rounding, throughout the pregnancy.
The best way to protect the fetus is to protect the mother. When a safety belt is worn properly, it is more likely that the fetus will not be hurt in a crash. For pregnant women, as for anyone, the key to making safety belts effective is wearing them properly.
Lap-Shoulder Belt
Safety Belt ExtenderSIR System Description and Operation
SIR System Overview
The supplemental inflatable restraint (SIR) system supplements the protection
offered by the occupants Seat Belt System (2). The SIR
system may contain several inflator modules located throughout the vehicle, i.e.
steering wheel module (1), instrument panel module (1),
...
Side Blind Zone Alert (SBZA)
The vehicle may have a Side Blind Zone Alert (SBZA) system. Read this entire
section before using the system.
WARNING
SBZA does not detect vehicles rapidly approaching outside of the side blind
zones, pedestrians, bicyclists, or animals. Failure to use proper care when changing
lanes may res ...
Ultra High Strength Dual Phase Steel
This information provides repair recommendations and general guidelines for
steel classified as Ultra High Strength Dual Phase Steel (Dual
Phase Steel with a tensile strength greater than 800 MPa), also known as DPX.
General Motors recommends the following when repairing or replacing this type ...