Seat belts work for everyone, including pregnant women. Like all occupants, they are more likely to be seriously injured if they do not wear seat 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 seat 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 seat belts effective is wearing them properly.
Lap-Shoulder Belt
Seat Belt ExtenderControl Valve Upper Body Spacer Plate Assembly Automatic Transmission Unit
Control Valve Upper Body Spacer Plate Assembly(2)Line(3)Decrease(4)Converter Feed(5)TCC Release(7)Cooler Feed(8)Lube(9)Regulated Apply(10)Compensator Feed(11)Actuator Feed Limit(13)PCS Line(14)PCS R1/456 Clutch(15)Solenoid 1(16)Solenoid 2(17)CSV2 Enable(18)CSV3 Enable(19)R1/456 Clutch Feed(20)R1 Fee ...