Pregnancy Seat Belt Adjusters

 Pregnancy seat belt adjusters, more accurately called seat belt positioners, are devices that redirect the lap belt so that the belt is no longer resting against the user's belly. This new routing is intended to reduce the pressure of the seat belt on the abdomen in a crash. 

At first glance this sounds like a good idea. The lap belt can potentially press against a fetus in a crash. Reducing that pressure would presumably make the fetus safer. However, the main cause of injury for unborn babies in crashes is placental abruption, a medical condition where the placenta detaches from the wall of the uterus. Placental abruption can result from a number of different factors, many of which are not related to the lap belt. Removing the variable of the lap belt does not eliminate the risk of abruption and may increase risk in other ways.

When using a pregnancy seat belt positioner, the user is modifying a safety system with a device that is not approved by the vehicle manufacturer. The seat belt is no longer being used the way that it is designed, tested, and proven to save lives.

There is a great deal of evidence that wearing the seat belt properly increases safety for pregnant vehicle occupants in crashes. There is no evidence that seat belt positioners increase safety. In fact, crash tests have shown that a pregnancy seat belt positioner will decrease a user’s safety.  

Many seat belt positioner manufacturers claim that their product is crash tested without providing any further information. We have no way of knowing what the tests involved, how the positioner performed, or if it was even tested at all. Products like car seats say “meets or exceeds FMVSS 213 standards.” This means that the car seat was tested to and passed a certain standard. We do not have any of those assurances with a pregnancy seat belt positioner. 

ADAC in Germany independently crash tested common types of pregnancy seat belt positioners using accepted crash test methods. All of them caused the crash test dummy to move forward further before coming to a stop than a properly used seat belt. Moving further forward before stopping increases internal forces on a fetus and can lead to more significant injuries for the fetus and the pregnant occupant. 

Plastic hook positioners tested by ADAC broke during crash tests. The hook completely breaking leaves dangerous slack in the seat belt and will increase injuries. Nothing was holding the lap belt against the dummy once the plastic hook failed.

Metal hook positioners also failed the test. They came up and hit the dummy in the groin, which can cause its own injuries, in addition to the dummy moving further forward. 

Webbing positioners that buckle around the lap belt did not mechanically fail like the hooks did. However, they created slack in the lap belt and again caused the dummy to move further forward. A pregnant person using a webbing positioner is still at a greater risk of injury than someone using the seat belt as recommended.

 Some seat belt positioner advertisements claim that their products are "legal" or "certified." Stating they are legal implies they are somehow approved. Seat belt positioners are only legal in the sense that there is no law against their use. There are also no U.S. or international standards to certify a pregnancy seat belt positioner. Any claims that a seat belt positioner is approved or certified are not true.

 Seat belts are required to meet rigorous standards for design, construction, and crash performance. Drivers and passengers know they can trust that the seat belt is safe to use. Pregnancy seat belt positioners do not carry any of those guarantees. Manufacturers are free to build seat belt positioners with any design and any materials they choose. 

The most common style of positioner consists of a plastic hook attached to a webbing strap that wraps underneath the vehicle seat.  The plastic hook style positioners often claim to have a steel core with a plastic outer shell. An investigation cut open three common brands of plastic hooks that claimed to have a steel core and did not find a steel core in any models.

Most styles of seat belt positioners use a strap that wraps underneath the vehicle seat. This strap is routed around compressible, non-load bearing parts of the vehicle seat, rather than being anchored to hard points in the car like a seat belt.