What happens to pregnant women in a crash?

Nowadays, every passenger in a car is protected by comprehensive safety systems. Only one is not - the unborn child. To get information about what an expectant mother and her unborn baby are exposed to in the event of an accident, Volvo Cars has developed the first official computer model of a "pregnant" dummy.
"Now we can cover the whole life cycle," says Camilla Palmertz, biomechanist at Volvo Cars' safety centre. "A big advantage of this model is that we can scale the mother and baby to exactly the size we want to study." The virtual dummy is a heavily pregnant woman - because that is the stage when the unborn child is most at risk in an accident. With the tests that are now being carried out, Volvo wants to determine what influence the seat belt and airbag have on the expectant mother and her unborn baby in simulated accidents. The computer model makes it possible to study in great detail the movements of the seatbelt and the influences of the seatbelt and airbag on the uterus, placenta and foetus. It is also possible to observe how the foetus moves in relation to the mother's body.

First "pregnant" dummy in the world	Camilla Palmertz

But the model can do much more. It could also be used to test new forms of seat belts and other safety systems. "I am sure that the three-point belt can be further developed to provide even more comfort and protection," says Camilla Palmertz. Today, many pregnant women wonder if the seat belt will harm their unborn baby in an accident. The researchers all agree that it is advisable to wear the seat belt at all times.

"But it is important that it is put on correctly. It should run between the breasts and rest as low as possible on the hips. The lap belt should not slide up onto the woman's stomach," Camilla Palmertz explains. "That could harm the baby." In an accident, the pregnant woman's chest and pelvis will be held back by the belt, but her abdomen will move in the direction dictated by the forces created in the accident. Because the fetus floats freely in her abdomen, there are two main types of injury. The more common is a partial or complete placental abruption, which means that the baby is no longer getting enough oxygen. In rarer cases, the baby's head is injured when it bumps against one of the bones in the mother's pelvis. "We believe that the placenta detaches because, unlike the relatively elastic, deformable uterus, it is not as flexible when accelerated," Camilla Palmertz explains.

Over the years, researchers and vehicle manufacturers have compiled a lot of evidence on how best to protect adults and children from the effects of a car crash. But there has been little research on unborn babies in car accidents. In a study by the Swedish University of Halmstad, the women surveyed said they always wore their seat belts before pregnancy. During pregnancy, 7 percent refrained from doing so. The reasons: The belt chafes, it is difficult to put on the belt and the expectant mothers were afraid of hurting the baby. Almost half of the women had the problem of the belt riding up their belly instead of sitting on their hips. In a similar study in the USA, even the majority of women had stated that wearing the seat belt was uncomfortable, that it chafed and that it slid up the stomach. Here, the proportion of women who do not use the belt because of the comfort restrictions was as high as 13 percent.

"That is why this pregnant dummy is so important," says Camilla Palmertz. "We need to have more information to be able to develop the optimal protection for the expectant mother and the unborn child. One thing we know for sure now is that pregnant women should always wear a seatbelt and make sure the lap belt goes under the belly."