Pregnant crash test dummies

Volvo Car Corporation has developed the world's first official computer model of a pregnant crash dummy. The 'virtual' dummy demonstrates a late stage of her pregnancy when an unborn baby is at greatest risk in an accident. The basic geometry was completed in January 2002 and much time has since been devoted to refining the model. "Now it's finished and we've started running simulated front-end impact tests on it," says Camilla Palmertz, a biomechanical engineer at the Volvo Cars Safety Centre. "One big advantage is that both mother and baby can be scaled up or down to the size we want to study." The purpose of these initial tests is to study how the virtual mother-to-be and her unborn baby are affected by the seat belt and airbag in simulated collisions. The computer model makes it possible to study how the belt moves, the influence of belt and airbag on the uterus, placenta and foetus and how the foetus moves in relation to the mother's body. The model can also be used to test new designs for seat belts and other safety systems. Many pregnant women wonder whether the seat belt could harm their unborn baby if they are involved in a car accident. Researchers all agree, however, that they should always wear their seat belt. "But it's important to wear it in the right way. The lap section of the belt mustn't be allowed to ride up in front of the woman's tummy," says Palmertz. "That could harm the baby." In a crash, the pregnant woman's thorax and pelvis are both restrained by the belt, but her abdomen is free to move in the direction determined by the particular forces arising from the impact. Because the foetus is floating free inside her, injuries tend to fall into two main types. The more common of the two occurs when the placenta becomes either partially or completely detached, which means that the baby cannot get enough oxygen. Another, less likely scenario is for the head of the baby to be injured if it hits one of the bones of the mother's pelvis. Even though there is still a great deal to learn, Palmertz is philosophical about the project. "Now we've covered the whole life-cycle," she says.