Each year on average there are more than 750,000 pregnant women in the UK, with the majority regularly using a car throughout their pregnancy. But do conventional seat belts offer pregnant women and their unborn babies the best possible protection? For more than seven years researchers from Loughborough University’s Department of Computer Science have been investigating this issue.
“It was when I was expecting a child myself that I first became aware of the difficulties faced by pregnant women when driving or travelling in cars,” explains Dr Serpil Acar, a specialist in modelling for injury prevention and engineering design for women. “Not only is it uncomfortable to use a standard seatbelt but you also worry about the damage it might do to your unborn baby if you were involved in an accident. I could see that there was a mismatch between pregnant car occupants and current seat belts and I wanted to resolve it.”
Dr Serpil Acar decided to tackle the problem and has spent several years investigating ways to make car travel more comfortable and safer for pregnant women. With her team of researchers she has generated the world’s first ever computer model of a pregnant car occupant, with a detailed representation of a foetus within a uterus. The ‘Expecting’ model was developed to tackle the complexity of pregnant women, by creating the uterus with a foetus and integrating them into an existing MADYMO (MAthematical DYnamic Models computer software) female model. The MADYMO female model was also modified to incorporate the physical size and shape changes that occur during pregnancy and the different seating postures pregnant women adopt.
“Computational human models provide opportunities to simulate accidents without the hazards and they are more economical to use than crash test dummies,” Dr Serpil Acar explains. “A very important feature of successful modelling and simulation is using accurate and realistic data.”
The data for the ‘Expecting’ model was taken from the first ever database of detailed measurements of pregnant women, collected by Dr Acar and her team in an Engineering and Physical Sciences Research Council (EPSRC) funded project, which started in 2001. For this study the team measured more than 100 expectant mothers. The anthropometric details they chose to collect were selected for their applicability to the vehicle design process, and in total they took 49 different measurements of each woman, capturing the many changes women undergo during pregnancy. They also carried out in-depth interviews with them on their experiences of driving and being an occupant in a car whilst pregnant. In addition more than 1000 pregnant women from across the world completed a questionnaire, which was made available on the internet in five different languages.
One of the most striking findings of the project was that car seatbelts were a major concern for pregnant women, with only 11% of those questioned wearing their seatbelts correctly as advised by the Government. National guidelines and medical experts specify that seatbelts should be worn throughout pregnancy, with the diagonal strap placed between the breasts and around the bump while the lap strap is positioned across the hips fitting under the bump.
Further analysis of the data also showed that pregnant women form a significantly different population than male and non-pregnant female populations, not only in the expected abdominal region but also regarding the chest and thigh areas and sitting postures. This information was used to generate guidelines for the automotive industry and pregnant women.
Dr Acar said: “Interviews with the pregnant women highlighted that many expectant mothers experience discomfort so they pull and hold the seatbelt away from their bodies – some partially wear the seatbelt and some do not even wear the seatbelt at all.
After conducting such indepth research into the issues surrounding pregnant car users Dr Acar and her team were able to secure additional funding from the EPSRC to develop a unique safety belt product – SeatBeltPlus – for improved automobile occupant safety. The ultimate goal of the new product is to provide additional safety and improved comfort for the pregnant occupant, without interfering with the safety and comfort of all other car users.
“In the development of SeatBeltPlus we have drawn on the knowledge we have acquired from previous projects and used ‘Expecting’ to create something that provides better protection and enhanced comfort for all. The product is not only for pregnant women but for everyone,” Dr Acar explains. “A prototype of SeatBeltPlus has now been created, comfort tests have been carried out and we are due to start crash test trials in the next few weeks.”
‘Expecting’ is currently being used in two further EPSRC projects. The first is using the computer model in simulations of different crash conditions to investigate the effect of varying crash characteristics on predicting risks to expectant mothers and their foetuses.
“We wanted to be able to see clearly what would happen to a pregnant woman and the unborn child in the event of a car accident. We also needed to examine the crash impacts, both when seat belts are worn correctly according to guidelines and when they are worn incorrectly. We investigated through simulations with ‘Expecting’ whether the pregnant drivers who improvise to increase comfort could be risking their lives and those of their unborn babies in the event of an accident.
“Simulations we conducted with the computational model ‘Expecting’ suggest that wearing the 3-point seat belt according to the guidelines, and the use of airbags, reduced the risks to both mother and baby compared with wearing no seat belt or wearing it partially.”
The next EPSRC project involved working with Thatcham Motor Insurance Repair Research Centre – an independent vehicle safety research centre – using its state-of-the-art crash test facility and an experimental pregnant woman dummy to assess the many commercially available seat belt adaptors. These adaptors alter the position of the lap belt section of the seat belt, pulling it down from the enlarged abdominal area. “This research was not conclusive whether the seat belt adaptors provided additional benefits to the standard 3-point seat belts worn according to the guidelines,” says Dr Acar. “However we felt that if the adaptors encouraged pregnant women to wear seat belts more correctly when driving or travelling in a car, then this is a good thing.”
The second project, funded by the EPSRC through the University’s Innovative Manufacturing and Construction Research Centre (IMCRC), is focussing on different categories of cars and assessing which offer the best protection for pregnant women. “This project is really about finding out what aspects of different cars make a positive impact on the safety of pregnant women,” said Dr Acar. “By gaining a better understanding of this we can determine which features of the car make a real difference and should, if possible, be adopted into all makes and models.”
The work carried out by Dr Acar and her team is the world’s most comprehensive body of research in the area of pregnant women and motor vehicles. It has, and continues to have, a major impact on the safety of pregnant car users, providing much needed guidance to the motor industry. The team is internationally recognised for its work in this field and has ensured that the needs of pregnant car users and their unborn babies are not ignored.
Dr Acar would like to hear from women who want to discuss any design related difficulties they have experienced during pregnancy.
