The Unique Problems Car Accident Injuries Pose to Pregnant Women

I found the following article over at The New York Times Health Blog both fascinating and alarming.  Here is the article, which everyone, including of course pregnant women, should read:

December 4, 2009, 12:11 am

Protecting Pregnant Women in Car Accidents

Sara Krulwich/The New York Times Pregnant women are particularly vulnerable during car accidents.

Most parents buckle children in car seats to protect them on the road. But how does a pregnant driver protect the child she is carrying?

States are not required to track fetal deaths when reporting accident data, but it is estimated that 300 to 1,000 unborn children die in car accidents each year. The car accident fatality rate for unborn children is about four times the rate for infants and children up to age 4. Car safety experts at Virginia Tech University, funded in part by Ford Motor Company, are trying to develop a computerized crash test model to determine how best to protect pregnant women and their unborn children during a collision. I spoke with Stefan Duma, Virginia Tech’s head of biomechanical engineering, about the research effort and what women can do now to stay safe. Here’s our conversation.

Why are pregnant woman at special risk during a car accident?

The biggest risk with a pregnant occupant is placenta uterine attachment. That’s a delicate attachment, and it doesn’t take a lot of force to detach that. If it gets detached, the baby loses oxygen. That accounts for about 80 percent of the reason a fetus is lost after a car accident. The biggest problem is the steering wheel. The larger the belly, the closer the steering wheel, and the steering wheel hits the abdomen.

Are there special instructions for pregnant women using seat belts?

The three-point belt (a shoulder belt and lap belt) is better for everybody. But with pregnant women, one of the problems is misuse and misinformation. A lot of women don’t like the way belts feel, and they move the shoulder strap or the lap belt will ride up and come up in the middle of the abdomen. Seat belts are designed to load on the bony structures. You want the seat belt on your pelvis. If they are seated right the airbag helps. The seat belt and airbag combination is best.

Are pregnant drivers at higher risk than pregnant passengers?

Most of these cases involve pregnant drivers, but the reason for that is that 80 percent of cars today have a single driver. In the passenger seat, you’re a little better off because you don’t have a steering wheel. But the other interesting statistic is that auto accidents are the single largest cause of death for pregnant women. More pregnant women die in car crashes than in birthing complications. Part of that is due to the fact that for anybody in that age group, say 25 to 35, the number one cause of death is a car accident.

How can you make cars safer for pregnant women?

It’s a complicated process. We’re still trying to understand what level of energy is required to cause damage to pregnant women. How much force, what position, what direction, how much compression of the abdomen will cause placental disruption? You need an extremely detailed computer model. We’re building a model of the human body out of 1 millimeter cubes — a model with 3 million elements. The ability to create that level of detail is very recent.

How do you obtain the data that form the basis of a computer model?

We characterize human tissues. All sorts of medical groups study placental tissue. Within 24 hours of delivery, we cut it into different shapes and push it and pull it to characterize the mechanical response. We do the same with uterine tissue. We also use real world accidents. There are cases where the fetus died and a group of cases where there were no problems. There are different accelerations and velocities. We run those, separating the injury and the no-injury cases, and then we have an idea.

How long will it be before these data are translated into car safety features?

The design cycle for cars is about three years. If I wanted to put a new thing in a car right now the best case is three to four years. What is the perfect belt for a pregnant occupant? It’s a a difficult solution, but it’s something we need to work toward. There are some attachments out there, but none of them are recommended by auto manufacturers. The problem is we don’t really have a good tool to evaluate what they do. The first step is to develop a computer model to evaluate them.

Given that it will be a while before this research is available to consumers, what’s your advice for pregnant women today on how best to protect themselves in a car?

The biggest thing is to wear your seat belt. Keep the lap belt by your legs and stay as far away from the steering wheel as you can. Some vehicles have a button to adjust the height of the brake and gas pedal so shorter people don’t have to sit so close to the steering wheel. And there are after-market pedal extenders. My wife used those. Pedal extenders allowed us to put her in a position further away from the steering wheel. It’s just three inches, but that’s a lot of distance in an accident.

The number of unborn children lost in car accidents is relatively small compared to the estimated 40,000 people who die annually in collisions. Why is there so much effort being focused on this group?

This is actually a bigger issue than the child seat issue, which is something we are very focused on. It’s roughly four times the problem of children dying in car seats. And when you look at the 40,000 crash deaths, a lot of those are the fault of the person — they weren’t wearing a seat belt, or they were drinking and driving. But if you are pregnant and get into a crash, there’s little you can do to protect your fetus.

From a design standpoint, you ask yourself, “What is the population I can help?” If someone is not wearing a seat belt, it’s hard to get them to wear it. If they’re drinking and driving, that’s another issue. But there are things we can do for people who are driving to work, wearing seat belts and getting into crashes. How do we design a better seat belt for that population? This is an area where we can make a difference.