How do doctors report maternity-related deaths?
In 2003, California put a new checkbox on death certificates asking if the deceased was pregnant within one year of death. This caught a certain number of deaths that would have slipped through the cracks previously. The codes used on the death certificate also changed slightly in 1999. Most importantly, the World Health Organization, which controls these codes, added definitions for obstetric death.
Why isn’t the rise in deaths simply attributable to better reporting?
Basically, the rise is too big. Doctors are seeing a greater than 300 percent increase between 1996 and 2006. Part of that is certainly attributable to better reporting, but how much? Donna Hoyert at the U.S. Centers for Disease Control and Prevention, Division of Vital Statistics found that the change in reporting codes resulted in about a 13 percent increase.
The checkbox issue is a little more complex, however, because every state asks slightly different questions on the death certificates. What Hoyert found was an across-the-board increase between 2002 and 2003. In states that asked about pregnancy on the death certificate in a single year – 2002 or 2003 – there was a 20 percent increase in maternal mortality. In states that had a question or a checkbox both years, there was a 40 percent increase in maternal mortality.
Note that collection practices hadn’t changed in either example. The difference, 20 percent vs. 40 percent may reflect the fact that states with better collection of data are better able to see changes. So how much is caused by the addition of the checkbox? You can get an idea by comparing states with a checkbox both years (40 percent increase) to states that instituted the checkbox in 2003 (53 percent increase).
Considering this information, Dr. Elliott Main has estimated that 30 percent of the rise can be attributed to better reporting. That leaves 70 percent that could be caused by changes in population and changes in hospitals.
What about the various definitions: pregnancy-related mortality, maternal mortality, and pregnancy-associated mortality?
Pregnancy-associated mortality lumps in all deaths (including women who die in car crashes) of any mother who dies within one year of pregnancy. So, that’s not a very useful measure.
Maternal-mortality refers to all deaths directly relating to pregnancy and birth within 42 days. This misses women like Nancy Lim, who was injured during a cesarean section in 1993, and died from complications of that injury some nine months later. The numbers are slightly lower, but this is the most commonly used measure. California Watch used maternal-mortality numbers to show how the California rate had increased to 16.9 in 2006. This is the most conservative method of counting maternal deaths. Using that rate, California Watch determined that 95 women died in 2006.
A second method – called pregnancy-related mortality – catches some deaths missed by the maternal-mortality rate. Pregnancy-related mortality counts all deaths directly relating to pregnancy and birth within a year of birth (or the end or pregnancy). If you applied that method to California, there were 108 pregnancy-related mortalities in 2006. And the California pregnancy-related death rate was 19.2 per 100,000 that year.
What exactly is the California Maternal Quality Care Collaborative?
It’s a group founded by the California Department of Public Health and the California Perinatal Quality Care Collaborative. It includes state agencies, nonprofits, professional organizations (like the American College of Obstetricians and Gynecologists), universities (it’s based at Stanford), and health care systems (like Kaiser Permanente and Sutter Health). The group is funded through multiple sources, including some state money and support from Stanford University.
The task force formed in 2004 and began conducting the maternal mortality review in 2006.
What exactly is this review that California is conducting and what does it have to do with the report referenced in the story?
It’s called the California Pregnancy Associated Mortality Review, and it’s the first in the state. Researchers carefully went through all the administrative data – the numbers from vital statistics – to see if this rise in deaths was meaningful. They found that, if anything, poor reporting had been hiding the problem and they put together the report referenced in the story. It was meant as a call to action.
Then they began a much larger review. Researchers are checking all the maternal death certificates against baby birth certificates to make sure no women are missed. And then they are examining the medical records of every woman who died after or during a pregnancy. So far, the researchers have completed analysis of the years 2002 and 2003, and information from that data informs the story.
Why haven’t we heard about this before?
For one thing, everybody in obstetrics knows that maternal mortality is a problem in poor countries and that, since the 1930s, it’s been getting better every year in rich countries. So, any evidence to the contrary is hard to swallow.
There’s also the fact that these deaths are so rare that a doctor will probably go his or her entire career without seeing a death: it’s impossible for individuals to see the trend. In fact, you need a population the size of California’s or bigger to get statistically relevant information. Looking at the entire U.S. population would provide even better information, but the national data is messy because every state collects data differently.
Finally, when a mother dies it is often so painful for the family that people don’t talk about it. California Watch was able to find only four relatives of mothers who had died from pregnancy related causes who were willing to talk. California Watch obtained a list of women who had died within one year of pregnancy from the state in 2007, and with this information, we were able to contact about a dozen family members of women who had died from representative causes, but not one of them wanted to share their story.
How much of this problem is caused by cesareans?
There are many, many studies with many different results. On the face of it, cesareans look like they are clearly more dangerous. More women and infants die during or after cesarean delivery than vaginal delivery. But that conclusion is confounded by what’s called sampling error: the sample of women in the C-section group are at a higher risk than the sample of the women in the vaginal-delivery group because some of them are getting cesareans as a last-ditch effort in an emergency, and others are getting cesareans because they have some underlying risk factor.
So what’s the upshot of all this? For a healthy woman, a C-section is pretty safe. The consensus is that it may be slightly more dangerous than vaginal birth. But if you look at the second third and fourth births after that C-section, the risks go up dramatically. That’s because with every new surgery there is more internal scarring, more risk of placenta problems.