The alarming climb of the maternal death rate in the US may be partly due to the way those deaths are counted, according to a study released Thursday.
The new report confirms two trends that have made headlines across the country: that there was a sharp increase in pregnancy-related deaths in Texas, and that black mothers were disproportionately affected.
But the true size of the increase — reported in previous studies as more than doubling in Texas between 2010 and 2012 — won’t be known until there’s a standardized and accurate system for data collection across the whole country, researchers say.
“There is a real increase going on. But there’s also this data problem that really makes it very difficult,” said Marian MacDorman, a research professor at the University of Maryland who led the new study and wrote an accompanying editorial about the accounting issues. “If you don’t know what happened, it’s hard to prevent the deaths. That’s my real concern.”
Fifty years ago, most mothers who died while giving birth had labor complications in the hospital, like hemorrhages and spikes in blood pressure. But today, deaths are more likely to stem from chronic health conditions like obesity and diabetes, sometimes happening weeks or even months after a woman has given birth. It’s only been in the last decade that many states have adopted a system for keeping track of women who die outside of the hospital.
In 2016, MacDorman and her colleagues published a report looking at maternal mortality numbers across the country. Between 2000 and 2014, as maternal deaths across the world steadily plummeted, the US rate increased, the study found, from 18.8 per 100,000 births in 2000 to 23.8 in 2014. (In comparison, the rate in the UK in 2014 was 3.9 per 100,000 births, and in Sweden it was just 2.2.)
That paper’s country-wide stats excluded data from two states whose numbers diverged drastically from the rest of the country: California, which showed a decrease in maternal deaths, and Texas, which saw its rate double between 2010 and 2012. Some pundits speculated that the spike in Texas was linked to Planned Parenthood closures that swept the state in late 2011.
But the doubling of the maternal mortality rate in Texas in two years, MacDorman wrote in the 2016 paper, was difficult to explain “in the absence of war, natural disaster, or severe economic upheaval.”
In the new report, MacDorman tried to dig into those Texas numbers. Either something really alarming was happening in Texas, or there were some serious accounting errors (or both). “Doctors will typically say mothers are older, fatter, and sicker than they used to be. And I just don’t buy that,” MacDorman said.
Her team compared Texas death certificates — which note maternal age, race, and cause of death — from women who died between 2006 and 2010 with those who died between 2011 to 2015. The numbers were so unusual, she said, that there had to be underlying problems in the counting methods.
For example, the reported mortality rates for women over 40 were “implausibly high,” MacDorman said — 36 times higher than the rates for women aged 25 to 29. (In comparison, in the UK, maternal mortality rates for women over 40 are roughly three to four times higher than those aged 25 to 29.) Similarly, the number of Texas women who died of nonspecific causes was unusually high.
The rates probably came out so high, the researchers found, because of simple errors in the way people report a pregnancy-related death: Because women over 40 make up a fairly small part of the total maternal deaths, for example, even a low error rate could have a big impact on the statistics.
Researchers have been worried about these counting methods for years, and some changes are afoot that could lead to improvements. In June of 2017, the Texas legislature passed a law to standardize reporting of pregnancy-related deaths. A maternal mortality task force in the state has also been sifting through death certificates — one at a time — to find out what exactly happened to each woman in Texas who reportedly died of pregnancy-related causes.
The task force is slated to release its report, which analyzes deaths in the peak year of 2012, later this year.
The new study calls attention to “the limitations of the data,” said Lisa Hollier, a medical director at Texas Children’s Hospital, and the chair of the Maternal Mortality and Morbidity Task Force for Texas. “We really need to have that report from the task force that really helps us understand what these numbers really mean.”
Both MacDorman and Hollier stressed that doctors need to drastically rethink how to treat pregnant women and new mothers. “We need to take the focus beyond just the moment of birth,” MacDorman said.
In Texas, health care coverage for childbirth is quite high compared to other states, but drops off severely in the six months after birth. And the closing of hospitals and obstetric services in rural areas, along with racism in medical care, may leave black women at particularly high risk.
“It’s heartbreaking. I practice high risk obstetrics, and I want nothing more than to have every woman have a safe pregnancy and a safe delivery,” Hollier said. “It needs to change.”