Making decisions about your own medical care is tough. Making decisions about a child’s medical care is tougher still. But making decisions about care for your unborn child? Nothing is harder than that. And these days, there is no end to the decisions that must be made: genetic testing? Birth attendant? With or without medication? Hospital, birthing center or home birth?
These are some of the most agonizing decisions most people will ever make. Especially with a first child, most of the terrain is unfamiliar, opportunities for ghastly mistakes seem to be everywhere, and there’s often surprisingly little solid evidence to go on. Most of us listen to our doctors and ask our friends and family members. We maybe do some Internet research and read a few books, or even a study or two. And then, sooner or later, we make a decision and muddle through as best we can.
Carl Michal isn’t like the rest of us. He’s a physicist who spends his time studying the properties of biological materials like silk and hagfish slime. He’s a father. And he doesn’t seem to have much patience for muddling.
When Michal and his wife were expecting their first child six years ago, his wife wanted to give birth at home, not in a hospital. Michal was somewhat alarmed at what, for him, was an unfamiliar idea. So he did what any self-respecting scientist would do: a literature review. He found a study of 862 home births in British Columbia, where he and his family live. It concluded that home births attended by midwives were just as safe for mother and baby as hospital births. The paper eased Michal’s worries, and he and his wife went on to have their first and second children at home with the aid of a midwife.
Then last summer, while Michal’s wife was pregnant with their third child, he happened to hear about a new home birth study on the news. Distressingly, it claimed that babies born at home were two to three times more likely to die in their first month of life than those born in hospitals. Michal was perplexed: how could this new study have arrived at a conclusion that so contradicted his family’s experience–and his own extensive reading of the evidence? What should he and his wife do about the birth of their third child?
That’s the point at which most people throw up their hands in frustration or fall back on the advice of trusted family members or professionals. Being a physicist, Michal turned instead to a closer scrutiny of the numbers. The paper, which had been written by a group of doctors from Maine, was a meta-analysis, combining results from previous studies to calculate composite measurements of 21 outcomes, including newborn deaths. But Michal found that it was impossible to tell which previous studies had been included in or excluded from each composite result. So he wrote a computer program to try to reverse engineer the authors’ process. His program revealed that there was no combination of individual studies that could have given some of the results reported in the paper.
Michal then turned his attention to the statistical program that the Maine doctors had used to perform some of their analyses, which was posted online as part of a free Internet course. Michal realized that the statistical program was flawed; its authors had made errors in translating its formulas from a textbook into their online spreadsheet. Michal found that the errors could have changed some of the conclusions of the paper.
For Michal, these discrepancies were enough to restore his faith in the previous studies and in his own family’s experience. He wasn’t done though. He wanted other families facing the same decision–and the doctors counseling them–to know that the study was flawed. The publishing journal, the American Journal of Obstetrics and Gynecology, declined his demand that they retract the paper, but an internal investigation found mathematical errors in each of the three results from the paper it scrutinized, including the key finding that newborns are more likely to die after home birth. But the correct results didn’t change the paper’s conclusion that home birth is more dangerous for babies than hospital birth, so the journal isn’t retracting the study.
It may seem remarkable that it took a physicist working in his free time to find flaws with a statistical program used in a medical study. But many peer-reviewers consider it beyond the call of duty to check math and ground-truth procedural details.
One errant study does not invalidate the whole body of medical literature, of course. But especially in politicized areas of medicine, such as home birth, such discrepancies only open the door to more uncertainty. We’re told to avoid looking for medical advice on the Internet–a minefield of quacks and misinformation, and contentious blog posts making vitriolic arguments based on scant facts. But when one flaw in the peer-reviewed literature emerges, we’re left not knowing how many others are out there, undetected. We’re left with one more doubt as we try to arrive at some decision we can live with.
As for Michal, he continues to press the journal to retract the Maine study. Already, he estimates the effort has taken a hundred hours over eight months–time that he could have spent on teaching, research, or with own family. For earlier this month, Michal’s third child, a girl, was born, safely, at home.
Image: Wooden birthing forceps used in the 18th Century. Photographed by Dave Russ at the Hunterian Museum and Art Gallery/wikimedia commons.