Carl Sagan supposedly once said that randomness is clumpy. Those three words have become one of my favorite go-to quotes, particularly when teaching residents and medical students who are often overly impressed with improbable runs of similar diagnoses or exam findings. I love this quote because it is so simple and yet reveals so much about our experience with observing the natural world. Sagan’s ability to offer up insightful nuggets of rational thought, even if he didn’t actually produce this gem, was unmatched and his efforts to bring science and reason to the public have been sorely missed. If you haven’t read any of Sagan’s works, I highly recommend The Demon-Haunted World: Science as a Candle in the Dark.
If you have a coin, and a few hours to kill, record the results of a long run of flips and you’ll see what Sagan meant about the nature of randomness. You will inevitably observe clusters of heads or tails that might seem improbable, but eventually the outcomes will average out to about half of the flips being heads and half resulting in tails. The more trials that you perform, the closer the outcomes will approach 50% for each possible result, assuming you aren’t gaming the system by using a trick coin.
I don’t think that very many people would argue with the fact that on average a coin flip is random chance, although there are still people out there who think that the Earth is flat and that Justin Bieber is a reptilian humanoid. But because of a deeply rooted cognitive bias, the gambler’s fallacy, we frequently fail at recognizing that randomness is clumpy. We accept the established overall odds, but our acceptance wavers in the face of short runs that go against our expectations. This error in logic can lead to the belief, for instance, that after five heads in a row there is a higher than 50% chance that the next flip with land on tails as if to magically even things out.
In my line of work as a pediatric hospitalist, I frequently experience other healthcare professionals making this mistake in a variety of circumstances. There is a known likelihood of bacteremia when an infant less than 28 days of life is evaluated for fever, for example. Despite this, it is common for physicians and nurses to lament, upon seeing fever as the triage chief complaint, that they are due for this life threatening infection after a number of recent febrile neonates have had negative blood cultures. (more…)
A correspondent asked for my opinion of a new book by journalist Jennifer Margulis that is apparently getting a lot of attention in some circles: The Business of Baby: What Doctors Don’t Tell You, What Corporations Try to Sell You, and How to Put Your Pregnancy, Childbirth, and Baby Before Their Bottom Line. I got a copy from the library and read it. It was a painful experience. One of the customer reviews on the Amazon website accurately sums up my own reaction:
There is a great need for an incisive look at all sides of modern maternity care in the United States, because — let’s face it — we all know it’s not perfect. This, however, is not that book.
The author is a strong advocate of home birth, water birth, midwives, “embracing the pain to make you stronger,” “parents know better than doctors,” natural = good, and very early potty training. She thinks bathing a newborn is harmful. She questions the need for well baby checkups: she thinks they are mainly a gimmick to sell vaccines. She questions the (science-based) practice of giving newborns vitamin K and prophylactic eye drops. She is against the use of chemicals in general. She reports that Johnson’s Baby Wash contains “a host of unpronounceable chemicals, some of which are known toxins…and carcinogens.” She doesn’t seem to have grasped the basic principle of toxicology that the poison is in the dose. She is against formula, which she says is killing babies, and against disposable diapers because they contain chemicals and petroleum and because they can cause your child to become infertile. Her only evidence for “infertility” is one study showing that disposable diapers raise scrotal temperatures. Indeed, plastic underpants are probably warm.
When I read that a new study had shown that antihistamines were harmful for patients with morning sickness, I cringed and thought “Here we go again.”
Hyperemesis gravidarum (HG) is a serious complication of pregnancy. Simple morning sickness is more common and less serious. When I started out in medicine, we routinely treated morning sickness with Bendectin. It was a safe and effective remedy, a combination of the antihistamine doxylamine and a B vitamin, pyridoxine. Unfortunately the manufacturer, Merrill Dow Pharmaceuticals, was bombarded with numerous lawsuits claiming that Bendectin caused birth defects. There was a clear scientific consensus that the evidence did not show that Bendectin caused birth defects and there was plentiful evidence of its safety. The lawyers prevailed over the science, and in 1983, Dow voluntarily took Bendectin off the market to avoid further litigation expenses. After the drug’s withdrawal, the rate of birth defects did not decrease, but the rate of hospitalization for hyperemesis gravidarum doubled. (more…)
Many SBM readers will remember the late, great Barry Beyerstein, a luminary of the skeptical movement and author of a classic article that has been cited many times on SBM, an explanation of why bogus therapies seem to work.
One of his greatest personal accomplishments is not as well known: he produced an exceptional daughter, Lindsay Beyerstein, a freelance writer, philosopher, and polymath who stepped into her father’s shoes as a faculty member of the annual Skeptic’s Toolbox workshop after his death and has done a truly admirable job there.
Among Lindsay’s many other activities, she works for the Sidney Hillman Foundation, a nonprofit that honors excellence in socially conscious journalism. One of her goals has been to reward excellence in science journalism. Bob Ortega has just received a Sidney Award for his exposé of a widely used HPV (human papillomavirus) test that is not FDA approved and has an unacceptably high rate of false negative results. Her interview with him was published on the Hillman Foundation website. On SBM, we frequently criticize journalists who get the science wrong. For a change, I’d like to congratulate Mr. Ortega for not only getting the science right, but for accomplishing something that could potentially save lives.
Is this the G-Spot?
The press release proclaims “Study Confirms Anatomic Existence of G-Spot.” The study itself is titled “G-Spot Anatomy: A New Discovery.” It was just published in The Journal of Sexual Medicine. The author, Adam Ostrzenski, is an “internationally renowned gynecologic surgeon” with multiple degrees (MD, PhD, Dr Hab) and many peer-reviewed articles listed in PubMed.
The G-spot, or Gräfenberg Spot, is an area on the anterior wall of the vagina that can be stimulated to produce sexual excitement, stronger orgasms, and maybe even female ejaculation. Its existence is questionable. Wikpedia has an extensive article explaining the controversy and the published evidence, pro and con, with links to the original sources. You can read more than you ever wanted to know about it there, so I won’t bother trying to repeat it here. A 2012 review of the G-spot literature concluded:
Objective measures have failed to provide strong and consistent evidence for the existence of an anatomical site that could be related to the famed G-spot. However, reliable reports and anecdotal testimonials of the existence of a highly sensitive area in the distal anterior vaginal wall raise the question of whether enough investigative modalities have been implemented in the search of the G-spot.
Dr. Ostrzenski claims to have found the G-spot and taken its picture (above). Believers in Bigfoot and the Loch Ness monster have pictures too. They even had “Bigfoot hair” that later turned out to be synthetic wig fibers. Ostrzenski’s “proof” is no more credible than theirs.
An article (and associated news video clip) from ClickOn in Detroit is titled “Alternative treatment helps Michigan doctor beat infertility.” This is a misleading title, and the report is an example of poor science reporting.
Was She Infertile?
The patient in question was a 33-year-old family practice doctor who believed she was infertile. By definition, infertility is failure to conceive after a year of regular intercourse without contraception. She didn’t meet that definition. She only tried for 6 months before seeing a doctor, and then for 2 more months (with some kind of unspecified medicine) and then she consulted a reproductive endocrinologist who apparently told her she was infertile because of a high FSH level. Then she “did her own research” and supposedly found that acupuncture was a key part of infertility treatment. So she sought infertility treatment from an acupuncturist.
From a message posted on Facebook:
Is the pill safe? The International Agency for Research on Cancer in a 2007 study made by 21 scientists reported that the pill causes cancer, giving it the highest level of carcinogenicity, the same as cigarettes and asbestos. It also causes stroke, and significantly increases the risk of heart attacks. Several scientific journals have stated that the natural way of regulating births through the Billings Ovulation Method has no side-effects, and is 99.5 % effective.
The Billings Ovulation Method (BOM) is a method of natural family planning where women are taught to recognize when they have ovulated by examining their cervical mucus, allowing them to avoid intercourse during fertile periods or conversely, to have intercourse during fertile periods when pregnancy is desired. We used to call people who used the rhythm method “parents,” but BOM is more reliable than older abstinence methods.
I’m a big fan of oral contraceptives. They contributed to women’s liberation by giving us a reliable method of planning, delaying, or avoiding pregnancy. They also have medical uses that go beyond contraception. Birth control pills (BCPs) have had such an important impact that they are known as simply “The Pill.” We have always known they were not 100% risk free; but we also know they are less risky than pregnancy itself. There are other methods of birth control; but they are generally less effective and less convenient. For those who want permanent solutions, tubal ligation and vasectomy are available; but even they have occasional failures. What does science tell us about the effectiveness and safety of BCPs as compared to other methods? (more…)
When women live together, do their menstrual cycles tend to synchronize? It’s been a long time since I first heard that claim. I didn’t believe it, for a number of reasons. I had never observed it myself, I saw no plausible mechanism to explain how it could happen, I thought the statistics to prove it would be problematic and complicated, and I suspected that confirmation bias and selective memory might have persuaded people that a spurious correlation existed. How often do women say “Oh, look! We’re having our periods at the same time”? How often do they say “Oh, look! We’re having our periods at different times”? Now that many years have passed since my first encounter, I thought it would be fun to revisit the claim and see whether science has supported it or rejected it.
A perusal of PubMed and other Internet sources left me confused and amused. (more…)
Several questionable sources are spreading alarms about the possible dangers of prenatal ultrasound exams (sonograms). An example is Christine Anderson’s article on the ExpertClick website. In the heading, it says she “Never Liked Ultrasound Technology.”
[She] has never been sold on the safety using Ultrasounds for checking on the fetuses of pregnant women, and for the last decade her fears have been confirmed with a series of studies pointing to possible brain damage to the babies from this technology.
Should We Believe Her?
Should we avoid ultrasounds because Anderson never liked them? Should we trust her judgment that her fears have been confirmed by studies? Who is she?
“Dr.” Christine Anderson is a pediatric chiropractor in Hollywood who believes a lot of things that are not supported by science or reason. Her website mission statement includes
We acknowledge the devastating effects of the vertebral subluxation on human health and therefore recognize that the spines of all children need to be checked soon after birth, so they may grow up healthy.
It also states that “drugs interfere… and weaken the mind, body, and spirit.” Anderson is a homeopath, a craniosacral practitioner, a vegan, and a yoga teacher. She advises her pregnant patients to avoid toxins by only drinking filtered water and only eating organic foods. She sells her own yoga DVD. (more…)
A correspondent asked me to review the book What to Expect When You’re Expecting by Heidi Murkoff and Sharon Mazel. She wrote “I’m very worried about this book.”
She had just seen an NPR article about the book and was alarmed because it provided an excerpt from the book recommending that patients with morning sickness “Try Sea-Bands” and “Go CAM Crazy.” She knew from reading SBM and other science blogs that “going CAM crazy” is not a good idea. She was savvy enough to search Google Books with the title and “CAM” and found more alarming advice. (more…)